Bot-S: The Complete Works of Aristotle

THE ATHENIAN CONSTITUTION

by Aristotle

...[They were tried] by a court empanelled from among the noble families, and sworn upon the sacrifices. The
part of accuser was taken by Myron. They were found guilty of the sacrilege, and their bodies were cast out
of their graves and their race banished for evermore. In view of this expiation, Epimenides the Cretan
performed a purification of the city.

After this event there was contention for a long time between the upper classes and the populace. Not only
was the constitution at this time oligarchical in every respect, but the poorer classes, men, women, and
children, were the serfs of the rich. They were known as Pelatae and also as Hectemori, because they
cultivated the lands of the rich at the rent thus indicated. The whole country was in the hands of a few
persons, and if the tenants failed to pay their rent they were liable to be haled into slavery, and their children
with them. All loans secured upon the debtor's person, a custom which prevailed until the time of Solon, who
was the first to appear as the champion of the people. But the hardest and bitterest part of the constitution in
the eyes of the masses was their state of serfdom. Not but what they were also discontented with every other

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feature of their lot; for, to speak generally, they had no part nor share in anything.

Now the ancient constitution, as it existed before the time of Draco, was organized as follows. The
magistrates were elected according to qualifications of birth and wealth. At first they governed for life, but
subsequently for terms of ten years. The first magistrates, both in date and in importance, were the King, the
Polemarch, and the Archon. The earliest of these offices was that of the King, which existed from ancestral
antiquity. To this was added, secondly, the office of Polemarch, on account of some of the kings proving
feeble in war; for it was on this account that Ion was invited to accept the post on an occasion of pressing
need. The last of the three offices was that of the Archon, which most authorities state to have come into
existence in the time of Medon. Others assign it to the time of Acastus, and adduce as proof the fact that the
nine Archons swear to execute their oaths 'as in the days of Acastus,' which seems to suggest that it was in his
time that the descendants of Codrus retired from the kingship in return for the prerogatives conferred upon
the Archon. Whichever way it may be, the difference in date is small; but that it was the last of these
magistracies to be created is shown by the fact that the Archon has no part in the ancestral sacrifices, as the
King and the Polemarch have, but exclusively in those of later origin. So it is only at a comparatively late
date that the office of Archon has become of great importance, through the dignity conferred by these later
additions. The Thesmothetae were many years afterwards, when these offices had already become annual,
with the object that they might publicly record all legal decisions, and act as guardians of them with a view to
determining the issues between litigants. Accordingly their office, alone of those which have been mentioned,
was never of more than annual duration.

Such, then, is the relative chronological precedence of these offices. At that time the nine Archons did not all
live together. The King occupied the building now known as the Boculium, near the Prytaneum, as may be
seen from the fact that even to the present day the marriage of the King's wife to Dionysus takes place there.
The Archon lived in the Prytaneum, the Polemarch in the Epilyceum. The latter building was formerly called
the Polemarcheum, but after Epilycus, during his term of office as Polemarch, had rebuilt it and fitted it up, it
was called the Epilyceum. The Thesmothetae occupied the Thesmotheteum. In the time of Solon, however,
they all came together into the Thesmotheteum. They had power to decide cases finally on their own
authority, not, as now, merely to hold a preliminary hearing. Such then was the arrangement of the
magistracies. The Council of Areopagus had as its constitutionally assigned duty the protection of the laws;
but in point of fact it administered the greater and most important part of the government of the state, and
inflicted personal punishments and fines summarily upon all who misbehaved themselves. This was the
natural consequence of the facts that the Archons were elected under qualifications of birth and wealth, and
that the Areopagus was composed of those who had served as Archons; for which latter reason the
membership of the Areopagus is the only office which has continued to be a life-magistracy to the present
day.

Such was, in outline, the first constitution, but not very long after the events above recorded, in the
archonship of Aristaichmus, Draco enacted his ordinances. Now his constitution had the following form. The
franchise was given to all who could furnish themselves with a military equipment. The nine Archons and the
Treasurers were elected by this body from persons possessing an unencumbered property of not less than ten
minas, the less important officials from those who could furnish themselves with a military equipment, and
the generals [Strategi] and commanders of the cavalry [Hipparchi] from those who could show an
unencumbered property of not less than a hundred minas, and had children born in lawful wedlock over ten
years of age. These officers were required to hold to bail the Prytanes, the Strategi, and the Hipparchi of the
preceding year until their accounts had been audited, taking four securities of the same class as that to which

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the Strategi and the Hipparchi belonged. There was also to be a Council, consisting of four hundred and one
members, elected by lot from among those who possessed the franchise. Both for this and for the other
magistracies the lot was cast among those who were over thirty years of age; and no one might hold office
twice until every one else had had his turn, after which they were to cast the lot afresh. If any member of the
Council failed to attend when there was a sitting of the Council or of the Assembly, he paid a fine, to the
amount of three drachmas if he was a Pentacosiomedimnus, two if he was a Knight, and One if he was a
Zeugites. The Council of Areopagus was guardian of the laws, and kept watch over the magistrates to see that
they executed their offices in accordance with the laws. Any person who felt himself wronged might lay an
information before the Council of Areopagus, on declaring what law was broken by the wrong done to him.
But, as has been said before, loans were secured upon the persons of the debtors, and the land was in the
hands of a few.

Since such, then, was the organization of the constitution, and the many were in slavery to the few, the people
rose against the upper class. The strife was keen, and for a long time the two parties were ranged in hostile
camps against one another, till at last, by common consent, they appointed Solon to be mediator and Archon,
and committed the whole constitution to his hands. The immediate occasion of his appointment was his
poem, which begins with the words:

I behold, and within my heart deep sadness has claimed its place,
As I mark the oldest home of the ancient Ionian race
Slain by the sword.

In this poem he fights and disputes on behalf of each party in turn against the other, and finally he advises
them to come to terms and put an end to the quarrel existing between them. By birth and reputation Solon
was one of the foremost men of the day, but in wealth and position he was of the middle class, as is generally
agreed, and is, indeed, established by his own evidence in these poems, where he exhorts the wealthy not to
be grasping.

But ye who have store of good, who are sated and overflow,

Restrain your swelling soul, and still it and keep it low:

Let the heart that is great within you he trained a lowlier way;

Ye shall not have all at your will, and we will not for ever obey. Indeed, he constantly fastens the blame of
the conflict on the rich; and accordingly at the beginning of the poem he says that he fears' the love of wealth
and an overweening mind', evidently meaning that it was through these that the quarrel arose.

As soon as he was at the head of affairs, Solon liberated the people once and for all, by prohibiting all loans
on the security of the debtor's person: and in addition he made laws by which he cancelled all debts, public
and private. This measure is commonly called the Seisachtheia [= removal of burdens], since thereby the
people had their loads removed from them. In connexion with it some persons try to traduce the character of
Solon. It so happened that, when he was about to enact the Seisachtheia, he communicated his intention to
some members of the upper class, whereupon, as the partisans of the popular party say, his friends stole a
march on him; while those who wish to attack his character maintain that he too had a share in the fraud
himself. For these persons borrowed money and bought up a large amount of land, and so when, a short time
afterwards, all debts were cancelled, they became wealthy; and this, they say, was the origin of the families

THE ATHENIAN CONSTITUTION

which were afterwards looked on as having been wealthy from primeval times. However, the story of the
popular party is by far the most probable. A man who was so moderate and public-spirited in all his other
actions, that when it was within his power to put his fellow-citizens beneath his feet and establish himself as
tyrant, he preferred instead to incur the hostility of both parties by placing his honour and the general welfare
above his personal aggrandisement, is not likely to have consented to defile his hands by such a petty and
palpable fraud. That he had this absolute power is, in the first place, indicated by the desperate condition the
country; moreover, he mentions it himself repeatedly in his poems, and it is universally admitted. We are
therefore bound to consider this accusation to be false.

Next Solon drew up a constitution and enacted new laws; and the ordinances of Draco ceased to be used, with
the exception of those relating to murder. The laws were inscribed on the wooden stands, and set up in the
King's Porch, and all swore to obey them; and the nine Archons made oath upon the stone, declaring that they
would dedicate a golden statue if they should transgress any of them. This is the origin of the oath to that
effect which they take to the present day. Solon ratified his laws for a hundred years; and the following was
the fashion in which he organized the constitution. He divided the population according to property into four
classes, just as it had been divided before, namely, Pentacosiomedimni, Knights, Zeugitae, and Thetes. The
various magistracies, namely, the nine Archons, the Treasurers, the Commissioners for Public Contracts
(Poletae), the Eleven, and Clerks (Colacretae), he assigned to the Pentacosiomedimni, the Knights, and the
Zeugitae, giving offices to each class in proportion to the value of their rateable property. To who ranked
among the Thetes he gave nothing but a place in the Assembly and in the juries. A man had to rank as a
Pentacosiomedimnus if he made, from his own land, five hundred measures, whether liquid or solid. Those
ranked as Knights who made three hundred measures, or, as some say, those who were able to maintain a
horse. In support of the latter definition they adduce the name of the class, which may be supposed to be
derived from this fact, and also some votive offerings of early times; for in the Acropolis there is a votive
offering, a statue of Diphilus, bearing this inscription:

The son of Diphilus, Athenion night,
Raised from the Thetes and become a knight,
Did to the gods this sculptured charger bring,
For his promotion a thank-offering.

And a horse stands in evidence beside the man, implying that this was what was meant by belonging to the
rank of Knight. At the same time it seems reasonable to suppose that this class, like the Pentacosiomedimni,
was defined by the possession of an income of a certain number of measures. Those ranked as Zeugitae who
made two hundred measures, liquid or solid; and the rest ranked as Thetes, and were not eligible for any
office. Hence it is that even at the present day, when a candidate for any office is asked to what class he
belongs, no one would think of saying that he belonged to the Thetes.

The elections to the various offices Solon enacted should be by lot, out of candidates selected by each of the
tribes. Each tribe selected ten candidates for the nine archonships, and among these the lot was cast. Hence it
is still the custom for each tribe to choose ten candidates by lot, and then the lot is again cast among these. A
proof that Solon regulated the elections to office according to the property classes may be found in the law
still in force with regard to the Treasurers, which enacts that they shall be chosen from the
Pentacosiomedimni. Such was Solon's legislation with respect to the nine Archons; whereas in early times the
Council of Areopagus summoned suitable persons according to its own judgement and appointed them for
the year to the several offices. There were four tribes, as before, and four tribe-kings. Each tribe was divided
into three Trittyes [=Thirds], with twelve Naucraries in each; and the Naucraries had officers of their own,

THE ATHENIAN CONSTITUTION

called Naucrari, whose duty it was to superintend the current receipts and expenditure. Hence, among the
laws of Solon now obsolete, it is repeatedly written that the Naucrari are to receive and to spend out of the
Naucraric fund. Solon also appointed a Council of four hundred, a hundred from each tribe; but he assigned
to the Council of the Areopagus the duty of superintending the laws, acting as before as the guardian of the
constitution in general. It kept watch over the affairs of the state in most of the more important matters, and
corrected offenders, with full powers to inflict either fines or personal punishment. The money received in
fines it brought up into the Acropolis, without assigning the reason for the mulct. It also tried those who
conspired for the overthrow of the state, Solon having enacted a process of impeachment to deal with such
offenders. Further, since he saw the state often engaged in internal disputes, while many of the citizens from
sheer indifference accepted whatever might turn up, he made a law with express reference to such persons,
enacting that any one who, in a time civil factions, did not take up arms with either party, should lose his
rights as a citizen and cease to have any part in the state.

Such, then, was his legislation concerning the magistracies. There are three points in the constitution of Solon
which appear to be its most democratic features: first and most important, the prohibition of loans on the
security of the debtor's person; secondly, the right of every person who so willed to claim redress on behalf of
any one to whom wrong was being done; thirdly, the institution of the appeal to the jurycourts; and it is to
this last, they say, that the masses have owed their strength most of all, since, when the democracy is master
of the voting-power, it is master of the constitution. Moreover, since the laws were not drawn up in simple
and explicit terms (but like the one concerning inheritances and wards of state), disputes inevitably occurred,
and the courts had to decide in every matter, whether public or private. Some persons in fact believe that
Solon deliberately made the laws indefinite, in order that the final decision might be in the hands of the
people. This, however, is not probable, and the reason no doubt was that it is impossible to attain ideal
perfection when framing a law in general terms; for we must judge of his intentions, not from the actual
results in the present day, but from the general tenor of the rest of his legislation.

These seem to be the democratic features of his laws; but in addition, before the period of his legislation, he
carried through his abolition of debts, and after it his increase in the standards of weights and measures, and
of the currency. During his administration the measures were made larger than those of Pheidon, and the
mina, which previously had a standard of seventy drachmas, was raised to the full hundred. The standard coin
in earlier times was the two-drachma piece. He also made weights corresponding with the coinage,
sixty-three minas going to the talent; and the odd three minas were distributed among the staters and the
other values.

When he had completed his organization of the constitution in the manner that has been described, he found
himself beset by people coming to him and harassing him concerning his laws, criticizing here and
questioning there, till, as he wished neither to alter what he had decided on nor yet to be an object of ill will
to every one by remaining in Athens, he set off on a journey to Egypt, with the combined objects of trade and
travel, giving out that he should not return for ten years. He considered that there was no call for him to
expound the laws personally, but that every one should obey them just as they were written. Moreover, his
position at this time was unpleasant. Many members of the upper class had been estranged from him on
account of his abolition of debts, and both parties were alienated through their disappointment at the
condition of things which he had created. The mass of the people had expected him to make a complete
redistribution of all property, and the upper class hoped he would restore everything to its former position, or,

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at any rate, make but a small change. Solon, however, had resisted both classes. He might have made himself
a despot by attaching himself to whichever party he chose, but he preferred, though at the cost of incurring
the enmity of both, to be the saviour of his country and the ideal lawgiver.

The truth of this view of Solon's policy is established alike by common consent, and by the mention he has
himself made of the matter in his poems. Thus:

I gave to the mass of the people such rank as befitted their need,

I took not away their honour, and I granted naught to their greed;

While those who were rich in power, who in wealth were glorious and

great,

I bethought me that naught should befall them unworthy their

splendour and state;

So I stood with my shield outstretched, and both were sale in its

sight,

And I would not that either should triumph, when the triumph was

not with right.

Again he declares how the mass of the people ought to be treated:

But thus will the people best the voice of their leaders obey,
When neither too slack is the rein, nor violence holdeth the sway;
For indulgence breedeth a child, the presumption that spurns control,

When riches too great are poured upon men of unbalanced soul.

And again elsewhere he speaks about the persons who wished to redistribute the land:

So they came in search of plunder, and their cravings knew no hound,
Every one among them deeming endless wealth would here be found.
And that I with glozing smoothness hid a cruel mind within.
Fondly then and vainly dreamt they; now they raise an angry din,
And they glare askance in anger, and the light within their eyes
Burns with hostile flames upon me. Yet therein no justice lies.
All I promised, fully wrought I with the gods at hand to cheer,
Naught beyond in folly ventured. Never to my soul was dear
With a tyrant's force to govern, nor to see the good and base
Side by side in equal portion share the rich home of our race.

Once more he speaks of the abolition of debts and of those who before were in servitude, but were released
owing to the Seisachtheia:

Of all the aims for which I summoned forth
The people, was there one I compassed not?
Thou, when slow time brings justice in its train,

mighty mother of the Olympian gods,

Dark Earth, thou best canst witness, from whose breast

1 swept the pillars broadcast planted there,

And made thee free, who hadst been slave of yore.
And many a man whom fraud or law had sold
For from his god-built land, an outcast slave,
I brought again to Athens; yea, and some,
Exiles from home through debt's oppressive load,
Speaking no more the dear ATHENIAN tongue,
But wandering far and wide, I brought again;

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And those that here in vilest slavery

Crouched 'neath a master's frown, I set them free.

Thus might and right were yoked in harmony,

Since by the force of law I won my ends

And kept my promise. Equal laws I gave

To evil and to good, with even hand

Drawing straight justice for the lot of each.

But had another held the goad as

One in whose heart was guile and greediness,

He had not kept the people back from strife.

For had I granted, now what pleased the one,

Then what their foes devised in counterpoise,

Of many a man this state had been bereft.

Therefore I showed my might on every side,

Turning at bay like wolf among the hounds.

And again he reviles both parties for their grumblings in the times that followed:

Nay, if one must lay blame where blame is due,

Wer't not for me, the people ne'er had set

Their eyes upon these blessings e'en in dreams:-

While greater men, the men of wealthier life,

Should praise me and should court me as their friend.

For had any other man, he says, received this exalted post,

He had not kept the people hack, nor ceased
Til he had robbed the richness of the milk.
But I stood forth a landmark in the midst,
And barred the foes from battle.

Such then, were Solon's reasons for his departure from the country. After his retirement the city was still torn
by divisions. For four years, indeed, they lived in peace; but in the fifth year after Solon's government they
were unable to elect an Archon on account of their dissensions, and again four years later they elected no
Archon for the same reason. Subsequently, after a similar period had elapsed, Damasias was elected Archon;
and he governed for two years and two months, until he was forcibly expelled from his office. After this, it
was agreed, as a compromise, to elect ten Archons, five from the Eupatridae, three from the Agroeci, and two
from the Demiurgi, and they ruled for the year following Damasias. It is clear from this that the Archon was
at the time the magistrate who possessed the greatest power, since it is always in connexion with this office
that conflicts are seen to arise. But altogether they were in a continual state of internal disorder. Some found
the cause and justification of their discontent in the abolition of debts, because thereby they had been reduced
to poverty; others were dissatisfied with the political constitution, because it had undergone a revolutionary
change; while with others the motive was found in personal rivalries among themselves. The parties at this
time were three in number. First there was the party of the Shore, led by Megacles the son of Alcmeon, which
was considered to aim at a moderate form of government; then there were the men of the Plain, who desired
an oligarchy and were led by Lycurgus; and thirdly there were the men of the Highlands, at the head of whom
was Pisistratus, who was looked on as an extreme democrat. This latter party was reinforced by those who
had been deprived of the debts due to them, from motives of poverty, and by those who were not of pure
descent, from motives of personal apprehension. A proof of this is seen in the fact that after the tyranny was
overthrown a revision was made of the citizen-roll, on the ground that many persons were partaking in the
franchise without having a right to it. The names given to the respective parties were derived from the
districts in which they held their lands.

THE ATHENIAN CONSTITUTION
14

Pisistratus had the reputation of being an extreme democrat, and he also had distinguished himself greatly in
the war with Megara. Taking advantage of this, he wounded himself, and by representing that his injuries had
been inflicted on him by his political rivals, he persuaded the people, through a motion proposed by Aristion,
to grant him a bodyguard. After he had got these 'club-bearers', as they were called, he made an attack with
them on the people and seized the Acropolis. This happened in the archonship of Corneas, thirty-one years
after the legislation of Solon. It is related that, when Pisistratus asked for his bodyguard, Solon opposed the
request, and declared that in so doing he proved himself wiser than half the people and braver than the
rest,-wiser than those who did not see that Pisistratus designed to make himself tyrant, and braver than those
who saw it and kept silence. But when all his words availed nothing he carried forth his armour and set it up
in front of his house, saying that he had helped his country so far as lay in his power (he was already a very
old man), and that he called on all others to do the same. Solon's exhortations, however, proved fruitless, and
Pisistratus assumed the sovereignty. His administration was more like a constitutional government than the
rule of a tyrant; but before his power was firmly established, the adherents of Megacles and Lycurgus made a
coalition and drove him out. This took place in the archonship of Hegesias, five years after the first
establishment of his rule. Eleven years later Megacles, being in difficulties in a party struggle, again
opened-negotiations with Pisistratus, proposing that the latter should marry his daughter; and on these terms
he brought him back to Athens, by a very primitive and simple-minded device. He first spread abroad a
rumour that Athena was bringing back Pisistratus, and then, having found a woman of great stature and
beauty, named Phye (according to Herodotus, of the deme of Paeania, but as others say a Thracian
flower-seller of the deme of Collytus), he dressed her in a garb resembling that of the goddess and brought
her into the city with Pisistratus. The latter drove in on a chariot with the woman beside him, and the
inhabitants of the city, struck with awe, received him with adoration.

In this manner did his first return take place. He did not, however, hold his power long, for about six years
after his return he was again expelled. He refused to treat the daughter of Megacles as his wife, and being
afraid, in consequence, of a combination of the two opposing parties, he retired from the country. First he led
a colony to a place called Rhaicelus, in the region of the Thermaic gulf; and thence he passed to the country
in the neighbourhood of Mt. Pangaeus. Here he acquired wealth and hired mercenaries; and not till ten years
had elapsed did he return to Eretria and make an attempt to recover the government by force. In this he had
the assistance of many allies, notably the Thebans and Lygdamis of Naxos, and also the Knights who held the
supreme power in the constitution of Eretria. After his victory in the battle at Pallene he captured Athens, and
when he had disarmed the people he at last had his tyranny securely established, and was able to take Naxos
and set up Lygdamis as ruler there. He effected the disarmament of the people in the following manner. He
ordered a parade in full armour in the Theseum, and began to make a speech to the people. He spoke for a
short time, until the people called out that they could not hear him, whereupon he bade them come up to the
entrance of the Acropolis, in order that his voice might be better heard. Then, while he continued to speak to
them at great length, men whom he had appointed for the purpose collected the arms and locked them up in
the chambers of the Theseum hard by, and came and made a signal to him that it was done. Pisistratus
accordingly, when he had finished the rest of what he had to say, told the people also what had happened to
their arms; adding that they were not to be surprised or alarmed, but go home and attend to their private
affairs, while he would himself for the future manage all the business of the state.

Such was the origin and such the vicissitudes of the tyranny of Pisistratus. His administration was temperate,
as has been said before, and more like constitutional government than a tyranny. Not only was he in every

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respect humane and mild and ready to forgive those who offended, but, in addition, he advanced money to the
poorer people to help them in their labours, so that they might make their living by agriculture. In this he had
two objects, first that they might not spend their time in the city but might be scattered over all the face of the
country, and secondly that, being moderately well off and occupied with their own business, they might have
neither the wish nor the time to attend to public affairs. At the same time his revenues were increased by the
thorough cultivation of the country, since he imposed a tax of one tenth on all the produce. For the same
reasons he instituted the local justices,' and often made expeditions in person into the country to inspect it and
to settle disputes between individuals, that they might not come into the city and neglect their farms. It was in
one of these progresses that, as the story goes, Pisistratus had his adventure with the man of Hymettus, who
was cultivating the spot afterwards known as 'Tax-free Farm'. He saw a man digging and working at a very
stony piece of ground, and being surprised he sent his attendant to ask what he got out of this plot of land.
'Aches and pains', said the man; 'and that's what Pisistratus ought to have his tenth of. The man spoke
without knowing who his questioner was; but Pisistratus was so leased with his frank speech and his industry
that he granted him exemption from all taxes. And so in matters in general he burdened the people as little as
possible with his government, but always cultivated peace and kept them in all quietness. Hence the tyranny
of Pisistratus was often spoken of proverbially as 'the age of gold'; for when his sons succeeded him the
government became much harsher. But most important of all in this respect was his popular and kindly
disposition. In all things he was accustomed to observe the laws, without giving himself any exceptional
privileges. Once he was summoned on a charge of homicide before the Areopagus, and he appeared in person
to make his defence; but the prosecutor was afraid to present himself and abandoned the case. For these
reasons he held power long, and whenever he was expelled he regained his position easily. The majority alike
of the upper class and of the people were in his favour; the former he won by his social intercourse with
them, the latter by the assistance which he gave to their private purses, and his nature fitted him to win the
hearts of both. Moreover, the laws in reference to tyrants at that time in force at Athens were very mild,
especially the one which applies more particularly to the establishment of a tyranny. The law ran as follows:
'These are the ancestral statutes of the ATHENIANS; if any persons shall make an attempt to establish a
tyranny, or if any person shall join in setting up a tyranny, he shall lose his civic rights, both himself and his
whole house.'

Thus did Pisistratus grow old in the possession of power, and he died a natural death in the archonship of
Philoneos, three and thirty years from the time at which he first established himself as tyrant, during nineteen
of which he was in possession of power; the rest he spent in exile. It is evident from this that the story is mere
gossip which states that Pisistratus was the youthful favourite of Solon and commanded in the war against
Megara for the recovery of Salamis. It will not harmonize with their respective ages, as any one may see who
will reckon up the years of the life of each of them, and the dates at which they died. After the death of
Pisistratus his sons took up the government, and conducted it on the same system. He had two sons by his
first and legitimate wife, Hippias and Hipparchus, and two by his Argive consort, Iophon and Hegesistratus,
who was surnamed Thessalus. For Pisistratus took a wife from Argos, Timonassa, the daughter of a man of
Argos, named Gorgilus; she had previously been the wife of Archinus of Ambracia, one of the descendants of
Cypselus. This was the origin of his friendship with the Argives, on account of which a thousand of them
were brought over by Hegesistratus and fought on his side in the battle at Pallene. Some authorities say that
this marriage took place after his first expulsion from Athens, others while he was in possession of the
government.

Hippias and Hipparchus assumed the control of affairs on grounds alike of standing and of age; but Hippias,
as being also naturally of a statesmanlike and shrewd disposition, was really the head of the government.

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THE ATHENIAN CONSTITUTION

Hipparchus was youthful in disposition, amorous, and fond of literature (it was he who invited to Athens
Anacreon, Simonides, and the other poets), while Thessalus was much junior in age, and was violent and
headstrong in his behaviour. It was from his character that all the evils arose which befell the house. He
became enamoured of Harmodius, and, since he failed to win his affection, he lost all restraint upon his
passion, and in addition to other exhibitions of rage he finally prevented the sister of Harmodius from taking
the part of a basket-bearer in the Panathenaic procession, alleging as his reason that Harmodius was a person
of loose life. Thereupon, in a frenzy of wrath, Harmodius and Aristogeiton did their celebrated deed, in
conjunction with a number of confederates. But while they were lying in wait for Hippias in the Acropolis at
the time of the Panathenaea (Hippias, at this moment, was awaiting the arrival of the procession, while
Hipparchus was organizing its dispatch) they saw one of the persons privy to the plot talking familiarly with
him. Thinking that he was betraying them, and desiring to do something before they were arrested, they
rushed down and made their attempt without waiting for the rest of their confederates. They succeeded in
killing Hipparchus near the Leocoreum while he was engaged in arranging the procession, but ruined the
design as a whole; of the two leaders, Harmodius was killed on the spot by the guards, while Aristogeiton
was arrested, and perished later after suffering long tortures. While under the torture he accused many
persons who belonged by birth to the most distinguished families and were also personal friends of the
tyrants. At first the government could find no clue to the conspiracy; for the current story, that Hippias made
all who were taking part in the procession leave their arms, and then detected those who were carrying secret
daggers, cannot be true, since at that time they did not bear arms in the processions, this being a custom
instituted at a later period by the democracy. According to the story of the popular party, Aristogeiton
accused the friends of the tyrants with the deliberate intention that the latter might commit an impious act,
and at the same time weaken themselves, by putting to death innocent men who were their own friends;
others say that he told no falsehood, but was betraying the actual accomplices. At last, when for all his efforts
he could not obtain release by death, he promised to give further information against a number of other
persons; and, having induced Hippias to give him his hand to confirm his word, as soon as he had hold of it
he reviled him for giving his hand to the murderer of his brother, till Hippias, in a frenzy of rage, lost control
of himself and snatched out his dagger and dispatched him.

After this event the tyranny became much harsher. In consequence of his vengeance for his brother, and of
the execution and banishment of a large number of persons, Hippias became a distrusted and an embittered
man. About three years after the death of Hipparchus, finding his position in the city insecure, he set about
fortifying Munichia, with the intention of establishing himself there. While he was still engaged on this work,
however, he was expelled by Cleomenes, king of Lacedaemon, in consequence of the Spartans being
continually incited by oracles to overthrow the tyranny. These oracles were obtained in the following way.
The Athenian exiles, headed by the Alcmeonidae, could not by their own power effect their return, but failed
continually in their attempts. Among their other failures, they fortified a post in Attica, Lipsydrium, above
Mt. Parnes, and were there joined by some partisans from the city; but they were besieged by the tyrants and
reduced to surrender. After this disaster the following became a popular drinking song:

Ah! Lipsydrium, faithless friend!

Lo, what heroes to death didst send,

Nobly born and great in deed!

Well did they prove themselves at need

Of noble sires a noble seed.

19 11

THE ATHENIAN CONSTITUTION

Having failed, then, in very other method, they took the contract for rebuilding the temple at Delphi, thereby
obtaining ample funds, which they employed to secure the help of the Lacedaemonians. All this time the
Pythia kept continually enjoining on the Lacedaemonians who came to consult the oracle, that they must free
Athens; till finally she succeeded in impelling the Spartans to that step, although the house of Pisistratus was
connected with them by ties of hospitality. The resolution of the Lacedaemonians was, however, at least
equally due to the friendship which had been formed between the house of Pisistratus and Argos.
Accordingly they first sent Anchimolus by sea at the head of an army; but he was defeated and killed,
through the arrival of Cineas of Thessaly to support the sons of Pisistratus with a force of a thousand
horsemen. Then, being roused to anger by this disaster, they sent their king, Cleomenes, by land at the head
of a larger force; and he, after defeating the Thessalian cavalry when they attempted to intercept his march
into Attica, shut up Hippias within what was known as the Pelargic wall and blockaded him there with the
assistance of the Athenians. While he was sitting down before the place, it so happened that the sons of the
Pisistratidae were captured in an attempt to slip out; upon which the tyrants capitulated on condition of the
safety of their children, and surrendered the Acropolis to the Athenians, five days being first allowed them to
remove their effects. This took place in the archonship of Harpactides, after they had held the tyranny for
about seventeen years since their father's death, or in all, including the period of their father's rule, for
nine-and-forty years.

After the overthrow of the tyranny, the rival leaders in the state were Isagoras son of Tisander, a partisan of
the tyrants, and Cleisthenes, who belonged to the family of the Alcmeonidae. Cleisthenes, being beaten in the
political clubs, called in the people by giving the franchise to the masses. Thereupon Isagoras, finding himself
left inferior in power, invited Cleomenes, who was united to him by ties of hospitality, to return to Athens,
and persuaded him to 'drive out the pollution', a plea derived from the fact that the Alcmeonidae were
suppposed to be under the curse of pollution. On this Cleisthenes retired from the country, and Cleomenes,
entering Attica with a small force, expelled, as polluted, seven hundred Athenian families. Having effected
this, he next attempted to dissolve the Council, and to set up Isagoras and three hundred of his partisans as the
supreme power in the state. The Council, however, resisted, the populace flocked together, and Cleomenes
and Isagoras, with their adherents, took refuge in the Acropolis. Here the people sat down and besieged them
for two days; and on the third they agreed to let Cleomenes and all his followers de art, while they summoned
Cleisthenes and the other exiles back to Athens. When the people had thus obtained the command of affairs,
Cleisthenes was their chief and popular leader. And this was natural; for the Alcmeonidae were perhaps the
chief cause of the expulsion of the tyrants, and for the greater part of their rule were at perpetual war with
them. But even earlier than the attempts of the Alcmeonidae, one Cedon made an attack on the tyrants; when
there came another popular drinking song, addressed to him:

Pour a health yet again, boy, to Cedon; forget not this duty to do,

If a health is an honour befitting the name of a good man and true.

The people, therefore, had good reason to place confidence in Cleisthenes. Accordingly, now that he was the
popular leader, three years after the expulsion of the tyrants, in the archonship of Isagoras, his first step was
to distribute the whole population into ten tribes in place of the existing four, with the object of intermixing
the members of the different tribes, and so securing that more persons might have a share in the franchise.
From this arose the saying 'Do not look at the tribes', addressed to those who wished to scrutinize the lists of
the old families. Next he made the Council to consist of five hundred members instead of four hundred, each
tribe now contributing fifty, whereas formerly each had sent a hundred. The reason why he did not organize

20 12

THE ATHENIAN CONSTITUTION

the people into twelve tribes was that he might not have to use the existing division into trittyes; for the four
tribes had twelve trittyes, so that he would not have achieved his object of redistributing the population in
fresh combinations. Further, he divided the country into thirty groups of demes, ten from the districts about
the city, ten from the coast, and ten from the interior. These he called trittyes; and he assigned three of them
by lot to each tribe, in such a way that each should have one portion in each of these three localities. All who
lived in any given deme he declared fellow-demesmen, to the end that the new citizens might not be exposed
by the habitual use of family names, but that men might be officially described by the names of their demes;
and accordingly it is by the names of their demes that the Athenians speak of one another. He also instituted
Demarchs, who had the same duties as the previously existing Naucrari,-the demes being made to take the
place of the naucraries. He gave names to the demes, some from the localities to which they belonged, some
from the persons who founded them, since some of the areas no longer corresponded to localities possessing
names. On the other hand he allowed every one to retain his family and clan and religious rites according to
ancestral custom. The names given to the tribes were the ten which the Pythia appointed out of the hundred
selected national heroes.

By these reforms the constitution became much more democratic than that of Solon. The laws of Solon had
been obliterated by disuse during the period of the tyranny, while Cleisthenes substituted new ones with the
object of securing the goodwill of the masses. Among these was the law concerning ostracism. Four year
after the establishment of this system, in the archonship of Hermocreon, they first imposed upon the Council
of Five Hundred the oath which they take to the present day. Next they began to elect the generals by tribes,
one from each tribe, while the Polemarch was the commander of the whole army. Then, eleven years later, in
the archonship of Phaenippus they won the battle of Marathon; and two years after this victory, when the
people had now gained self-confidence, they for the first time made use of the law of ostracism. This had
originally been passed as a precaution against men in high office, because Pisistratus took advantage of his
position as a popular leader and general to make himself tyrant; and the first person ostracized was one of his
relatives, Hipparchus son of Charmus, of the deme of Collytus, the very person on whose account especially
Cleisthenes had enacted the law, as he wished to get rid of him. Hitherto, however, he had escaped; for the
Athenians, with the usual leniency of the democracy, allowed all the partisans of the tyrants, who had not
joined in their evil deeds in the time of the troubles to remain in the city; and the chief and leader of these was
Hipparchus. Then in the very next year, in the archonship of Telesinus, they for the first time since the
tyranny elected, tribe by tribe, the nine Archons by lot out of the five hundred candidates selected by the
demes, all the earlier ones having been elected by vote; and in the same year Megacles son of Hippocrates, of
the deme of Alopece, was ostracized. Thus for three years they continued to ostracize the friends of the
tyrants, on whose account the law had been passed; but in the following year they began to remove others as
well, including any one who seemed to be more powerful than was expedient. The first person unconnected
with the tyrants who was ostracized was Xanthippus son of Ariphron. Two years later, in the archonship of
Nicodemus, the mines of Maroneia were discovered, and the state made a profit of a hundred talents from the
working of them. Some persons advised the people to make a distribution of the money among themselves,
but this was prevented by Themistocles. He refused to say on what he proposed to spend the money, but he
bade them lend it to the hundred richest men in Athens, one talent to each, and then, if the manner in which it
was employed pleased the people, the expenditure should be charged to the state, but otherwise the state
should receive the sum back from those to whom it was lent. On these terms he received the money and with
it he had a hundred triremes built, each of the hundred individuals building one; and it was with these ships
that they fought the battle of Salamis against the barbarians. About this time Aristides the son of Lysimachus
was ostracized. Three years later, however, in the archonship of Hypsichides, all the ostracized persons were
recalled, on account of the advance of the army of Xerxes; and it was laid down for the future that persons
under sentence of ostracism must live between Geraestus and Scyllaeum, on pain of losing their civic rights
irrevocably.

22 13

THE ATHENIAN CONSTITUTION

So far, then, had the city progressed by this time, growing gradually with the growth of the democracy; but
after the Persian wars the Council of Areopagus once more developed strength and assumed the control of the
state. It did not acquire this supremacy by virtue of any formal decree, but because it had been the cause of
the battle of Salamis being fought. When the generals were utterly at a loss how to meet the crisis and made
proclamation that every one should see to his own safety, the Areopagus provided a donation of money,
distributing eight drachmas to each member of the ships' crews, and so prevailed on them to go on board. On
these grounds people bowed to its prestige; and during this period Athens was well administered. At this time
they devoted themselves to the prosecution of the war and were in high repute among the Greeks, so that the
command by sea was conferred upon them, in spite of the opposition of the Lacedaemonians. The leaders of
the people during this period were Aristides, of Lysimachus, and Themistocles, son of Lysimachus, and
Themistocles, son of Neocles, of whom the latter appeared to devote himself to the conduct of war, while the
former had the reputation of being a clever statesman and the most upright man of his time. Accordingly the
one was usually employed as general, the other as political adviser. The rebuilding of the fortifications they
conducted in combination, although they were political opponents; but it was Aristides who, seizing the
opportunity afforded by the discredit brought upon the Lacedaemonians by Pausanias, guided the public
policy in the matter of the defection of the Ionian states from the alliance with Sparta. It follows that it was he
who made the first assessment of tribute from the various allied states, two years after the battle of Salamis,
in the archonship of Timosthenes; and it was he who took the oath of offensive and defensive alliance with
the Ionians, on which occasion they cast the masses of iron into the sea.

After this, seeing the state growing in confidence and much wealth accumulated, he advised the people to lay
hold of the leadership of the league, and to quit the country districts and settle in the city. He pointed out to
them that all would be able to gain a living there, some by service in the army, others in the garrisons, others
by taking a part in public affairs; and in this way they would secure the leadership. This advice was taken;
and when the people had assumed the supreme control they proceeded to treat their allies in a more imperious
fashion, with the exception of the Chians, Lesbians, and Samians. These they maintained to protect their
empire, leaving their constitutions untouched, and allowing them to retain whatever dominion they then
possessed. They also secured an ample maintenance for the mass of the population in the way which
Aristides had pointed out to them. Out of the proceeds of the tributes and the taxes and the contributions of
the allies more than twenty thousand persons were maintained. There were 6,000 jurymen, 1,600 bowmen,
1,200 Knights, 500 members of the Council, 500 guards of the dockyards, besides fifty guards in the
Acropolis. There were some 700 magistrates at home, and some 700 abroad. Further, when they subsequently
went to war, there were in addition 2,500 heavy-armed troops, twenty guard-ships, and other ships which
collected the tributes, with crews amounting to 2,000 men, selected by lot; and besides these there were the
persons maintained at the Prytaneum, and orphans, and gaolers, since all these were supported by the state.

Such was the way in which the people earned their livelihood. The supremacy of the Areopagus lasted for
about seventeen years after the Persian wars, although gradually declining. But as the strength of the masses
increased, Ephialtes, son of Sophonides, a man with a reputation for incorruptibility and public virtue, who
had become the leader of the people, made an attack upon that Council. First of all he ruined many of its
members by bringing actions against them with reference to their administration. Then, in the archonship of
Conon, he stripped the Council of all the acquired prerogatives from which it derived its guardianship of the
constitution, and assigned some of them to the Council of Five Hundred, and others to the Assembly and the
law-courts. In this revolution he was assisted by Themistocles, who was himself a member of the Areopagus,

23 14

THE ATHENIAN CONSTITUTION

but was expecting to be tried before it on a charge of treasonable dealings with Persia. This made him
anxious that it should be overthrown, and accordingly he warned Ephialtes that the Council intended to arrest
him, while at the same time he informed the Areopagites that he would reveal to them certain persons who
were conspiring to subvert the constitution. He then conducted the representatives delegated by the Council
to the residence of Ephialtes, promising to show them the conspirators who assembled there, and proceeded
to converse with them in an earnest manner. Ephialtes, seeing this, was seized with alarm and took refuge in
suppliant guise at the altar. Every one was astounded at the occurrence, and presently, when the Council of
Five Hundred met, Ephialtes and Themistocles together proceeded to denounce the Areopagus to them. This
they repeated in similar fashion in the Assembly, until they succeeded in depriving it of its power. Not long
afterwards, however, Ephialtes was assassinated by Aristodicus of Tanagra. In this way was the Council of
Areopagus deprived of its guardianship of the state.

After this revolution the administration of the state became more and more lax, in consequence of the eager
rivalry of candidates for popular favour. During this period the moderate party, as it happened, had no real
chief, their leader being Cimon son of Miltiades, who was a comparatively young man, and had been late in
entering public life; and at the same time the general populace suffered great losses by war. The soldiers for
active service were selected at that time from the roll of citizens, and as the generals were men of no military
experience, who owed their position solely to their family standing, it continually happened that some two or
three thousand of the troops perished on an expedition; and in this way the best men alike of the lower and
the upper classes were exhausted. Consequently in most matters of administration less heed was paid to the
laws than had formerly been the case. No alteration, however, was made in the method of election of the nine
Archons, except that five years after the death of Ephialtes it was decided that the candidates to be submitted
to the lot for that office might be selected from the Zeugitae as well as from the higher classes. The first
Archon from that class was Mnesitheides. Up to this time all the Archons had been taken from the
Pentacosiomedimni and Knights, while the Zeugitae were confined to the ordinary magistracies, save where
an evasion of the law was overlooked. Four years later, in the archonship of Lysicrates, thirty 'local justices',
as they as they were called, were re-established; and two years afterwards, in the archonship of Antidotus,
consequence of the great increase in the number of citizens, it was resolved, on the motion of Pericles, that no
one should admitted to the franchise who was not of citizen birth by both parents.

After this Pericles came forward as popular leader, having first distinguished himself while still a young man
by prosecuting Cimon on the audit of his official accounts as general. Under his auspices the constitution
became still more democratic. He took away some of the privileges of the Areopagus, and, above all, he
turned the policy of the state in the direction of sea power, which caused the masses to acquire confidence in
themselves and consequently to take the conduct of affairs more and more into their own hands. Moreover,
forty-eight years after the battle of Salamis, in the archonship of Pythodorus, the Peloponnesian war broke
out, during which the populace was shut up in the city and became accustomed to gain its livelihood by
military service, and so, partly voluntarily and partly involuntarily, determined to assume the administration
of the state itself. Pericles was also the first to institute pay for service in the law-courts, as a bid for popular
favour to counterbalance the wealth of Cimon. The latter, having private possessions on a regal scale, not
only performed the regular public services magnificently, but also maintained a large number of his
fellow-demesmen. Any member of the deme of Laciadae could go every day to Cimon's house and there
receive a reasonable provision; while his estate was guarded by no fences, so that any one who liked might
help himself to the fruit from it. Pericles' private property was quite unequal to this magnificence and
accordingly he took the advice of Damonides of Oia (who was commonly supposed to be the person who
prompted Pericles in most of his measures, and was therefore subsequently ostracized), which was that, as he

26 15

THE ATHENIAN CONSTITUTION

was beaten in the matter of private possessions, he should make gifts to the people from their own property;
and accordingly he instituted pay for the members of the juries. Some critics accuse him of thereby causing a
deterioration in the character of the juries, since it was always the common people who put themselves
forward for selection as jurors, rather than the men of better position. Moreover, bribery came into existence
after this, the first person to introduce it being Anytus, after his command at Pylos. He was prosecuted by
certain individuals on account of his loss of Pylos, but escaped by bribing the jury.

So long, however, as Pericles was leader of the people, things went tolerably well with the state; but when he
was dead there was a great change for the worse. Then for the first time did the people choose a leader who
was of no reputation among men of good standing, whereas up to this time such men had always been found
as leaders of the democracy. The first leader of the people, in the very beginning of things, was Solon, and
the second was Pisistratus, both of them men of birth and position. After the overthrow of the tyrants there
was Cleisthenes, a member of the house of the Alcmeonidae; and he had no rival opposed to him after the
expulsion of the party of Isagoras. After this Xanthippus was the leader of the people, and Miltiades of the
upper class. Then came Themistocles and Aristides, and after them Ephialtes as leader of the people, and
Cimon son of Miltiades of the wealthier class. Pericles followed as leader of the people, and Thucydides, who
was connected by marriage with Cimon, of the opposition. After the death of Pericles, Nicias, who
subsequently fell in Sicily, appeared as leader of the aristocracy, and Cleon son of Cleaenetus of the people.
The latter seems, more than any one else, to have been the cause of the corruption of the democracy by his
wild undertakings; and he was the first to use unseemly shouting and coarse abuse on the Bema, and to
harangue the people with his cloak girt up short about him, whereas all his predecessors had spoken decently
and in order. These were succeeded by Theramenes son of Hagnon as leader of the one party, and the
lyre-maker Cleophon of the people. It was Cleophon who first granted the twoobol donation for the theatrical
performances, and for some time it continued to be given; but then Callicrates of Paeania ousted him by
promising to add a third obol to the sum. Both of these persons were subsequently condemned to death; for
the people, even if they are deceived for a time, in the end generally come to detest those who have beguiled
them into any unworthy action. After Cleophon the popular leadership was occupied successively by the men
who chose to talk the biggest and pander the most to the tastes of the majority, with their eyes fixed only on
the interests of the moment. The best statesmen at Athens, after those of early times, seem to have been
Nicias, Thucydides, and Theramenes. As to Nicias and Thucydides, nearly every one agrees that they were
not merely men of birth and character, but also statesmen, and that they ruled the state with paternal care. On
the merits of Theramenes opinion is divided, because it so happened that in his time public affairs were in a
very stormy state. But those who give their opinion deliberately find him, not, as his critics falsely assert,
overthrowing every kind of constitution, but supporting every kind so long as it did not transgress laws; thus
showing that he was able, as every good citizen should be, to live under any form of constitution, while he
refused to countenance illegality and was its constant enemy.

So long as the fortune of the war continued even, the Athenians preserved the democracy; but after the
disaster in Sicily, when the Lacedaemonians had gained the upper hand through their alliance with the king of
Persia, they were compelled to abolish the democracy and establish in its place the constitution of the Four
Hundred. The speech recommending this course before the vote was made by Melobius, and the motion was
proposed by Pythodorus of Anaphlystus; but the real argument which persuaded the majority was the belief
that the king of Persia was more likely to form an alliance with them if the constitution were on an
oligarchical basis. The motion of Pythodorus was to the following effect. The popular Assembly was to elect
twenty persons, over forty years of age, who, in conjunction with the existing ten members of the Committee
of Public Safety, after taking an oath that they would frame such measures as they thought best for the state,

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THE ATHENIAN CONSTITUTION

should then prepare proposals for the public, safety. In addition, any other person might make proposals, so
that of all the schemes before them the people might choose the best. Cleitophon concurred with the motion
of Pythodorus, but moved that the committee should also investigate the ancient laws enacted by Cleisthenes
when he created the democracy, in order that they might have these too before them and so be in a position to
decide wisely; his suggestion being that the constitution of Cleisthenes was not really democratic, but closely
akin to that of Solon. When the committee was elected, their first proposal was that the Prytanes should be
compelled to put to the vote any motion that was offered on behalf of the public safety. Next they abolished
all indictments for illegal proposals, all impeachments and pubic prosecutions, in order that every Athenian
should be free to give his counsel on the situation, if he chose; and they decreed that if any person imposed a
fine on any other for his acts in this respect, or prosecuted him or summoned him before the courts, he
should, on an information being laid against him, be summarily arrested and brought before the generals, who
should deliver him to the Eleven to be put to death. After these preliminary measures, they drew up the
constitution in the following manner. The revenues of the state were not to be spent on any purpose except
the war. All magistrates should serve without remuneration for the period of the war, except the nine Archons
and the Prytanes for the time being, who should each receive three obols a day. The whole of the rest of the
administration was to be committed, for the period of the war, to those Athenians who were most capable of
serving the state personally or pecuniarily, to the number of not less than five thousand. This body was to
have full powers, to the extent even of making treaties with whomsoever they willed; and ten representatives,
over forty years of age, were to be elected from each tribe to draw up the list of the Five Thousand, after
taking an oath on a full and perfect sacrifice.

These were the recommendations of the committee; and when they had been ratified the Five Thousand
elected from their own number a hundred commissioners to draw up the constitution. They, on their
appointment, drew up and produced the following recommendations. There should be a Council, holding
office for a year, consisting of men over thirty years of age, serving without pay. To this body should belong
the Generals, the nine Archons, the Amphictyonic Registrar (Hieromnemon), the Taxiarchs, the Hipparchs,
the Phylarch, the commanders of garrisons, the Treasurers of Athena and the other gods, ten in number, the
Hellenic Treasurers (Hellenotamiae), the Treasurers of the other non-sacred moneys, to the number of
twenty, the ten Commissioners of Sacrifices (Hieropoei), and the ten Superintendents of the mysteries. All
these were to be appointed by the Council from a larger number of selected candidates, chosen from its
members for the time being. The other offices were all to be filled by lot, and not from the members of the
Council. The Hellenic Treasurers who actually administered the funds should not sit with the Council. As
regards the future, four Councils were to be created, of men of the age already mentioned, and one of these
was to be chosen by lot to take office at once, while the others were to receive it in turn, in the order decided
by the lot. For this purpose the hundred commissioners were to distribute themselves and all the rest as
equally as possible into four parts, and cast lots for precedence, and the selected body should hold office for a
year. They were to administer that office as seemed to them best, both with reference to the safe custody and
due expenditure of the finances, and generally with regard to all other matters to the best of their ability. If
they desired to take a larger number of persons into counsel, each member might call in one assistant of his
own choice, subject to the same qualification of age. The Council was to sit once every five days, unless there
was any special need for more frequent sittings. The casting of the lot for the Council was to be held by the
nine Archons; votes on divisions were to be counted by five tellers chosen by lot from the members of the
Council, and of these one was to be selected by lot every day to act as president. These five persons were to
cast lots for precedence between the parties wishing to appear before the Council, giving the first place to
sacred matters, the second to heralds, the third to embassies, and the fourth to all other subjects; but matters
concerning the war might be dealt with, on the motion of the generals, whenever there was need, without
balloting. Any member of the Council who did not enter the Council-house at the time named should be
fined a drachma for each day, unless he was away on leave of absence from the Council.

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THE ATHENIAN CONSTITUTION

Such was the constitution which they drew up for the time to come, but for the immediate present they
devised the following scheme. There should be a Council of Four Hundred, as in the ancient constitution,
forty from each tribe, chosen out of candidates of more than thirty years of age, selected by the members of
the tribes. This Council should appoint the magistrates and draw up the form of oath which they were to take;
and in all that concerned the laws, in the examination of official accounts, and in other matters generally, they
might act according to their discretion. They must, however, observe the laws that might be enacted with
reference to the constitution of the state, and had no power to alter them nor to pass others. The generals
should be provisionally elected from the whole body of the Five Thousand, but so soon as the Council came
into existence it was to hold an examination of military equipments, and thereon elect ten persons, together
with a secretary, and the persons thus elected should hold office during the coming year with full powers, and
should have the right, whenever they desired it, of joining in the deliberations of the Council. The Five
thousand was also to elect a single Hipparch and ten Phylarchs; but for the future the Council was to elect
these officers according to the regulations above laid down. No office, except those of member of the Council
and of general, might be held more than once, either by the first occupants or by their successors. With
reference to the future distribution of the Four Hundred into the four successive sections, the hundred
commissioners must divide them whenever the time comes for the citizens to join in the Council along with
the rest.

The hundred commissioners appointed by the Five Thousand drew up the constitution as just stated; and after
it had been ratified by the people, under the presidency of Aristomachus, the existing Council, that of the year
of Callias, was dissolved before it had completed its term of office. It was dissolved on the fourteenth day of
the month Thargelion, and the Four Hundred entered into office on the twenty-first; whereas the regular
Council, elected by lot, ought to have entered into office on the fourteenth of Scirophorion. Thus was the
oligarchy established, in the archonship of Callias, just about a hundred years after the expulsion of the
tyrants. The chief promoters of the revolution were Pisander, Antiphon, and Theramenes, all of them men of
good birth and with high reputations for ability and judgement. When, however, this constitution had been
established, the Five Thousand were only nominally selected, and the Four Hundred, together with the ten
officers on whom full powers had been conferred, occupied the Council-house and really administered the
government. They began by sending ambassadors to the Lacedaemonians proposing a cessation of the war on
the basis of the existing Position; but as the Lacedaemonians refused to listen to them unless they would also
abandon the command of the sea, they broke off the negotiations.

For about four months the constitution of the Four Hundred lasted, and Mnasilochus held office as Archon of
their nomination for two months of the year of Theopompus, who was Archon for the remaining ten. On the
loss of the naval battle of Eretria, however, and the revolt of the whole of Euboea except Oreum, the
indignation of the people was greater than at any of the earlier disasters, since they drew far more supplies at
this time from Euboea than from Attica itself. Accordingly they deposed the Four Hundred and committed
the management of affairs to the Five Thousand, consisting of persons Possessing a military equipment. At
the same time they voted that pay should not be given for any public office. The persons chiefly responsible
for the revolution were Aristocrates and Theramenes, who disapproved of the action of the Four Hundred in
retaining the direction of affairs entirely in their own hands, and referring nothing to the Five Thousand.
During this period the constitution of the state seems to have been admirable, since it was a time of war and
the franchise was in the hands of those who possessed a military equipment.

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THE ATHENIAN CONSTITUTION

The people, however, in a very short time deprived the Five Thousand of their monopoly of the government.
Then, six years after the overthrow of the Four Hundred, in the archonship of Callias of Angele, battle of
Arginusae took place, of which the results were, first, that the ten generals who had gained the victory were
all condemned by a single decision, owing to the people being led astray by persons who aroused their
indignation; though, as a matter of fact, some of the generals had actually taken no part in the battle, and
others were themselves picked up by other vessels. Secondly, when the Lacedaemonians proposed to
evacuate Decelea and make peace on the basis of the existing position, although some of the Athenians
supported this proposal, the majority refused to listen to them. In this they were led astray by Cleophon, who
appeared in the Assembly drunk and wearing his breastplate, and prevented peace being made, declaring that
he would never accept peace unless the Lacedaemoniof the whole of Euboea except Oreum, the indignation
of the peoans abandoned their claims on all the cities allied with them. They mismanaged their opportunity
then, and in a very short time they learnt their mistake. The next year, in the archonship of Alexias, they
suffered the disaster of Aegospotami, the consequence of which was that Lysander became master of the city,
and set up the Thirty as its governors. He did so in the following manner. One of the terms of peace stipulated
that the state should be governed according to 'the ancient constitution'. Accordingly the popular party tried to
preserve the democracy, while that part of the upper class which belonged to the political clubs, together with
the exiles who had returned since the peace, aimed at an oligarchy, and those who were not members of any
club, though in other respects they considered themselves as good as any other citizens, were anxious to
restore the ancient constitution. The latter class included Archinus, Anytus, Cleitophon, Phormisius, and
many others, but their most prominent leader was Theramenes. Lysander, however, threw his influence on the
side of the oligarchical party, and the popular Assembly was compelled by sheer intimidation to pass a vote
establishing the oligarchy. The motion to this effect was proposed by Dracontides of Aphidna.

In this way were the Thirty established in power, in the archonship of Pythodorus. As soon, however, as they
were masters of the city, they ignored all the resolutions which had been passed relating to the organization of
the constitution, but after appointing a Council of Five Hundred and the other magistrates out of a thousand
selected candidates, and associating with themselves ten Archons in Piraeus, eleven superintendents of the
prison, and three hundred 'lash-bearers' as attendants, with the help of these they kept the city under their
own control. At first, indeed, they behaved with moderation towards the citizens and pretended to administer
the state according to the ancient constitution. In pursuance of this policy they took down from the hill of
Areopagus the laws of Ephialtes and Archestratus relating to the Areopagite Council; they also repealed such
of the statutes of Solon as were obscure, and abolished the supreme power of the law-courts. In this they
claimed to be restoring the constitution and freeing it from obscurities; as, for instance, by making the testator
free once for all to leave his property as he pleased, and abolishing the existing limitations in cases of
insanity, old age, and undue female influence, in order that no opening might be left for professional
accusers. In other matters also their conduct was similar. At first, then, they acted on these lines, and they
destroyed the professional accusers and those mischievous and evil-minded persons who, to the great
detriment of the democracy, had attached themselves to it in order to curry favour with it. With all of this the
city was much pleased, and thought that the Thirty were doing it with the best of motives. But so soon as they
had got a firmer hold on the city, they spared no class of citizens, but put to death any persons who were
eminent for wealth or birth or character. Herein they aimed at removing all whom they had reason to fear,
while they also wished to lay hands on their possessions; and in a short time they put to death not less than
fifteen hundred persons.

34 19

THE ATHENIAN CONSTITUTION

Theramenes, however, seeing the city thus falling into ruin, was displeased with their proceedings, and
counselled them to cease such unprincipled conduct and let the better classes have a share in the government.
At first they resisted his advice, but when his proposals came to be known abroad, and the masses began to
associate themselves with him, they were seized with alarm lest he should make himself the leader of the
people and destroy their despotic power. Accordingly they drew up a list of three thousand citizens, to whom
they announced that they would give a share in the constitution. Theramenes, however, criticized this scheme
also, first on the ground that, while proposing to give all respectable citizens a share in the constitution, they
were actually giving it only to three thousand persons, as though all merit were confined within that number;
and secondly because they were doing two inconsistent things, since they made the government rest on the
basis of force, and yet made the governors inferior in strength to the governed. However, they took no notice
of his criticisms, and for a long time put off the publication of the list of the Three Thousand and kept to
themselves the names of those who had been placed upon it; and every time they did decide to publish it they
proceeded to strike out some of those who had been included in it, and insert others who had been omitted.

Now when winter had set in, Thrasybulus and the exiles occupied Phyle, and the force which the Thirty led
out to attack them met with a reverse. Thereupon the Thirty decided to disarm the bulk of the population and
to get rid of Theramenes; which they did in the following way. They introduced two laws into the Council,
which they commanded it to pass; the first of them gave the Thirty absolute power to put to death any citizen
who was not included in the list of the Three Thousand, while the second disqualified all persons from
participation in the franchise who should have assisted in the demolition of the fort of Eetioneia, or have
acted in any way against the Four Hundred who had organized the previous oligarchy. Theramenes had done
both, and accordingly, when these laws were ratified, he became excluded from the franchise and the Thirty
had full power to put him to death. Theramenes having been thus removed, they disarmed all the people
except the Three Thousand, and in every respect showed a great advance in cruelty and crime. They also sent
ambassadors to Lacedaemonian to blacken the character of Theramenes and to ask for help; and the
Lacedaemonians, in answer to their appeal, sent Callibius as military governor with about seven hundred
troops, who came and occupied the Acropolis.

These events were followed by the occupation of Munichia by the exiles from Phyle, and their victory over
the Thirty and their partisans. After the fight the party of the city retreated, and next day they held a meeting
in the marketplace and deposed the Thirty, and elected ten citizens with full powers to bring the war to a
termination. When, however, the Ten had taken over the government they did nothing towards the object for
which they were elected, but sent envoys to Lacedaemonian to ask for help and to borrow money. Further,
finding that the citizens who possessed the franchise were displeased at their proceedings, they were afraid
lest they should be deposed, and consequently, in order to strike terror into them (in which design they
succeeded), they arrested Demaretus, one of the most eminent citizens, and put him to death. This gave them
a firm hold on the government, and they also had the support of Callibius and his Peloponnesians, together
with several of the Knights; for some of the members of this class were the most zealous among the citizens
to prevent the return of the exiles from Phyle. When, however, the party in Piraeus and Munichia began to
gain the upper hand in the war, through the defection of the whole populace to them, the party in the city
deposed the original Ten, and elected another Ten, consisting of men of the highest repute. Under their
administration, and with their active and zealous cooperation, the treaty of reconciliation was made and the
populace returned to the city. The most prominent members of this board were Rhinon of Paeania and
Phayllus of Acherdus, who, even before the arrival of Pausanias, opened negotiations with the party in

36 20

THE ATHENIAN CONSTITUTION

Piraeus, and after his arrival seconded his efforts to bring about the return of the exiles. For it was Pausanias,
the king of the Lacedaemonians, who brought the peace and reconciliation to a fulfillment, in conjunction
with the ten commissioners of arbitration who arrived later from Lacedaemonian, at his own earnest request.
Rhinon and his colleagues received a vote of thanks for the goodwill shown by them to the people, and
though they received their charge under an oligarchy and handed in their accounts under a democracy, no
one, either of the party that had stayed in the city or of the exiles that had returned from the Piraeus, brought
any complaint against them. On the contrary, Rhinon was immediately elected general on account of his
conduct in this office.

This reconciliation was effected in the archonship of Eucleides, on the following terms. All persons who,
having remained in the city during the troubles, were now anxious to leave it, were to be free to settle at
Eleusis, retaining their civil rights and possessing full and independent powers of self-government, and with
the free enjoyment of their own personal property. The temple at Eleusis should be common ground for both
parties, and should be under the superintendence of the Ceryces, and the Eumolpidae, according to primitive
custom. The settlers at Eleusis should not be allowed to enter Athens, nor the people of Athens to enter
Eleusis, except at the season of the mysteries, when both parties should be free from these restrictions. The
secessionists should pay their share to the fund for the common defence out of their revenues, just like all the
other Athenians. If any of the seceding party wished to take a house in Eleusis, the people would help them to
obtain the consent of the owner; but if they could not come to terms, they should appoint three valuers on
either side, and the owner should receive whatever price they should appoint. Of the inhabitants of Eleusis,
those whom the secessionists wished to remain should be allowed to do so. The list of those who desired to
secede should be made up within ten days after the taking of the oaths in the case of persons already in the
country, and their actual departure should take place within twenty days; persons at present out of the country
should have the same terms allowed to them after their return. No one who settled at Eleusis should be
capable of holding any office in Athens until he should again register himself on the roll as a resident in the
city. Trials for homicide, including all cases in which one party had either killed or wounded another, should
be conducted according to ancestral practice. There should be a general amnesty concerning past events
towards all persons except the Thirty, the Ten, the Eleven, and the magistrates in Piraeus; and these too
should be included if they should submit their accounts in the usual way. Such accounts should be given by
the magistrates in Piraeus before a court of citizens rated in Piraeus, and by the magistrates in the city before
a court of those rated in the city. On these terms those who wished to do so might secede. Each party was to
repay separately the money which it had borrowed for the war.

When the reconciliation had taken place on these terms, those who had fought on the side of the Thirty felt
considerable apprehensions, and a large number intended to secede. But as they put off entering their names
till the last moment, as people will do, Archinus, observing their numbers, and being anxious to retain them
as citizens, cut off the remaining days during which the list should have remained open; and in this way many
persons were compelled to remain, though they did so very unwillingly until they recovered confidence. This
is one point in which Archinus appears to have acted in a most statesmanlike manner, and another was his
subsequent prosecution of Thrasybulus on the charge of illegality, for a motion by which he proposed to
confer the franchise on all who had taken part in the return from Piraeus, although some of them were
notoriously slaves. And yet a third such action was when one of the returned exiles began to violate the
amnesty, whereupon Archinus haled him to the Council and persuaded them to execute him without trial,
telling them that now they would have to show whether they wished to preserve the democracy and abide by
the oaths they had taken; for if they let this man escape they would encourage others to imitate him, while if
they executed him they would make an example for all to learn by. And this was exactly what happened; for

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THE ATHENIAN CONSTITUTION

after this man had been put to death no one ever again broke the amnesty. On the contrary, the Athenians
seem, both in public and in private, to have behaved in the most unprecedentedly admirable and
public-spirited way with reference to the preceding troubles. Not only did they blot out all memory of former
offences, but they even repaid to the Lacedaemonians out of the public purse the money which the Thirty had
borrowed for the war, although the treaty required each party, the party of the city and the party of Piraeus, to
pay its own debts separately. This they did because they thought it was a necessary first step in the direction
of restoring harmony; but in other states, so far from the democratic parties making advances from their own
possessions, they are rather in the habit of making a general redistribution of the land. A final reconciliation
was made with the secessionists at Eleusis two years after the secession, in the archonship of Xenaenetus.

This, however, took place at a later date; at the time of which we are speaking the people, having secured the
control of the state, established the constitution which exists at the present day. Pythodorus was Archon at the
time, but the democracy seems to have assumed the supreme power with perfect justice, since it had effected
its own return by its own exertions. This was the eleventh change which had taken place in the constitution of
Athens. The first modification of the primaeval condition of things was when Ion and his companions
brought the people together into a community, for then the people was first divided into the four tribes, and
the tribe-kings were created. Next, and first after this, having now some semblance of a constitution, was that
which took place in the reign of Theseus, consisting in a slight deviation from absolute monarchy. After this
came the constitution formed under Draco, when the first code of laws was drawn up. The third was that
which followed the civil war, in the time of Solon; from this the democracy took its rise. The fourth was the
tyranny of Pisistratus; the fifth the constitution of Cleisthenes, after the overthrow of the tyrants, of a more
democratic character than that of Solon. The sixth was that which followed on the Persian wars, when the
Council of Areopagus had the direction of the state. The seventh, succeeding this, was the constitution which
Aristides sketched out, and which Ephialtes brought to completion by overthrowing the Areopagite Council;
under this the nation, misled by the demagogues, made the most serious mistakes in the interest of its
maritime empire. The eighth was the establishment of the Four Hundred, followed by the ninth, the restored
democracy. The tenth was the tyranny of the Thirty and the Ten. The eleventh was that which followed the
return from Phyle and Piraeus; and this has continued from that day to this, with continual accretions of
power to the masses. The democracy has made itself master of everything and administers everything by its
votes in the Assembly and by the law-courts, in which it holds the supreme power. Even the jurisdiction of
the Council has passed into the hands of the people at large; and this appears to be a judicious change, since
small bodies are more open to corruption, whether by actual money or influence, than large ones. At first they
refused to allow payment for attendance at the Assembly; but the result was that people did not attend.
Consequently, after the Prytanes had tried many devices in vain in order to induce the populace to come and
ratify the votes, Agyrrhius, in the first instance, made a provision of one obol a day, which Heracleides of
Clazomenae, nicknamed 'the king', increased to two obols, and Agyrrhius again to three.

The present state of the constitution is as follows. The franchise is open to all who are of citizen birth by both
parents. They are enrolled among the demesmen at the age of eighteen. On the occasion of their enrollment
the demesmen give their votes on oath, first whether the candidates appear to be of the age prescribed by the
law (if not, they are dismissed back into the ranks of the boys), and secondly whether the candidate is free
born and of such parentage as the laws require. Then if they decide that he is not a free man, he appeals to the
law-courts, and the demesmen appoint five of their own number to act as accusers; if the court decides that
he has no right to be enrolled, he is sold by the state as a slave, but if he wins his case he has a right to be
enrolled among the demesmen without further question. After this the Council examines those who have been
enrolled, and if it comes to the conclusion that any of them is less than eighteen years of age, it fines the

41 22

THE ATHENIAN CONSTITUTION

demesmen who enrolled him. When the youths (Ephebi) have passed this examination, their fathers meet by
their tribes, and appoint on oath three of their fellow tribesmen, over forty years of age, who, in their opinion,
are the best and most suitable persons to have charge of the youths; and of these the Assembly elects one
from each tribe as guardian, together with a director, chosen from the general body of Athenians, to control
the while. Under the charge of these persons the youths first of all make the circuit of the temples; then they
proceed to Piraeus, and some of them garrison Munichia and some the south shore. The Assembly also elects
two trainers, with subordinate instructors, who teach them to fight in heavy armour, to use the bow and
javelin, and to discharge a catapult. The guardians receive from the state a drachma apiece for their keep, and
the youths four obols apiece. Each guardian receives the allowance for all the members of his tribe and buys
the necessary provisions for the common stock (they mess together by tribes), and generally superintends
everything. In this way they spend the first year. The next year, after giving a public display of their military
evolutions, on the occasion when the Assembly meets in the theatre, they receive a shield and spear from the
state; after which they patrol the country and spend their time in the forts. For these two years they are on
garrison duty, and wear the military cloak, and during this time they are exempt from all taxes. They also can
neither bring an action at law, nor have one brought against them, in order that they may have no excuse for
requiring leave of absence; though exception is made in cases of actions concerning inheritances and wards
of state, or of any sacrificial ceremony connected with the family. When the two years have elapsed they
thereupon take their position among the other citizens. Such is the manner of the enrollment of the citizens
and the training of the youths.

All the magistrates that are concerned with the ordinary routine of administration are elected by lot, except
the Military Treasurer, the Commissioners of the Theoric fund, and the Superintendent of Springs. These are
elected by vote, and hold office from one Panathenaic festival to the next. All military officers are also
elected by vote.

The Council of Five Hundred is elected by lot, fifty from each tribe. Each tribe holds the office of Prytanes in
turn, the order being determined by lot; the first four serve for thirty-six days each, the last six for
thirty-five, since the reckoning is by lunar years. The Prytanes for the time being, in the first place, mess
together in the Tholus, and receive a sum of money from the state for their maintenance; and, secondly, they
convene the meetings of the Council and the Assembly. The Council they convene every day, unless it is a
holiday, the Assembly four times in each prytany. It is also their duty to draw up the programme of the
business of the Council and to decide what subjects are to be dealt with on each particular da, and where the
sitting is to be held. They also draw up the programme for the meetings of the Assembly. One of these in
each prytany is called the 'sovereign' Assembly; in this the people have to ratify the continuance of the
magistrates in office, if they are performing their duties properly, and to consider the supply of corn and the
defence of the country. On this day, too, impeachments are introduced by those who wish to do so, the lists of
property confiscated by the state are read, and also applications for inheritances and wards of state, so that
nothing may pass unclaimed without the cognizance of any person concerned. In the sixth prytany, in
addition to the business already stated, the question is put to the vote whether it is desirable to hold a vote of
ostracism or not; and complaints against professional accusers, whether Athenian or aliens domiciled in
Athens, are received, to the number of not more than three of either class, together with cases in which an
individual has made some promise to the people and has not performed it. Another Assembly in each prytany
is assigned to the hearing of petitions, and at this meeting any one is free, on depositing the petitioner's
olive-branch, to speak to the people concerning any matter, public or private. The two remaining meetings
are devoted to all other subjects, and the laws require them to deal with three questions connected with
religion, three connected with heralds and embassies, and three on secular subjects. Sometimes questions are
brought forward without a preliminary vote of the Assembly to take them into consideration.

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THE ATHENIAN CONSTITUTION

Heralds and envoys appear first before the Prytanes, and the bearers of dispatches also deliver them to the
same officials.

There is a single President of the Prytanes, elected by lot, who presides for a night and a day; he may not hold
the office for more than that time, nor may the same individual hold it twice. He keeps the keys of the
sanctuaries in which the treasures and public records of the state are preserved, and also the public seal; and
he is bound to remain in the Tholus, together with one-third of the Prytanes, named by himself. Whenever
the Prytanes convene a meeting of the Council or Assembly, he appoints by lot nine Proedri, one from each
tribe except that which holds the office of Prytanes for the time being; and out of these nine he similarly
appoints one as President, and hands over the programme for the meeting to them. They take it and see to the
preservation of order, put forward the various subjects which are to be considered, decide the results of the
votings, and direct the proceedings generally. They also have power to dismiss the meeting. No one may act
as President more than once in the year, but he may be a Proedrus once in each prytany.

Elections to the offices of General and Hipparch and all other military commands are held in the Assembly,
in such manner as the people decide; they are held after the sixth prytany by the first board of Prytanes in
whose term of office the omens are favourable. There has, however, to be a preliminary consideration by the
Council in this case also.

In former times the Council had full powers to inflict fines and imprisonment and death; but when it had
consigned Lysimachus to the executioner, and he was sitting in the immediate expectation of death,
Eumelides of Alopece rescued him from its hands, maintaining that no citizen ought to be put to death except
on the decision of a court of law. Accordingly a trial was held in a law-court, and Lysimachus was acquitted,
receiving henceforth the nickname of 'the man from the drum-head'; and the people deprived the Council
thenceforward of the power to inflict death or imprisonment or fine, passing a law that if the Council
condemn any person for an offence or inflict a fine, the Thesmothetae shall bring the sentence or fine before
the law-court, and the decision of the jurors shall be the final judgement in the matter.

The Council passes judgement on nearly all magistrates, especially those who have the control of money; its
judgement, however, is not final, but is subject to an appeal to the lawcourts. Private individuals, also, may
lay an information against any magistrate they please for not obeying the laws, but here too there is an appeal
to the law-courts if the Council declare the charge proved. The Council also examines those who are to be its
members for the ensuing year, and likewise the nine Archons. Formerly the Council had full power to reject
candidates for office as unsuitable, but now they have an appeal to the law-courts. In all these matters,
therefore, the Council has no final jurisdiction. It takes, however, preliminary cognizance of all matters
brought before the Assembly, and the Assembly cannot vote on any question unless it has first been
considered by the Council and placed on the programme by the Prytanes; since a person who carries a motion
in the Assembly is liable to an action for illegal proposal on these grounds.

The Council also superintends the triremes that are already in existence, with their tackle and sheds, and
builds new triremes or quadriremes, whichever the Assembly votes, with tackle and sheds to match. The
Assembly appoints master-builders for the ships by vote; and if they do not hand them over completed to the
next Council, the old Council cannot receive the customary donation-that being normally given to it during
its successor's term of office. For the building of the triremes it appoints ten commissioners, chosen from its

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THE ATHENIAN CONSTITUTION

own members. The Council also inspects all public buildings, and if it is of opinion that the state is being
defrauded, it reports the culprit to the Assembly, and on condemnation hands him over to the law-courts.

The Council also co-operates with other magistrates in most of their duties. First there are the treasurers of
Athena, ten in number, elected by lot, one from each tribe. According to the law of Solon-which is still in
force-they must be Pentacosiomedimni, but in point of fact the person on whom the lot falls holds the office
even though he be quite a poor man. These officers take over charge of the statue of Athena, the figures of
Victory, and all the other ornaments of the temple, together with the money, in the presence of the Council.
Then there are the Commissioners for Public Contracts (Poletae), ten in number, one chosen by lot from each
tribe, who farm out the public contracts. They lease the mines and taxes, in conjunction with the Military
Treasurer and the Commissioners of the Theoric fund, in the presence of the Council, and grant, to the
persons indicated by the vote of the Council, the mines which are let out by the state, including both the
workable ones, which are let for three years, and those which are let under special agreements years. They
also sell, in the presence of the Council, the property of those who have gone into exile from the court of the
Areopagus, and of others whose goods have been confiscated, and the nine Archons ratify the contracts. They
also hand over to the Council lists of the taxes which are farmed out for the year, entering on whitened tablets
the name of the lessee and the amount paid. They make separate lists, first of those who have to pay their
instalments in each prytany, on ten several tablets, next of those who pay thrice in the year, with a separate
tablet for each instalment, and finally of those who pay in the ninth prytany. They also draw up a list of farms
and dwellings which have been confiscated and sold by order of the courts; for these too come within their
province. In the case of dwellings the value must be paid up in five years, and in that of farms, in ten. The
instalments are paid in the ninth prytany. Further, the King-archon brings before the Council the leases of the
sacred enclosures, written on whitened tablets. These too are leased for ten years, and the instalments are paid
in the prytany; consequently it is in this prytany that the greatest amount of money is collected. The tablets
containing the lists of the instalments are carried into the Council, and the public clerk takes charge of them.
Whenever a payment of instalments is to be made he takes from the pigeon-holes the precise list of the sums
which are to be paid and struck off on that day, and delivers it to the Receivers-General. The rest are kept
apart, in order that no sum may be struck off before it is paid.

There are ten Receivers-General (Apodectae), elected by lot, one from each tribe. These officers receive the
tablets, and strike off the instalments as they are paid, in the presence of the Council in the Council-chamber,
and give the tablets back to the public clerk. If any one fails to pay his instalment, a note is made of it on the
tablet; and he is bound to pay double the amount of the deficiency, or, in default, to be imprisoned. The
Council has full power by the laws to exact these payments and to inflict this imprisonment. They receive all
the instalments, therefore, on one day, and portion the money out among the magistrates; and on the next day
they bring up the report of the apportionment, written on a wooden notice-board, and read it out in the
Council-chamber, after which they ask publicly in the Council whether any one knows of any malpractice in
reference to the apportionment, on the part of either a magistrate or a private individual, and if any one is
charged with malpractice they take a vote on it.

The Council also elects ten Auditors (Logistae) by lot from its own members, to audit the accounts of the
magistrates for each prytany. They also elect one Examiner of Accounts (Euthunus) by lot from each tribe,
with two assessors (Paredri) for each examiner, whose duty it is to sit at the ordinary market hours, each
opposite the statue of the eponymous hero of his tribe; and if any one wishes to prefer a charge, on either
public or private grounds, against any magistrate who has passed his audit before the law-courts, within three
days of his having so passed, he enters on a whitened tablet his own name and that of the magistrate

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THE ATHENIAN CONSTITUTION

prosecuted, together with the malpractice that is alleged against him. He also appends his claim for a penalty
of such amount as seems to him fitting, and gives in the record to the Examiner. The latter takes it, and if
after reading it he considers it proved he hands it over, if a private case, to the local justices who introduce
cases for the tribe concerned, while if it is a public case he enters it on the register of the Thesmothetae. Then,
if the Thesmothetae accept it, they bring the accounts of this magistrate once more before the law-court, and
the decision of the jury stands as the final judgement.

The Council also inspects the horses belonging to the state. If a man who has a good horse is found to keep it
in bad condition, he is mulcted in his allowance of corn; while those which cannot keep up or which shy and
will not stand steady, it brands with a wheel on the jaw, and the horse so marked is disqualified for service. It
also inspects those who appear to be fit for service as scouts, and any one whom it rejects is deprived of his
horse. It also examines the infantry who serve among the cavalry, and any one whom it rejects ceases to
receive his pay. The roll of the cavalry is drawn up by the Commissioners of Enrolment (Catalogeis), ten in
number, elected by the Assembly by open vote. They hand over to the Hipparchs and Phylarchs the list of
those whom they have enrolled, and these officers take it and bring it up before the Council, and there open
the sealed tablet containing the names of the cavalry. If any of those who have been on the roll previously
make affidavit that they are physically incapable of cavalry service, they strike them out; then they call up the
persons newly enrolled, and if any one makes affidavit that he is either physically or pecuniarily incapable of
cavalry service they dismiss him, but if no such affidavit is made the Council vote whether the individual in
question is suitable for the purpose or not. If they vote in the affirmative his name is entered on the tablet; if
not, he is dismissed with the others.

Formerly the Council used to decide on the plans for public buildings and the contract for making the robe of
Athena; but now this work is done by a jury in the law-courts appointed by lot, since the Council was
considered to have shown favouritism in its decisions. The Council also shares with the Military Treasurer
the superintendence of the manufacture of the images of Victory and the prizes at the Panathenaic festival.

The Council also examines infirm paupers; for there is a law which provides that persons possessing less than
three minas, who are so crippled as to be unable to do any work, are, after examination by the Council, to
receive two obols a day from the state for their support. A treasurer is appointed by lot to attend to them.

The Council also, speaking broadly, cooperates in most of the duties of all the other magistrates; and this
ends the list of the functions of that body.

There are ten Commissioners for Repairs of Temples, elected by lot, who receive a sum of thirty minas from
the Receivers-General, and therewith carry out the most necessary repairs in the temples.

There are also ten City Commissioners (Astynomi), of whom five hold office in Piraeus and five in the city.
Their duty is to see that female flute-and harp-and lute-players are not hired at more than two drachmas,
and if more than one person is anxious to hire the same girl, they cast lots and hire her out to the person to
whom the lot falls. They also provide that no collector of sewage shall shoot any of his sewage within ten
stradia of the walls; they prevent people from blocking up the streets by building, or stretching barriers across
them, or making drain-pipes in mid-air with a discharge into the street, or having doors which open
outwards; they also remove the corpses of those who die in the streets, for which purpose they have a body of
state slaves assigned to them.

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THE ATHENIAN CONSTITUTION

Market Commissioners (Agoranomi) are elected by lot, five for Piraeus, five for the city. Their statutory duty
is to see that all articles offered for sale in the market are pure and unadulterated.

Commissioners of Weights and Measures (Metronomi) are elected by lot, five for the city, and five for
Piraeus. They see that sellers use fair weights and measures.

Formerly there were ten Corn Commissioners (Sitophylaces), elected by lot, five for Piraeus, and five for the
city; but now there are twenty for the city and fifteen for Piraeus. Their duties are, first, to see that the
unprepared corn in the market is offered for sale at reasonable prices, and secondly, to see that the millers sell
barley meal at a price proportionate to that of barley, and that the bakers sell their loaves at a price
proportionate to that of wheat, and of such weight as the Commissioners may appoint; for the law requires
them to fix the standard weight.

There are ten Superintendents of the Mart, elected by lot, whose duty is to superintend the Mart, and to
compel merchants to bring up into the city two-thirds of the corn which is brought by sea to the Corn Mart.

The Eleven also are appointed by lot to take care of the prisoners in the state gaol. Thieves, kidnappers, and
pickpockets are brought to them, and if they plead guilty they are executed, but if they deny the charge the
Eleven bring the case before the law-courts; if the prisoners are acquitted, they release them, but if not, they
then execute them. They also bring up before the law-courts the list of farms and houses claimed as
state-property; and if it is decided that they are so, they deliver them to the Commissioners for Public
Contracts. The Eleven also bring up informations laid against magistrates alleged to be disqualified; this
function comes within their province, but some such cases are brought up by the Thesmothetae.

There are also five Introducers of Cases (Eisagogeis), elected by lot, one for each pair of tribes, who bring up
the 'monthly' cases to the law-courts. 'Monthly' cases are these: refusal to pay up a dowry where a party is
bound to do so, refusal to pay interest on money borrowed at 12 per cent., or where a man desirous of setting
up business in the market has borrowed from another man capital to start with; also cases of slander, cases
arising out of friendly loans or partnerships, and cases concerned with slaves, cattle, and the office of
trierarch, or with banks. These are brought up as 'monthly' cases and are introduced by these officers; but the
Receivers-General perform the same function in cases for or against the farmers of taxes. Those in which the
sum concerned is not more than ten drachmas they can decide summarily, but all above that amount they
bring into the law-courts as 'monthly' cases.

The Forty are also elected by lot, four from each tribe, before whom suitors bring all other cases. Formerly
they were thirty in number, and they went on circuit through the demes to hear causes; but after the oligarchy
of the Thirty they were increased to forty. They have full powers to decide cases in which the amount at issue
does not exceed ten drachmas, but anything beyond that value they hand over to the Arbitrators. The
Arbitrators take up the case, and, if they cannot bring the parties to an agreement, they give a decision. If
their decision satisfies both parties, and they abide by it, the case is at an end; but if either of the parties
appeals to the law-courts, the Arbitrators enclose the evidence, the pleadings, and the laws quoted in the case
in two urns, those of the plaintiff in the one, and those of the defendant in the other. These they seal up and,
having attached to them the decision of the arbitrator, written out on a tablet, place them in the custody of the
four justices whose function it is to introduce cases on behalf of the tribe of the defendant. These officers take

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THE ATHENIAN CONSTITUTION

them and bring up the case before the law-court, to a jury of two hundred and one members in cases up to the
value of a thousand drachmas, or to one of four hundred and one in cases above that value. No laws or
pleadings or evidence may be used except those which were adduced before the Arbitrator, and have been
enclosed in the urns.

The Arbitrators are persons in the sixtieth year of their age; this appears from the schedule of the Archons and
the Eponymi. There are two classes of Eponymi, the ten who give their names to the tribes, and the forty-two
of the years of service. The youths, on being enrolled among the citizens, were formerly registered upon
whitened tablets, and the names were appended of the Archon in whose year they were enrolled, and of the
Eponymus who had been in course in the preceding year; at the present day they are written on a bronze
pillar, which stands in front of the Council-chamber, near the Eponymi of the tribes. Then the Forty take the
last of the Eponymi of the years of service, and assign the arbitrations to the persons belonging to that year,
casting lots to determine which arbitrations each shall undertake; and every one is compelled to carry through
the arbitrations which the lot assigns to him. The law enacts that any one who does not serve as Arbitrator
when he has arrived at the necessary age shall lose his civil rights, unless he happens to be holding some
other office during that year, or to be out of the country. These are the only persons who escape the duty. Any
one who suffers injustice at the hands of the Arbitrator may appeal to the whole board of Arbitrators, and if
they find the magistrate guilty, the law enacts that he shall lose his civil rights. The persons thus condemned
have, however, in their turn an appeal. The Eponymi are also used in reference to military expeditions; when
the men of military age are despatched on service, a notice is put up stating that the men from such-and such
an Archon and Eponymus to such-and such another Archon and Eponymus are to go on the expedition.

The following magistrates also are elected by lot: Five Commissioners of Roads (Hodopoei), who, with an
assigned body of public slaves, are required to keep the roads in order: and ten Auditors, with ten assistants,
to whom all persons who have held any office must give in their accounts. These are the only officers who
audit the accounts of those who are subject to examination, and who bring them up for examination before
the law-courts. If they detect any magistrate in embezzlement, the jury condemn him for theft, and he is
obliged to repay tenfold the sum he is declared to have misappropriated. If they charge a magistrate with
accepting bribes and the jury convict him, they fine him for corruption, and this sum too is repaid tenfold. Or
if they convict him of unfair dealing, he is fined on that charge, and the sum assessed is paid without increase,
if payment is made before the ninth prytany, but otherwise it is doubled. A tenfold fine is not doubled.

The Clerk of the prytany, as he is called, is also elected by lot. He has the charge of all public documents, and
keeps the resolutions which are passed by the Assembly, and checks the transcripts of all other official papers
and attends at the sessions of the Council. Formerly he was elected by open vote, and the most distinguished
and trustworthy persons were elected to the post, as is known from the fact that the name of this officer is
appended on the pillars recording treaties of alliance and grants of consulship and citizenship. Now, however,
he is elected by lot. There is, in addition, a Clerk of the Laws, elected by lot, who attends at the sessions of
the Council; and he too checks the transcript of all the laws. The Assembly also elects by open vote a clerk to
read documents to it and to the Council; but he has no other duty except that of reading aloud.

The Assembly also elects by lot the Commissioners of Public Worship (Hieropoei) known as the
Commissioners for Sacrifices, who offer the sacrifices appointed by oracle, and, in conjunction with the
seers, take the auspices whenever there is occasion. It also elects by lot ten others, known as Annual
Commissioners, who offer certain sacrifices and administer all the quadrennial festivals except the
Panathenaea. There are the following quadrennial festivals: first that of Delos (where there is also a sexennial
festival), secondly the Brauronia, thirdly the Heracleia, fourthly the Eleusinia, and fifthly the Panathenaea;
and no two of these are celebrated in the same place. To these the Hephaestia has now been added, in the

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THE ATHENIAN CONSTITUTION

archonship of Cephisophon.

An Archon is also elected by lot for Salamis, and a Demarch for Piraeus. These officers celebrate the
Dionysia in these two places, and appoint Choregi. In Salamis, moreover, the name of the Archon is publicly
recorded.

All the foregoing magistrates are elected by lot, and their powers are those which have been stated. To pass
on to the nine Archons, as they are called, the manner of their appointment from the earliest times has been
described already. At the present day six Thesmothetae are elected by lot, together with their clerk, and in
addition to these an Archon, a King, and a Polemarch. One is elected from each tribe. They are examined first
of all by the Council of Five Hundred, with the exception of the clerk. The latter is examined only in the
lawcourt, like other magistrates (for all magistrates, whether elected by lot or by open vote, are examined
before entering on their offices); but the nine Archons are examined both in the Council and again in the
law-court. Formerly no one could hold the office if the Council rejected him, but now there is an appeal to
the law-court, which is the final authority in the matter of the examination. When they are examined, they
are asked, first, 'Who is your father, and of what deme? who is your father's father? who is your mother? who
is your mother's father, and of what deme?' Then the candidate is asked whether he possesses an ancestral
Apollo and a household Zeus, and where their sanctuaries are; next if he possesses a family tomb, and where;
then if he treats his parents well, and pays his taxes, and has served on the required military expeditions.
When the examiner has put these questions, he proceeds, 'Call the witnesses to these facts'; and when the
candidate has produced his witnesses, he next asks, 'Does any one wish to make any accusation against this
man?' If an accuser appears, he gives the parties an opportunity of making their accusation and defence, and
then puts it to the Council to pass the candidate or not, and to the law-court to give the final vote. If no one
wishes to make an accusation, he proceeds at once to the vote. Formerly a single individual gave the vote, but
now all the members are obliged to vote on the candidates, so that if any unprincipled candidate has managed
to get rid of his accusers, it may still be possible for him to be disqualified before the law-court. When the
examination has been thus completed, they proceed to the stone on which are the pieces of the victims, and
on which the Arbitrators take oath before declaring their decisions, and witnesses swear to their testimony.
On this stone the Archons stand, and swear to execute their office uprightly and according to the laws, and
not to receive presents in respect of the performance of their duties, or, if they do, to dedicate a golden statue.
When they have taken this oath they proceed to the Acropolis, and there they repeat it; after this they enter
upon their office.

The Archon, the King, and the Polemarch have each two assessors, nominated by themselves. These officers
are examined in the lawcourt before they begin to act, and give in accounts on each occasion of their acting.

As soon as the Archon enters office, he begins by issuing a proclamation that whatever any one possessed
before he entered into office, that he shall possess and hold until the end of his term. Next he assigns Choregi
to the tragic poets, choosing three of the richest persons out of the whole body of Athenians. Formerly he
used also to assign five Choregi to the comic poets, but now the tribes provide the Choregi for them. Then he
receives the Choregi who have been appointed by the tribes for the men's and boys' choruses and the comic
poets at the Dionysia, and for the men's and boys' choruses at the Thargelia (at the Dionysia there is a chorus
for each tribe, but at the Thargelia one between two tribes, each tribe bearing its share in providing it); he
transacts the exchanges of properties for them, and reports any excuses that are tendered, if any one says that
he has already borne this burden, or that he is exempt because he has borne a similar burden and the period of
his exemption has not yet expired, or that he is not of the required age; since the Choregus of a boys' chorus

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THE ATHENIAN CONSTITUTION

must be over forty years of age. He also appoints Choregi for the festival at Delos, and a chief of the mission
for the thirty-oar boat which conveys the youths thither. He also superintends sacred processions, both that in
honour of Asclepius, when the initiated keep house, and that of the great Dionysia-the latter in conjunction
with the Superintendents of that festival. These officers, ten in number, were formerly elected by open vote in
the Assembly, and used to provide for the expenses of the procession out of their private means; but now one
is elected by lot from each tribe, and the state contributes a hundred minas for the expenses. The Archon also
superintends the procession at the Thargelia, and that in honour of Zeus the Saviour. He also manages the
contests at the Dionysia and the Thargelia.

These, then, are the festivals which he superintends. The suits and indictments which come before him, and
which he, after a preliminary inquiry, brings up before the lawcourts, are as follows. Injury to parents (for
bringing these actions the prosecutor cannot suffer any penalty); injury to orphans (these actions lie against
their guardians); injury to a ward of state (these lie against their guardians or their husbands), injury to an
orphan's estate (these too lie against the guardians); mental derangement, where a party charges another with
destroying his own property through unsoundness of mind; for appointment of liquidators, where a party
refuses to divide property in which others have a share; for constituting a wardship; for determining between
rival claims to a wardship; for granting inspection of property to which another party lays claim; for
appointing oneself as guardian; and for determining disputes as to inheritances and wards of state. The
Archon also has the care of orphans and wards of state, and of women who, on the death of their husbands,
declare themselves to be with child; and he has power to inflict a fine on those who offend against the
persons under his charge, or to bring the case before the law-courts. He also leases the houses of orphans and
wards of state until they reach the age of fourteen, and takes mortgages on them; and if the guardians fail to
provide the necessary food for the children under their charge, he exacts it from them. Such are the duties of
the Archon.

The King in the first place superintends the mysteries, in conjunction with the Superintendents of Mysteries.
The latter are elected in the Assembly by open vote, two from the general body of Athenians, one from the
Eumolpidae, and one from the Ceryces. Next, he superintends the Lenaean Dionysia, which consists of a
procession and a contest. The procession is ordered by the King and the Superintendents in conjunction; but
the contest is managed by the King alone. He also manages all the contests of the torch-race; and to speak
broadly, he administers all the ancestral sacrifices. Indictments for impiety come before him, or any disputes
between parties concerning priestly rites; and he also determines all controversies concerning sacred rites for
the ancient families and the priests. All actions for homicide come before him, and it is he that makes the
proclamation requiring polluted persons to keep away from sacred ceremonies. Actions for homicide and
wounding are heard, if the homicide or wounding be willful, in the Areopagus; so also in cases of killing by
poison, and of arson. These are the only cases heard by that Council. Cases of unintentional homicide, or of
intent to kill, or of killing a slave or a resident alien or a foreigner, are heard by the court of Palladium. When
the homicide is acknowledged, but legal justification is pleaded, as when a man takes an adulterer in the act,
or kills another by mistake in battle, or in an athletic contest, the prisoner is tried in the court of Delphinium.
If a man who is in banishment for a homicide which admits of reconcilliation incurs a further charge of
killing or wounding, he is tried in Phreatto, and he makes his defence from a boat moored near the shore. All
these cases, except those which are heard in the Areopagus, are tried by the Ephetae on whom the lot falls.
The King introduces them, and the hearing is held within sacred precincts and in the open air. Whenever the
King hears a case he takes off his crown. The person who is charged with homicide is at all other times
excluded from the temples, nor is it even lawful for him to enter the market-place; but on the occasion of his
trial he enters the temple and makes his defence. If the actual offender is unknown, the writ runs against 'the
doer of the deed'. The King and the tribe-kings also hear the cases in which the guilt rests on inanimate
objects and the lower animal.

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THE ATHENIAN CONSTITUTION

The Polemarch performs the sacrifices to Artemis the huntress and to Enyalius, and arranges the contest at
the funeral of those who have fallen in war, and makes offerings to the memory of Harmodius and
Aristogeiton. Only private actions come before him, namely those in which resident aliens, both ordinary and
privileged, and agents of foreign states are concerned. It is his duty to receive these cases and divide them
into ten groups, and assign to each tribe the group which comes to it by lot; after which the magistrates who
introduce cases for the tribe hand them over to the Arbitrators. The Polemarch, however, brings up in person
cases in which an alien is charged with deserting his patron or neglecting to provide himself with one, and
also of inheritances and wards of state where aliens are concerned; and in fact, generally, whatever the
Archon does for citizens, the Polemarch does for aliens.

The Thesmothetae in the first place have the power of prescribing on what days the lawcourts are to sit, and
next of assigning them to the several magistrates; for the latter must follow the arrangement which the
Thesmothetae assign. Moreover they introduce impeachments before the Assembly, and bring up all votes for
removal from office, challenges of a magistrate's conduct before the Assembly, indictments for illegal
proposals, or for proposing a law which is contrary to the interests of the state, complaints against Proedri or
their president for their conduct in office, and the accounts presented by the generals. All indictments also
come before them in which a deposit has to be made by the prosecutor, namely, indictments for concealment
of foreign origin, for corrupt evasion of foreign origin (when a man escapes the disqualification by bribery),
for blackmailing accusations, bribery, false entry of another as a state debtor, false testimony to the service of
a summons, conspiracy to enter a man as a state debtor, corrupt removal from the list of debtors, and adultery.
They also bring up the examinations of all magistrates, and the rejections by the demes and the
condemnations by the Council. Moreover they bring up certain private suits in cases of merchandise and
mines, or where a slave has slandered a free man. It is they also who cast lots to assign the courts to the
various magistrates, whether for private or public cases. They ratify commercial treaties, and bring up the
cases which arise out of such treaties; and they also bring up cases of perjury from the Areopagus. The
casting of lots for the jurors is conducted by all the nine Archons, with the clerk to the Thesmothetae as the
tenth, each performing the duty for his own tribe. Such are the duties of the nine Archons.

There are also ten Commissioners of Games (Athlothetae), elected by lot, one from each tribe. These officers,
after passing an examination, serve for four years; and they manage the Panathenaic procession, the contest in
music and that in gymnastic, and the horse-race; they also provide the robe of Athena and, in conjunction
with the Council, the vases, and they present the oil to the athletes. This oil is collected from the sacred
olives. The Archon requisitions it from the owners of the farms on which the sacred olives grow, at the rate of
three-quarters of a pint from each plant. Formerly the state used to sell the fruit itself, and if any one dug up
or broke down one of the sacred olives, he was tried by the Council of Areopagus, and if he was condemned,
the penalty was death. Since, however, the oil has been paid by the owner of the farm, the procedure has
lapsed, though the law remains; and the oil is a state charge upon the property instead of being taken from the
individual plants. When, then, the Archon has collected the oil for his year of office, he hands it over to the
Treasurers to preserve in the Acropolis, and he may not take his seat in the Areopagus until he has paid over
to the Treasurers the full amount. The Treasurers keep it in the Acropolis until the Panathenaea, when they
measure it out to the Commissioners of Games, and they again to the victorious competitors. The prizes for
the victors in the musical contest consist of silver and gold, for the victors in manly vigour, of shields, and for
the victors in the gymnastic contest and the horse-race, of oil.

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THE ATHENIAN CONSTITUTION

All officers connected with military service are elected by open vote. In the first place, ten Generals
(Strategi), who were formerly elected one from each tribe, but now are chosen from the whole mass of
citizens. Their duties are assigned to them by open vote; one is appointed to command the heavy infantry, and
leads them if they go out to war; one to the defence of the country, who remains on the defensive, and fights
if there is war within the borders of the country; two to Piraeus, one of whom is assigned to Munichia, and
one to the south shore, and these have charge of the defence of the Piraeus; and one to superintend the
symmories, who nominates the trierarchs arranges exchanges of properties for them, and brings up actions to
decide on rival claims in connexion with them. The rest are dispatched to whatever business may be on hand
at the moment. The appointment of these officers is submitted for confirmation in each prytany, when the
question is put whether they are considered to be doing their duty. If any officer is rejected on this vote, he is
tried in the lawcourt, and if he is found guilty the people decide what punishment or fine shall be inflicted on
him; but if he is acquitted he resumes his office. The Generals have full power, when on active service, to
arrest any one for insubordination, or to cashier him publicly, or to inflict a fine; the latter is, however,
unusual.

There are also ten Taxiarchs, one from each tribe, elected by open vote; and each commands his own
tribesmen and appoints captains of companies (Lochagi). There are also two Hipparchs, elected by open vote
from the whole mass of the citizens, who command the cavalry, each taking five tribes. They have the same
powers as the Generals have in respect of the infantry, and their appointments are also subject to
confirmation. There are also ten Phylarchs, elected by open vote, one from each tribe, to command the
cavalry, as the Taxiarchs do the infantry. There is also a Hipparch for Lemnos, elected by open vote, who has
charge of the cavalry in Lemnos. There is also a treasurer of the Paralus, and another of the Ammonias,
similarly elected.

Of the magistrates elected by lot, in former times some including the nine Archons, were elected out of the
tribe as a whole, while others, namely those who are now elected in the Theseum, were apportioned among
the demes; but since the demes used to sell the elections, these magistrates too are now elected from the
whole tribe, except the members of the Council and the guards of the dockyards, who are still left to the
demes.

Pay is received for the following services. First the members of the Assembly receive a drachma for the
ordinary meetings, and nine obols for the 'sovereign' meeting. Then the jurors at the law-courts receive three
obols; and the members of the Council five obols. They Prytanes receive an allowance of an obol for their
maintenance. The nine Archons receive four obols apiece for maintenance, and also keep a herald and a
flute-player; and the Archon for Salamis receives a drachma a day. The Commissioners for Games dine in
the Prytaneum during the month of Hecatombaeon in which the Panathenaic festival takes place, from the
fourteenth day onwards. The Amphictyonic deputies to Delos receive a drachma a day from the exchequer of
Delos. Also all magistrates sent to Samos, Scyros, Lemnos, or Imbros receive an allowance for their
maintenance. The military offices may be held any number of times, but none of the others more than once,
except the membership of the Council, which may be held twice.

The juries for the law-courts are chosen by lot by the nine Archons, each for their own tribe, and by the clerk
to the Thesmothetae for the tenth. There are ten entrances into the courts, one for each tribe; twenty rooms in
which the lots are drawn, two for each tribe; a hundred chests, ten for each tribe; other chests, in which are

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THE ATHENIAN CONSTITUTION

placed the tickets of the jurors on whom the lot falls; and two vases. Further, staves, equal in number to the
jurors required, are placed by the side of each entrance; and counters are put into one vase, equal in number
to the staves. These are inscribed with letters of the alphabet beginning with the eleventh (lambda), equal in
number to the courts which require to be filled. All persons above thirty years of age are qualified to serve as
jurors, provided they are not debtors to the state and have not lost their civil rights. If any unqualified person
serves as juror, an information is laid against him, and he is brought before the court; and, if he is convicted,
the jurors assess the punishment or fine which they consider him to deserve. If he is condemned to a money
fine, he must be imprisoned until he has paid up both the original debt, on account of which the information
was laid against him, and also the fine which the court as imposed upon him. Each juror has his ticket of
boxwood, on which is inscribed his name, with the name of his father and his deme, and one of the letters of
the alphabet up to kappa; for the jurors in their several tribes are divided into ten sections, with approximately
an equal number in each letter. When the Thesmothetes has decided by lot which letters are required to attend
at the courts, the servant puts up above each court the letter which has been assigned to it by the lot.

The ten chests above mentioned are placed in front of the entrance used by each tribe, and are inscribed with
the letters of the alphabet from alpha to kappa. The jurors cast in their tickets, each into the chest on which is
inscribed the letter which is on his ticket; then the servant shakes them all up, and the Archon draws one
ticket from each chest. The individual so selected is called the Ticket-hanger (Empectes), and his function is
to hang up the tickets out of his chest on the bar which bears the same letter as that on the chest. He is chosen
by lot, lest, if the Ticket-hanger were always the same person, he might tamper with the results. There are
five of these bars in each of the rooms assigned for the lot-drawing. Then the Archon casts in the dice and
thereby chooses the jurors from each tribe, room by room. The dice are made of brass, coloured black or
white; and according to the number of jurors required, so many white dice are put in, one for each five
tickets, while the remainder are black, in the same proportion. As the Archon draws out the dice, the crier
calls out the names of the individuals chosen. The Ticket-hanger is included among those selected. Each
juror, as he is chosen and answers to his name, draws a counter from the vase, and holding it out with the
letter uppermost shows it first to the presiding Archon; and he, when he has seen it, throws the ticket of the
juror into the chest on which is inscribed the letter which is on the counter, so that the juror must go into the
court assigned to him by lot, and not into one chosen by himself, and that it may be impossible for any one to
collect the jurors of his choice into any particular court. For this purpose chests are placed near the Archon, as
many in number as there are courts to be filled that day, bearing the letters of the courts on which the lot has
fallen.

The juror thereupon, after showing his counter again to the attendant, passes through the barrier into the
court. The attendant gives him a staff of the same colour as the court bearing the letter which is on his
counter, so as to ensure his going into the court assigned to him by lot; since, if he were to go into any other,
he would be betrayed by the colour of his staff. Each court has a certain colour painted on the lintel of the
entrance. Accordingly the juror, bearing his staff, enters the court which has the same colour as his staff, and
the same letter as his counter. As he enters, he receives a voucher from the official to whom this duty has
been assigned by lot. So with their counters and their staves the selected jurors take their seats in the court,
having thus completed the process of admission. The unsuccessful candidates receive back their tickets from
the Ticket-hangers. The public servants carry the chests from each tribe, one to each court, containing the
names of the members of the tribe who are in that court, and hand them over to the officials assigned to the
duty of giving back their tickets to the jurors in each court, so that these officials may call them up by name
and pay them their fee.

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When all the courts are full, two ballot boxes are placed in the first court, and a number of brazen dice,
bearing the colours of the several courts, and other dice inscribed with the names of the presiding magistrates.
Then two of the Thesmothetae, selected by lot, severally throw the dice with the colours into one box, and
those with the magistrates' names into the other. The magistrate whose name is first drawn is thereupon
proclaimed by the crier as assigned for duty in the court which is first drawn, and the second in the second,
and similarly with the rest. The object of this procedure is that no one may know which court he will have,
but that each may take the court assigned to him by lot.

When the jurors have come in, and have been assigned to their respective courts, the presiding magistrate in
each court draws one ticket out of each chest (making ten in all, one out of each tribe), and throws them into
another empty chest. He then draws out five of them, and assigns one to the superintendence of the
water-clock, and the other four to the telling of the votes. This is to prevent any tampering beforehand with
either the superintendent of the clock or the tellers of the votes, and to secure that there is no malpractice in
these respects. The five who have not been selected for these duties receive from them a statement of the
order in which the jurors shall receive their fees, and of the places where the several tribes shall respectively
gather in the court for this purpose when their duties are completed; the object being that the jurors may be
broken up into small groups for the reception of their pay, and not all crowd together and impede one another.

These preliminaries being concluded, the cases are called on. If it is a day for private cases, the private
litigants are called. Four cases are taken in each of the categories defined in the law, and the litigants swear to
confine their speeches to the point at issue. If it is a day for public causes, the public litigants are called, and
only one case is tried. Water-clocks are provided, having small supply-tubes, into which the water is poured
by which the length of the pleadings is regulated. Ten gallons are allowed for a case in which an amount of
more than five thousand drachmas is involved, and three for the second speech on each side. When the
amount is between one and five thousand drachmas, seven gallons are allowed for the first speech and two for
the second; when it is less than one thousand, five and two. Six gallons are allowed for arbitrations between
rival claimants, in which there is no second speech. The official chosen by lot to superintend the water-clock
places his hand on the supply tube whenever the clerk is about to read a resolution or law or affidavit or
treaty. When, however, a case is conducted according to a set measurement of the day, he does not stop the
supply, but each party receives an equal allowance of water. The standard of measurement is the length of the
days in the month Poseideon.... The measured day is employed in cases when imprisonment, death, exile, loss
of civil rights, or confiscation of goods is assigned as the penalty.

Most of the courts consist of 500 members...; and when it is necessary to bring public cases before a jury of
1,000 members, two courts combine for the purpose, the most important cases of all are brought 1,500 jurors,
or three courts. The ballot balls are made of brass with stems running through the centre, half of them having
the stem pierced and the other half solid. When the speeches are concluded, the officials assigned to the
taking of the votes give each juror two ballot balls, one pierced and one solid. This is done in full view of the
rival litigants, to secure that no one shall receive two pierced or two solid balls. Then the official designated
for the purpose takes away the jurors staves, in return for which each one as he records his vote receives a
brass voucher market with the numeral 3 (because he gets three obols when he gives it up). This is to ensure
that all shall vote; since no one can get a voucher unless he votes. Two urns, one of brass and the other of
wood, stand in the court, in distinct spots so that no one may surreptitiously insert ballot balls; in these the
jurors record their votes. The brazen urn is for effective votes, the wooden for unused votes; and the brazen

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THE ATHENIAN CONSTITUTION

urn has a lid pierced so as to take only one ballot ball, in order that no one may put in two at a time.

When the jurors are about to vote, the crier demands first whether the litigants enter a protest against any of
the evidence; for no protest can be received after the voting has begun. Then he proclaims again, 'The pierced
ballot for the plaintiff, the solid for the defendant'; and the juror, taking his two ballot balls from the stand,
with his hand closed over the stem so as not to show either the pierced or the solid ballot to the litigants, casts
the one which is to count into the brazen urn, and the other into the wooden urn.

When all the jurors have voted, the attendants take the urn containing the effective votes and discharge them
on to a reckoning board having as many cavities as there are ballot balls, so that the effective votes, whether
pierced or solid, may be plainly displayed and easily counted. Then the officials assigned to the taking of the
votes tell them off on the board, the solid in one place and the pierced in another, and the crier announces the
numbers of the votes, the pierced ballots being for the prosecutor and the solid for the defendant. Whichever
has the majority is victorious; but if the votes are equal the verdict is for the defendant. Each juror receives
two ballots, and uses one to record his vote, and throws the other away.

Then, if damages have to be awarded, they vote again in the same way, first returning their pay-vouchers and
receiving back their staves. Half a gallon of water is allowed to each party for the discussion of the damages.
Finally, when all has been completed in accordance with the law, the jurors receive their pay in the order
assigned by the lot.

THE END

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Aristotle

The Categories

Table of Contents

The Categories 1

Aristotle 1

Section 1. 1

Part 1. 1

Part 2. 2

Part 3. 2

Part 4 2

Part 5. 3

Part 6. 6

Section 2. 8

Part 7. 8

Part 8. 11

Section 3. 15

Part 9. 15

Part 10. 15

Part 1 1. 18

Part 12. 18

Part 13. 19

Part 14 20

Part 15. 20

The Categories

Aristotle

Translated by E. M. Edghill

• Section 1

• Part 1

• Part 2

• Part 3

• Part 4

• Part 5

• Part 6

• Section 2

• Part 7

• Part 8

• Section 3

• Part 9

• Part 10

• Part 1 1

• Part 12

• Part 13

• Part 14

• Part 15

Section 1

Parti

Things are said to be named 'equivocally' when, though they have a common name, the definition
corresponding with the name differs for each. Thus, a real man and a figure in a picture can both lay claim to
the name 'animal'; yet these are equivocally so named, for, though they have a common name, the definition
corresponding with the name differs for each. For should any one define in what sense each is an animal, his
definition in the one case will be appropriate to that case only.

On the other hand, things are said to be named 'univocally' which have both the name and the definition
answering to the name in common. A man and an ox are both 'animal', and these are univocally so named,
inasmuch as not only the name, but also the definition, is the same in both cases: for if a man should state in
what sense each is an animal, the statement in the one case would be identical with that in the other.

Things are said to be named 'derivatively', which derive their name from some other name, but differ from it
in termination. Thus the grammarian derives his name from the word 'grammar', and the courageous man
from the word 'courage'.

The Categories 1

The Categories

Part 2

Forms of speech are either simple or composite. Examples of the latter are such expressions as 'the man runs',
'the man wins'; of the former 'man', 'ox', 'runs', 'wins'.

Of things themselves some are predicable of a subject, and are never present in a subject. Thus 'man' is
predicable of the individual man, and is never present in a subject.

By being 'present in a subject' I do not mean present as parts are present in a whole, but being incapable of
existence apart from the said subject.

Some things, again, are present in a subject, but are never predicable of a subject. For instance, a certain point
of grammatical knowledge is present in the mind, but is not predicable of any subject; or again, a certain
whiteness may be present in the body (for colour requires a material basis), yet it is never predicable of
anything.

Other things, again, are both predicable of a subject and present in a subject. Thus while knowledge is present
in the human mind, it is predicable of grammar.

There is, lastly, a class of things which are neither present in a subject nor predicable of a subject, such as the
individual man or the individual horse. But, to speak more generally, that which is individual and has the
character of a unit is never predicable of a subject. Yet in some cases there is nothing to prevent such being
present in a subject. Thus a certain point of grammatical knowledge is present in a subject.

Part 3

When one thing is predicated of another, all that which is predicable of the predicate will be predicable also
of the subject. Thus, 'man' is predicated of the individual man; but 'animal' is predicated of 'man'; it will,
therefore, be predicable of the individual man also: for the individual man is both 'man' and 'animal'.

If genera are different and co-ordinate, their differentiae are themselves different in kind. Take as an instance
the genus 'animal' and the genus 'knowledge'. 'With feet', 'two-footed', 'winged', 'aquatic', are differentiae of
'animal'; the species of knowledge are not distinguished by the same differentiae. One species of knowledge
does not differ from another in being 'two-footed'.

But where one genus is subordinate to another, there is nothing to prevent their having the same differentiae:
for the greater class is predicated of the lesser, so that all the differentiae of the predicate will be differentiae
also of the subject.

Part 4

Expressions which are in no way composite signify substance, quantity, quality, relation, place, time,
position, state, action, or affection. To sketch my meaning roughly, examples of substance are 'man' or 'the
horse', of quantity, such terms as 'two cubits long' or 'three cubits long', of quality, such attributes as 'white',
'grammatical'. 'Double', 'half, 'greater', fall under the category of relation; 'in a the market place', 'in the
Lyceum', under that of place; 'yesterday', 'last year', under that of time. 'Lying', 'sitting', are terms indicating
position, 'shod', 'armed', state; 'to lance', 'to cauterize', action; 'to be lanced', 'to be cauterized', affection.

No one of these terms, in and by itself, involves an affirmation; it is by the combination of such terms that
positive or negative statements arise. For every assertion must, as is admitted, be either true or false, whereas

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expressions which are not in any way composite such as 'man', 'white', 'runs', 'wins', cannot be either true or
false.

Part5

Substance, in the truest and primary and most definite sense of the word, is that which is neither predicable of
a subject nor present in a subject; for instance, the individual man or horse. But in a secondary sense those
things are called substances within which, as species, the primary substances are included; also those which,
as genera, include the species. For instance, the individual man is included in the species 'man', and the genus
to which the species belongs is 'animal'; these, therefore-that is to say, the species 'man' and the genus
'animal,-are termed secondary substances.

It is plain from what has been said that both the name and the definition of the predicate must be predicable
of the subject. For instance, 'man' is predicted of the individual man. Now in this case the name of the species
man' is applied to the individual, for we use the term 'man' in describing the individual; and the definition of
'man' will also be predicated of the individual man, for the individual man is both man and animal. Thus, both
the name and the definition of the species are predicable of the individual.

With regard, on the other hand, to those things which are present in a subject, it is generally the case that
neither their name nor their definition is predicable of that in which they are present. Though, however, the
definition is never predicable, there is nothing in certain cases to prevent the name being used. For instance,
'white' being present in a body is predicated of that in which it is present, for a body is called white: the
definition, however, of the colour white' is never predicable of the body.

Everything except primary substances is either predicable of a primary substance or present in a primary
substance. This becomes evident by reference to particular instances which occur. 'Animal' is predicated of
the species 'man', therefore of the individual man, for if there were no individual man of whom it could be
predicated, it could not be predicated of the species 'man' at all. Again, colour is present in body, therefore in
individual bodies, for if there were no individual body in which it was present, it could not be present in body
at all. Thus everything except primary substances is either predicated of primary substances, or is present in
them, and if these last did not exist, it would be impossible for anything else to exist.

Of secondary substances, the species is more truly substance than the genus, being more nearly related to
primary substance. For if any one should render an account of what a primary substance is, he would render a
more instructive account, and one more proper to the subject, by stating the species than by stating the genus.
Thus, he would give a more instructive account of an individual man by stating that he was man than by
stating that he was animal, for the former description is peculiar to the individual in a greater degree, while
the latter is too general. Again, the man who gives an account of the nature of an individual tree will give a
more instructive account by mentioning the species 'tree' than by mentioning the genus 'plant'.

Moreover, primary substances are most properly called substances in virtue of the fact that they are the
entities which underlie every, else, and that everything else is either predicated of them or present in them.
Now the same relation which subsists between primary substance and everything else subsists also between
the species and the genus: for the species is to the genus as subject is to predicate, since the genus is
predicated of the species, whereas the species cannot be predicated of the genus. Thus we have a second
ground for asserting that the species is more truly substance than the genus.

Of species themselves, except in the case of such as are genera, no one is more truly substance than another.
We should not give a more appropriate account of the individual man by stating the species to which he
belonged, than we should of an individual horse by adopting the same method of definition. In the same way,

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of primary substances, no one is more truly substance than another; an individual man is not more truly
substance than an individual ox.

It is, then, with good reason that of all that remains, when we exclude primary substances, we concede to
species and genera alone the name 'secondary substance', for these alone of all the predicates convey a
knowledge of primary substance. For it is by stating the species or the genus that we appropriately define any
individual man; and we shall make our definition more exact by stating the former than by stating the latter.
All other things that we state, such as that he is white, that he runs, and so on, are irrelevant to the definition.
Thus it is just that these alone, apart from primary substances, should be called substances.

Further, primary substances are most properly so called, because they underlie and are the subjects of
everything else. Now the same relation that subsists between primary substance and everything else subsists
also between the species and the genus to which the primary substance belongs, on the one hand, and every
attribute which is not included within these, on the other. For these are the subjects of all such. If we call an
individual man 'skilled in grammar', the predicate is applicable also to the species and to the genus to which
he belongs. This law holds good in all cases.

It is a common characteristic of all sub. stance that it is never present in a subject. For primary substance is
neither present in a subject nor predicated of a subject; while, with regard to secondary substances, it is clear
from the following arguments (apart from others) that they are not present in a subject. For 'man' is predicated
of the individual man, but is not present in any subject: for manhood is not present in the individual man. In
the same way, 'animal' is also predicated of the individual man, but is not present in him. Again, when a thing
is present in a subject, though the name may quite well be applied to that in which it is present, the definition
cannot be applied. Yet of secondary substances, not only the name, but also the definition, applies to the
subject: we should use both the definition of the species and that of the genus with reference to the individual
man. Thus substance cannot be present in a subject.

Yet this is not peculiar to substance, for it is also the case that differentiae cannot be present in subjects. The
characteristics 'terrestrial' and 'two-footed' are predicated of the species 'man', but not present in it. For they
are not in man. Moreover, the definition of the differentia may be predicated of that of which the differentia
itself is predicated. For instance, if the characteristic 'terrestrial' is predicated of the species 'man', the
definition also of that characteristic may be used to form the predicate of the species 'man': for 'man' is
terrestrial.

The fact that the parts of substances appear to be present in the whole, as in a subject, should not make us
apprehensive lest we should have to admit that such parts are not substances: for in explaining the phrase
'being present in a subject', we stated' that we meant 'otherwise than as parts in a whole'.

It is the mark of substances and of differentiae that, in all propositions of which they form the predicate, they
are predicated univocally. For all such propositions have for their subject either the individual or the species.
It is true that, inasmuch as primary substance is not predicable of anything, it can never form the predicate of
any proposition. But of secondary substances, the species is predicated of the individual, the genus both of
the species and of the individual. Similarly the differentiae are predicated of the species and of the
individuals. Moreover, the definition of the species and that of the genus are applicable to the primary
substance, and that of the genus to the species. For all that is predicated of the predicate will be predicated
also of the subject. Similarly, the definition of the differentiae will be applicable to the species and to the
individuals. But it was stated above that the word 'univocal' was applied to those things which had both name
and definition in common. It is, therefore, established that in every proposition, of which either substance or a
differentia forms the predicate, these are predicated univocally.

Part 5

The Categories

All substance appears to signify that which is individual. In the case of primary substance this is indisputably
true, for the thing is a unit. In the case of secondary substances, when we speak, for instance, of 'man' or
'animal', our form of speech gives the impression that we are here also indicating that which is individual, but
the impression is not strictly true; for a secondary substance is not an individual, but a class with a certain
qualification; for it is not one and single as a primary substance is; the words 'man', 'animal', are predicable of
more than one subject.

Yet species and genus do not merely indicate quality, like the term 'white'; 'white' indicates quality and
nothing further, but species and genus determine the quality with reference to a substance: they signify
substance qualitatively differentiated. The determinate qualification covers a larger field in the case of the
genus that in that of the species: he who uses the word 'animal' is herein using a word of wider extension than
he who uses the word 'man'.

Another mark of substance is that it has no contrary. What could be the contrary of any primary substance,
such as the individual man or animal? It has none. Nor can the species or the genus have a contrary. Yet this
characteristic is not peculiar to substance, but is true of many other things, such as quantity. There is nothing
that forms the contrary of 'two cubits long' or of 'three cubits long', or of 'ten', or of any such term. A man
may contend that 'much' is the contrary of 'little', or 'great' of 'small', but of definite quantitative terms no
contrary exists.

Substance, again, does not appear to admit of variation of degree. I do not mean by this that one substance
cannot be more or less truly substance than another, for it has already been stated' that this is the case; but that
no single substance admits of varying degrees within itself. For instance, one particular substance, 'man',
cannot be more or less man either than himself at some other time or than some other man. One man cannot
be more man than another, as that which is white may be more or less white than some other white object, or
as that which is beautiful may be more or less beautiful than some other beautiful object. The same quality,
moreover, is said to subsist in a thing in varying degrees at different times. A body, being white, is said to be
whiter at one time than it was before, or, being warm, is said to be warmer or less warm than at some other
time. But substance is not said to be more or less that which it is: a man is not more truly a man at one time
than he was before, nor is anything, if it is substance, more or less what it is. Substance, then, does not admit
of variation of degree.

The most distinctive mark of substance appears to be that, while remaining numerically one and the same, it
is capable of admitting contrary qualities. From among things other than substance, we should find ourselves
unable to bring forward any which possessed this mark. Thus, one and the same colour cannot be white and
black. Nor can the same one action be good and bad: this law holds good with everything that is not
substance. But one and the selfsame substance, while retaining its identity, is yet capable of admitting
contrary qualities. The same individual person is at one time white, at another black, at one time warm, at
another cold, at one time good, at another bad. This capacity is found nowhere else, though it might be
maintained that a statement or opinion was an exception to the rule. The same statement, it is agreed, can be
both true and false. For if the statement 'he is sitting' is true, yet, when the person in question has risen, the
same statement will be false. The same applies to opinions. For if any one thinks truly that a person is sitting,
yet, when that person has risen, this same opinion, if still held, will be false. Yet although this exception may
be allowed, there is, nevertheless, a difference in the manner in which the thing takes place. It is by
themselves changing that substances admit contrary qualities. It is thus that that which was hot becomes cold,
for it has entered into a different state. Similarly that which was white becomes black, and that which was bad
good, by a process of change; and in the same way in all other cases it is by changing that substances are
capable of admitting contrary qualities. But statements and opinions themselves remain unaltered in all
respects: it is by the alteration in the facts of the case that the contrary quality comes to be theirs. The
statement 'he is sitting' remains unaltered, but it is at one time true, at another false, according to
circumstances. What has been said of statements applies also to opinions. Thus, in respect of the manner in

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The Categories

which the thing takes place, it is the peculiar mark of substance that it should be capable of admitting
contrary qualities; for it is by itself changing that it does so.

If, then, a man should make this exception and contend that statements and opinions are capable of admitting
contrary qualities, his contention is unsound. For statements and opinions are said to have this capacity, not
because they themselves undergo modification, but because this modification occurs in the case of something
else. The truth or falsity of a statement depends on facts, and not on any power on the part of the statement
itself of admitting contrary qualities. In short, there is nothing which can alter the nature of statements and
opinions. As, then, no change takes place in themselves, these cannot be said to be capable of admitting
contrary qualities.

But it is by reason of the modification which takes place within the substance itself that a substance is said to
be capable of admitting contrary qualities; for a substance admits within itself either disease or health,
whiteness or blackness. It is in this sense that it is said to be capable of admitting contrary qualities.

To sum up, it is a distinctive mark of substance, that, while remaining numerically one and the same, it is
capable of admitting contrary qualities, the modification taking place through a change in the substance itself.

Let these remarks suffice on the subject of substance.

Part 6

Quantity is either discrete or continuous. Moreover, some quantities are such that each part of the whole has a
relative position to the other parts: others have within them no such relation of part to part.

Instances of discrete quantities are number and speech; of continuous, lines, surfaces, solids, and, besides
these, time and place.

In the case of the parts of a number, there is no common boundary at which they join. For example: two fives
make ten, but the two fives have no common boundary, but are separate; the parts three and seven also do not
join at any boundary. Nor, to generalize, would it ever be possible in the case of number that there should be
a common boundary among the parts; they are always separate. Number, therefore, is a discrete quantity.

The same is true of speech. That speech is a quantity is evident: for it is measured in long and short syllables.
I mean here that speech which is vocal. Moreover, it is a discrete quantity for its parts have no common
boundary. There is no common boundary at which the syllables join, but each is separate and distinct from
the rest.

A line, on the other hand, is a continuous quantity, for it is possible to find a common boundary at which its
parts join. In the case of the line, this common boundary is the point; in the case of the plane, it is the line: for
the parts of the plane have also a common boundary. Similarly you can find a common boundary in the case
of the parts of a solid, namely either a line or a plane.

Space and time also belong to this class of quantities. Time, past, present, and future, forms a continuous
whole. Space, likewise, is a continuous quantity; for the parts of a solid occupy a certain space, and these
have a common boundary; it follows that the parts of space also, which are occupied by the parts of the solid,
have the same common boundary as the parts of the solid. Thus, not only time, but space also, is a continuous
quantity, for its parts have a common boundary.

Quantities consist either of parts which bear a relative position each to each, or of parts which do not. The
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The Categories

parts of a line bear a relative position to each other, for each lies somewhere, and it would be possible to
distinguish each, and to state the position of each on the plane and to explain to what sort of part among the
rest each was contiguous. Similarly the parts of a plane have position, for it could similarly be stated what
was the position of each and what sort of parts were contiguous. The same is true with regard to the solid and
to space. But it would be impossible to show that the arts of a number had a relative position each to each, or
a particular position, or to state what parts were contiguous. Nor could this be done in the case of time, for
none of the parts of time has an abiding existence, and that which does not abide can hardly have position. It
would be better to say that such parts had a relative order, in virtue of one being prior to another. Similarly
with number: in counting, 'one' is prior to 'two', and 'two' to 'three', and thus the parts of number may be said
to possess a relative order, though it would be impossible to discover any distinct position for each. This
holds good also in the case of speech. None of its parts has an abiding existence: when once a syllable is
pronounced, it is not possible to retain it, so that, naturally, as the parts do not abide, they cannot have
position. Thus, some quantities consist of parts which have position, and some of those which have not.

Strictly speaking, only the things which I have mentioned belong to the category of quantity: everything else
that is called quantitative is a quantity in a secondary sense. It is because we have in mind some one of these
quantities, properly so called, that we apply quantitative terms to other things. We speak of what is white as
large, because the surface over which the white extends is large; we speak of an action or a process as
lengthy, because the time covered is long; these things cannot in their own right claim the quantitative
epithet. For instance, should any one explain how long an action was, his statement would be made in terms
of the time taken, to the effect that it lasted a year, or something of that sort. In the same way, he would
explain the size of a white object in terms of surface, for he would state the area which it covered. Thus the
things already mentioned, and these alone, are in their intrinsic nature quantities; nothing else can claim the
name in its own right, but, if at all, only in a secondary sense.

Quantities have no contraries. In the case of definite quantities this is obvious; thus, there is nothing that is
the contrary of 'two cubits long' or of 'three cubits long', or of a surface, or of any such quantities. A man
might, indeed, argue that 'much' was the contrary of 'little', and 'great' of 'small'. But these are not
quantitative, but relative; things are not great or small absolutely, they are so called rather as the result of an
act of comparison. For instance, a mountain is called small, a grain large, in virtue of the fact that the latter is
greater than others of its kind, the former less. Thus there is a reference here to an external standard, for if the
terms 'great' and 'small' were used absolutely, a mountain would never be called small or a grain large. Again,
we say that there are many people in a village, and few in Athens, although those in the city are many times
as numerous as those in the village: or we say that a house has many in it, and a theatre few, though those in
the theatre far outnumber those in the house. The terms 'two cubits long, "three cubits long,' and so on
indicate quantity, the terms 'great' and 'small' indicate relation, for they have reference to an external standard.
It is, therefore, plain that these are to be classed as relative.

Again, whether we define them as quantitative or not, they have no contraries: for how can there be a
contrary of an attribute which is not to be apprehended in or by itself, but only by reference to something
external? Again, if 'great' and 'small' are contraries, it will come about that the same subject can admit
contrary qualities at one and the same time, and that things will themselves be contrary to themselves. For it
happens at times that the same thing is both small and great. For the same thing may be small in comparison
with one thing, and great in comparison with another, so that the same thing comes to be both small and great
at one and the same time, and is of such a nature as to admit contrary qualities at one and the same moment.
Yet it was agreed, when substance was being discussed, that nothing admits contrary qualities at one and the
same moment. For though substance is capable of admitting contrary qualities, yet no one is at the same time
both sick and healthy, nothing is at the same time both white and black. Nor is there anything which is
qualified in contrary ways at one and the same time.

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The Categories

Moreover, if these were contraries, they would themselves be contrary to themselves. For if 'great' is the
contrary of 'small', and the same thing is both great and small at the same time, then 'small' or 'great' is the
contrary of itself. But this is impossible. The term 'great', therefore, is not the contrary of the term 'small', nor
'much' of 'little'. And even though a man should call these terms not relative but quantitative, they would not
have contraries.

It is in the case of space that quantity most plausibly appears to admit of a contrary. For men define the term
'above' as the contrary of 'below', when it is the region at the centre they mean by 'below'; and this is so,
because nothing is farther from the extremities of the universe than the region at the centre. Indeed, it seems
that in defining contraries of every kind men have recourse to a spatial metaphor, for they say that those
things are contraries which, within the same class, are separated by the greatest possible distance.

Quantity does not, it appears, admit of variation of degree. One thing cannot be two cubits long in a greater
degree than another. Similarly with regard to number: what is 'three' is not more truly three than what is 'five'
is five; nor is one set of three more truly three than another set. Again, one period of time is not said to be
more truly time than another. Nor is there any other kind of quantity, of all that have been mentioned, with
regard to which variation of degree can be predicated. The category of quantity, therefore, does not admit of
variation of degree.

The most distinctive mark of quantity is that equality and inequality are predicated of it. Each of the aforesaid
quantities is said to be equal or unequal. For instance, one solid is said to be equal or unequal to another;
number, too, and time can have these terms applied to them, indeed can all those kinds of quantity that have
been mentioned.

That which is not a quantity can by no means, it would seem, be termed equal or unequal to anything else.
One particular disposition or one particular quality, such as whiteness, is by no means compared with another
in terms of equality and inequality but rather in terms of similarity. Thus it is the distinctive mark of quantity
that it can be called equal and unequal.

Section 2

Part 7

Those things are called relative, which, being either said to be of something else or related to something else,
are explained by reference to that other thing. For instance, the word 'superior' is explained by reference to
something else, for it is superiority over something else that is meant. Similarly, the expression 'double' has
this external reference, for it is the double of something else that is meant. So it is with everything else of this
kind. There are, moreover, other relatives, e.g. habit, disposition, perception, knowledge, and attitude. The
significance of all these is explained by a reference to something else and in no other way. Thus, a habit is a
habit of something, knowledge is knowledge of something, attitude is the attitude of something. So it is with
all other relatives that have been mentioned. Those terms, then, are called relative, the nature of which is
explained by reference to something else, the preposition 'of or some other preposition being used to indicate
the relation. Thus, one mountain is called great in comparison with son with another; for the mountain claims
this attribute by comparison with something. Again, that which is called similar must be similar to something
else, and all other such attributes have this external reference. It is to be noted that lying and standing and
sitting are particular attitudes, but attitude is itself a relative term. To lie, to stand, to be seated, are not
themselves attitudes, but take their name from the aforesaid attitudes.

It is possible for relatives to have contraries. Thus virtue has a contrary, vice, these both being relatives;
knowledge, too, has a contrary, ignorance. But this is not the mark of all relatives; 'double' and 'triple' have no

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contrary, nor indeed has any such term.

It also appears that relatives can admit of variation of degree. For 'like' and 'unlike', 'equal' and 'unequal', have
the modifications 'more' and 'less' applied to them, and each of these is relative in character: for the terms
'like' and 'unequal' bear 'unequal' bear a reference to something external. Yet, again, it is not every relative
term that admits of variation of degree. No term such as 'double' admits of this modification. All relatives
have correlatives: by the term 'slave' we mean the slave of a master, by the term 'master', the master of a
slave; by 'double', the double of its hall; by 'half, the half of its double; by 'greater', greater than that which is
less; by 'less,' less than that which is greater.

So it is with every other relative term; but the case we use to express the correlation differs in some instances.
Thus, by knowledge we mean knowledge the knowable; by the knowable, that which is to be apprehended by
knowledge; by perception, perception of the perceptible; by the perceptible, that which is apprehended by
perception.

Sometimes, however, reciprocity of correlation does not appear to exist. This comes about when a blunder is
made, and that to which the relative is related is not accurately stated. If a man states that a wing is
necessarily relative to a bird, the connexion between these two will not be reciprocal, for it will not be
possible to say that a bird is a bird by reason of its wings. The reason is that the original statement was
inaccurate, for the wing is not said to be relative to the bird qua bird, since many creatures besides birds have
wings, but qua winged creature. If, then, the statement is made accurate, the connexion will be reciprocal, for
we can speak of a wing, having reference necessarily to a winged creature, and of a winged creature as being
such because of its wings.

Occasionally, perhaps, it is necessary to coin words, if no word exists by which a correlation can adequately
be explained. If we define a rudder as necessarily having reference to a boat, our definition will not be
appropriate, for the rudder does not have this reference to a boat qua boat, as there are boats which have no
rudders. Thus we cannot use the terms reciprocally, for the word 'boat' cannot be said to find its explanation
in the word 'rudder'. As there is no existing word, our definition would perhaps be more accurate if we coined
some word like 'ruddered' as the correlative of 'rudder'. If we express ourselves thus accurately, at any rate the
terms are reciprocally connected, for the 'ruddered' thing is 'ruddered' in virtue of its rudder. So it is in all
other cases. A head will be more accurately defined as the correlative of that which is 'headed', than as that of
an animal, for the animal does not have a head qua animal, since many animals have no head.

Thus we may perhaps most easily comprehend that to which a thing is related, when a name does not exist, if,
from that which has a name, we derive a new name, and apply it to that with which the first is reciprocally
connected, as in the aforesaid instances, when we derived the word 'winged' from 'wing' and from 'rudder'.

All relatives, then, if properly defined, have a correlative. I add this condition because, if that to which they
are related is stated as haphazard and not accurately, the two are not found to be interdependent. Let me state
what I mean more clearly. Even in the case of acknowledged correlatives, and where names exist for each,
there will be no interdependence if one of the two is denoted, not by that name which expresses the
correlative notion, but by one of irrelevant significance. The term 'slave,' if defined as related, not to a master,
but to a man, or a biped, or anything of that sort, is not reciprocally connected with that in relation to which it
is defined, for the statement is not exact. Further, if one thing is said to be correlative with another, and the
terminology used is correct, then, though all irrelevant attributes should be removed, and only that one
attribute left in virtue of which it was correctly stated to be correlative with that other, the stated correlation
will still exist. If the correlative of 'the slave' is said to be 'the master', then, though all irrelevant attributes of
the said 'master', such as 'biped', 'receptive of knowledge', 'human', should be removed, and the attribute
'master' alone left, the stated correlation existing between him and the slave will remain the same, for it is of a
master that a slave is said to be the slave. On the other hand, if, of two correlatives, one is not correctly

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The Categories

termed, then, when all other attributes are removed and that alone is left in virtue of which it was stated to be
correlative, the stated correlation will be found to have disappeared.

For suppose the correlative of 'the slave' should be said to be 'the man', or the correlative of 'the wing"the
bird'; if the attribute 'master' be withdrawn from' the man', the correlation between 'the man' and 'the slave'
will cease to exist, for if the man is not a master, the slave is not a slave. Similarly, if the attribute 'winged' be
withdrawn from 'the bird', 'the wing' will no longer be relative; for if the so-called correlative is not winged,
it follows that 'the wing' has no correlative.

Thus it is essential that the correlated terms should be exactly designated; if there is a name existing, the
statement will be easy; if not, it is doubtless our duty to construct names. When the terminology is thus
correct, it is evident that all correlatives are interdependent.

Correlatives are thought to come into existence simultaneously. This is for the most part true, as in the case of
the double and the half. The existence of the half necessitates the existence of that of which it is a half.
Similarly the existence of a master necessitates the existence of a slave, and that of a slave implies that of a
master; these are merely instances of a general rule. Moreover, they cancel one another; for if there is no
double it follows that there is no half, and vice versa; this rule also applies to all such correlatives. Yet it does
not appear to be true in all cases that correlatives come into existence simultaneously. The object of
knowledge would appear to exist before knowledge itself, for it is usually the case that we acquire knowledge
of objects already existing; it would be difficult, if not impossible, to find a branch of knowledge the
beginning of the existence of which was contemporaneous with that of its object.

Again, while the object of knowledge, if it ceases to exist, cancels at the same time the knowledge which was
its correlative, the converse of this is not true. It is true that if the object of knowledge does not exist there can
be no knowledge: for there will no longer be anything to know. Yet it is equally true that, if knowledge of a
certain object does not exist, the object may nevertheless quite well exist. Thus, in the case of the squaring of
the circle, if indeed that process is an object of knowledge, though it itself exists as an object of knowledge,
yet the knowledge of it has not yet come into existence. Again, if all animals ceased to exist, there would be
no knowledge, but there might yet be many objects of knowledge.

This is likewise the case with regard to perception: for the object of perception is, it appears, prior to the act
of perception. If the perceptible is annihilated, perception also will cease to exist; but the annihilation of
perception does not cancel the existence of the perceptible. For perception implies a body perceived and a
body in which perception takes place. Now if that which is perceptible is annihilated, it follows that the body
is annihilated, for the body is a perceptible thing; and if the body does not exist, it follows that perception
also ceases to exist. Thus the annihilation of the perceptible involves that of perception.

But the annihilation of perception does not involve that of the perceptible. For if the animal is annihilated, it
follows that perception also is annihilated, but perceptibles such as body, heat, sweetness, bitterness, and so
on, will remain.

Again, perception is generated at the same time as the perceiving subject, for it comes into existence at the
same time as the animal. But the perceptible surely exists before perception; for fire and water and such
elements, out of which the animal is itself composed, exist before the animal is an animal at all, and before
perception. Thus it would seem that the perceptible exists before perception.

It may be questioned whether it is true that no substance is relative, as seems to be the case, or whether
exception is to be made in the case of certain secondary substances. With regard to primary substances, it is
quite true that there is no such possibility, for neither wholes nor parts of primary substances are relative. The
individual man or ox is not defined with reference to something external. Similarly with the parts: a particular

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The Categories

hand or head is not defined as a particular hand or head of a particular person, but as the hand or head of a
particular person. It is true also, for the most part at least, in the case of secondary substances; the species
'man' and the species 'ox' are not defined with reference to anything outside themselves. Wood, again, is only
relative in so far as it is some one's property, not in so far as it is wood. It is plain, then, that in the cases
mentioned substance is not relative. But with regard to some secondary substances there is a difference of
opinion; thus, such terms as 'head' and 'hand' are defined with reference to that of which the things indicated
are a part, and so it comes about that these appear to have a relative character. Indeed, if our definition of that
which is relative was complete, it is very difficult, if not impossible, to prove that no substance is relative. If,
however, our definition was not complete, if those things only are properly called relative in the case of
which relation to an external object is a necessary condition of existence, perhaps some explanation of the
dilemma may be found.

The former definition does indeed apply to all relatives, but the fact that a thing is explained with reference to
something else does not make it essentially relative.

>From this it is plain that, if a man definitely apprehends a relative thing, he will also definitely apprehend
that to which it is relative. Indeed this is self-evident: for if a man knows that some particular thing is
relative, assuming that we call that a relative in the case of which relation to something is a necessary
condition of existence, he knows that also to which it is related. For if he does not know at all that to which it
is related, he will not know whether or not it is relative. This is clear, moreover, in particular instances. If a
man knows definitely that such and such a thing is 'double', he will also forthwith know definitely that of
which it is the double. For if there is nothing definite of which he knows it to be the double, he does not know
at all that it is double. Again, if he knows that a thing is more beautiful, it follows necessarily that he will
forthwith definitely know that also than which it is more beautiful. He will not merely know indefinitely that
it is more beautiful than something which is less beautiful, for this would be supposition, not knowledge. For
if he does not know definitely that than which it is more beautiful, he can no longer claim to know definitely
that it is more beautiful than something else which is less beautiful: for it might be that nothing was less
beautiful. It is, therefore, evident that if a man apprehends some relative thing definitely, he necessarily
knows that also definitely to which it is related.

Now the head, the hand, and such things are substances, and it is possible to know their essential character
definitely, but it does not necessarily follow that we should know that to which they are related. It is not
possible to know forthwith whose head or hand is meant. Thus these are not relatives, and, this being the
case, it would be true to say that no substance is relative in character. It is perhaps a difficult matter, in such
cases, to make a positive statement without more exhaustive examination, but to have raised questions with
regard to details is not without advantage.

Part 8

By 'quality' I mean that in virtue of which people are said to be such and such.

Quality is a term that is used in many senses. One sort of quality let us call 'habit' or 'disposition'. Habit
differs from disposition in being more lasting and more firmly established. The various kinds of knowledge
and of virtue are habits, for knowledge, even when acquired only in a moderate degree, is, it is agreed,
abiding in its character and difficult to displace, unless some great mental upheaval takes place, through
disease or any such cause. The virtues, also, such as justice, self-restraint, and so on, are not easily dislodged
or dismissed, so as to give place to vice.

By a disposition, on the other hand, we mean a condition that is easily changed and quickly gives place to its
opposite. Thus, heat, cold, disease, health, and so on are dispositions. For a man is disposed in one way or

Part 8 1 1

The Categories

another with reference to these, but quickly changes, becoming cold instead of warm, ill instead of well. So it
is with all other dispositions also, unless through lapse of time a disposition has itself become inveterate and
almost impossible to dislodge: in which case we should perhaps go so far as to call it a habit.

It is evident that men incline to call those conditions habits which are of a more or less permanent type and
difficult to displace; for those who are not retentive of knowledge, but volatile, are not said to have such and
such a 'habit' as regards knowledge, yet they are disposed, we may say, either better or worse, towards
knowledge. Thus habit differs from disposition in this, that while the latter in ephemeral, the former is
permanent and difficult to alter.

Habits are at the same time dispositions, but dispositions are not necessarily habits. For those who have some
specific habit may be said also, in virtue of that habit, to be thus or thus disposed; but those who are disposed
in some specific way have not in all cases the corresponding habit.

Another sort of quality is that in virtue of which, for example, we call men good boxers or runners, or healthy
or sickly: in fact it includes all those terms which refer to inborn capacity or incapacity. Such things are not
predicated of a person in virtue of his disposition, but in virtue of his inborn capacity or incapacity to do
something with ease or to avoid defeat of any kind. Persons are called good boxers or good runners, not in
virtue of such and such a disposition, but in virtue of an inborn capacity to accomplish something with ease.
Men are called healthy in virtue of the inborn capacity of easy resistance to those unhealthy influences that
may ordinarily arise; unhealthy, in virtue of the lack of this capacity. Similarly with regard to softness and
hardness. Hardness is predicated of a thing because it has that capacity of resistance which enables it to
withstand disintegration; softness, again, is predicated of a thing by reason of the lack of that capacity.

A third class within this category is that of affective qualities and affections. Sweetness, bitterness, sourness,
are examples of this sort of quality, together with all that is akin to these; heat, moreover, and cold,
whiteness, and blackness are affective qualities. It is evident that these are qualities, for those things that
possess them are themselves said to be such and such by reason of their presence. Honey is called sweet
because it contains sweetness; the body is called white because it contains whiteness; and so in all other
cases.

The term 'affective quality' is not used as indicating that those things which admit these qualities are affected
in any way. Honey is not called sweet because it is affected in a specific way, nor is this what is meant in any
other instance. Similarly heat and cold are called affective qualities, not because those things which admit
them are affected. What is meant is that these said qualities are capable of producing an 'affection' in the way
of perception. For sweetness has the power of affecting the sense of taste; heat, that of touch; and so it is with
the rest of these qualities.

Whiteness and blackness, however, and the other colours, are not said to be affective qualities in this sense,
but -because they themselves are the results of an affection. It is plain that many changes of colour take place
because of affections. When a man is ashamed, he blushes; when he is afraid, he becomes pale, and so on. So
true is this, that when a man is by nature liable to such affections, arising from some concomitance of
elements in his constitution, it is a probable inference that he has the corresponding complexion of skin. For
the same disposition of bodily elements, which in the former instance was momentarily present in the case of
an access of shame, might be a result of a man's natural temperament, so as to produce the corresponding
colouring also as a natural characteristic. All conditions, therefore, of this kind, if caused by certain
permanent and lasting affections, are called affective qualities. For pallor and duskiness of complexion are
called qualities, inasmuch as we are said to be such and such in virtue of them, not only if they originate in
natural constitution, but also if they come about through long disease or sunburn, and are difficult to remove,
or indeed remain throughout life. For in the same way we are said to be such and such because of these.

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The Categories

Those conditions, however, which arise from causes which may easily be rendered ineffective or speedily
removed, are called, not qualities, but affections: for we are not said to be such virtue of them. The man who
blushes through shame is not said to be a constitutional blusher, nor is the man who becomes pale through
fear said to be constitutionally pale. He is said rather to have been affected.

Thus such conditions are called affections, not qualities. In like manner there are affective qualities and
affections of the soul. That temper with which a man is born and which has its origin in certain deep-seated
affections is called a quality. I mean such conditions as insanity, irascibility, and so on: for people are said to
be mad or irascible in virtue of these. Similarly those abnormal psychic states which are not inborn, but arise
from the concomitance of certain other elements, and are difficult to remove, or altogether permanent, are
called qualities, for in virtue of them men are said to be such and such.

Those, however, which arise from causes easily rendered ineffective are called affections, not qualities.
Suppose that a man is irritable when vexed: he is not even spoken of as a bad-tempered man, when in such
circumstances he loses his temper somewhat, but rather is said to be affected. Such conditions are therefore
termed, not qualities, but affections.

The fourth sort of quality is figure and the shape that belongs to a thing; and besides this, straightness and
curvedness and any other qualities of this type; each of these defines a thing as being such and such. Because
it is triangular or quadrangular a thing is said to have a specific character, or again because it is straight or
curved; in fact a thing's shape in every case gives rise to a qualification of it.

Rarity and density, roughness and smoothness, seem to be terms indicating quality: yet these, it would
appear, really belong to a class different from that of quality. For it is rather a certain relative position of the
parts composing the thing thus qualified which, it appears, is indicated by each of these terms. A thing is
dense, owing to the fact that its parts are closely combined with one another; rare, because there are
interstices between the parts; smooth, because its parts lie, so to speak, evenly; rough, because some parts
project beyond others.

There may be other sorts of quality, but those that are most properly so called have, we may safely say, been
enumerated.

These, then, are qualities, and the things that take their name from them as derivatives, or are in some other
way dependent on them, are said to be qualified in some specific way. In most, indeed in almost all cases, the
name of that which is qualified is derived from that of the quality. Thus the terms 'whiteness', 'grammar',
'justice', give us the adjectives 'white', 'grammatical', just', and so on.

There are some cases, however, in which, as the quality under consideration has no name, it is impossible that
those possessed of it should have a name that is derivative. For instance, the name given to the runner or
boxer, who is so called in virtue of an inborn capacity, is not derived from that of any quality; for lob those
capacities have no name assigned to them. In this, the inborn capacity is distinct from the science, with
reference to which men are called, e.g. boxers or wrestlers. Such a science is classed as a disposition; it has a
name, and is called 'boxing' or 'wrestling' as the case may be, and the name given to those disposed in this
way is derived from that of the science. Sometimes, even though a name exists for the quality, that which
takes its character from the quality has a name that is not a derivative. For instance, the upright man takes his
character from the possession of the quality of integrity, but the name given him is not derived from the word
'integrity'. Yet this does not occur often.

We may therefore state that those things are said to be possessed of some specific quality which have a name
derived from that of the aforesaid quality, or which are in some other way dependent on it.

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The Categories

One quality may be the contrary of another; thus justice is the contrary of injustice, whiteness of blackness,
and so on. The things, also, which are said to be such and such in virtue of these qualities, may be contrary
the one to the other; for that which is unjust is contrary to that which is just, that which is white to that which
is black. This, however, is not always the case. Red, yellow, and such colours, though qualities, have no
contraries.

If one of two contraries is a quality, the other will also be a quality. This will be evident from particular
instances, if we apply the names used to denote the other categories; for instance, granted that justice is the
contrary of injustice and justice is a quality, injustice will also be a quality: neither quantity, nor relation, nor
place, nor indeed any other category but that of quality, will be applicable properly to injustice. So it is with
all other contraries falling under the category of quality.

Qualities admit of variation of degree. Whiteness is predicated of one thing in a greater or less degree than of
another. This is also the case with reference to justice. Moreover, one and the same thing may exhibit a
quality in a greater degree than it did before: if a thing is white, it may become whiter.

Though this is generally the case, there are exceptions. For if we should say that justice admitted of variation
of degree, difficulties might ensue, and this is true with regard to all those qualities which are dispositions.
There are some, indeed, who dispute the possibility of variation here. They maintain that justice and health
cannot very well admit of variation of degree themselves, but that people vary in the degree in which they
possess these qualities, and that this is the case with grammatical learning and all those qualities which are
classed as dispositions. However that may be, it is an incontrovertible fact that the things which in virtue of
these qualities are said to be what they are vary in the degree in which they possess them; for one man is said
to be better versed in grammar, or more healthy or just, than another, and so on.

The qualities expressed by the terms 'triangular' and 'quadrangular' do not appear to admit of variation of
degree, nor indeed do any that have to do with figure. For those things to which the definition of the triangle
or circle is applicable are all equally triangular or circular. Those, on the other hand, to which the same
definition is not applicable, cannot be said to differ from one another in degree; the square is no more a circle
than the rectangle, for to neither is the definition of the circle appropriate. In short, if the definition of the
term proposed is not applicable to both objects, they cannot be compared. Thus it is not all qualities which
admit of variation of degree.

Whereas none of the characteristics I have mentioned are peculiar to quality, the fact that likeness and
unlikeness can be predicated with reference to quality only, gives to that category its distinctive feature. One
thing is like another only with reference to that in virtue of which it is such and such; thus this forms the
peculiar mark of quality.

We must not be disturbed because it may be argued that, though proposing to discuss the category of quality,
we have included in it many relative terms. We did say that habits and dispositions were relative. In
practically all such cases the genus is relative, the individual not. Thus knowledge, as a genus, is explained by
reference to something else, for we mean a knowledge of something. But particular branches of knowledge
are not thus explained. The knowledge of grammar is not relative to anything external, nor is the knowledge
of music, but these, if relative at all, are relative only in virtue of their genera; thus grammar is said be the
knowledge of something, not the grammar of something; similarly music is the knowledge of something, not
the music of something.

Thus individual branches of knowledge are not relative. And it is because we possess these individual
branches of knowledge that we are said to be such and such. It is these that we actually possess: we are called
experts because we possess knowledge in some particular branch. Those particular branches, therefore, of
knowledge, in virtue of which we are sometimes said to be such and such, are themselves qualities, and are

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not relative. Further, if anything should happen to fall within both the category of quality and that of relation,
there would be nothing extraordinary in classing it under both these heads.

Section 3

Part 9

Action and affection both admit of contraries and also of variation of degree. Heating is the contrary of
cooling, being heated of being cooled, being glad of being vexed. Thus they admit of contraries. They also
admit of variation of degree: for it is possible to heat in a greater or less degree; also to be heated in a greater
or less degree. Thus action and affection also admit of variation of degree. So much, then, is stated with
regard to these categories.

We spoke, moreover, of the category of position when we were dealing with that of relation, and stated that
such terms derived their names from those of the corresponding attitudes.

As for the rest, time, place, state, since they are easily intelligible, I say no more about them than was said at
the beginning, that in the category of state are included such states as 'shod', 'armed', in that of place 'in the
Lyceum' and so on, as was explained before.

Part 10

The proposed categories have, then, been adequately dealt with. We must next explain the various senses in
which the term 'opposite' is used. Things are said to be opposed in four senses: (i) as correlatives to one
another, (ii) as contraries to one another, (iii) as privatives to positives, (iv) as affirmatives to negatives.

Let me sketch my meaning in outline. An instance of the use of the word 'opposite' with reference to
correlatives is afforded by the expressions 'double' and 'half ; with reference to contraries by 'bad' and 'good'.
Opposites in the sense of 'privatives' and 'positives' are' blindness' and 'sight'; in the sense of affirmatives and
negatives, the propositions 'he sits', 'he does not sit'.

(i) Pairs of opposites which fall under the category of relation are explained by a reference of the one to the
other, the reference being indicated by the preposition 'of or by some other preposition. Thus, double is a
relative term, for that which is double is explained as the double of something. Knowledge, again, is the
opposite of the thing known, in the same sense; and the thing known also is explained by its relation to its
opposite, knowledge. For the thing known is explained as that which is known by something, that is, by
knowledge. Such things, then, as are opposite the one to the other in the sense of being correlatives are
explained by a reference of the one to the other.

(ii) Pairs of opposites which are contraries are not in any way interdependent, but are contrary the one to the
other. The good is not spoken of as the good of the had, but as the contrary of the bad, nor is white spoken of
as the white of the black, but as the contrary of the black. These two types of opposition are therefore distinct.
Those contraries which are such that the subjects in which they are naturally present, or of which they are
predicated, must necessarily contain either the one or the other of them, have no intermediate, but those in the
case of which no such necessity obtains, always have an intermediate. Thus disease and health are naturally
present in the body of an animal, and it is necessary that either the one or the other should be present in the
body of an animal. Odd and even, again, are predicated of number, and it is necessary that the one or the
other should be present in numbers. Now there is no intermediate between the terms of either of these two
pairs. On the other hand, in those contraries with regard to which no such necessity obtains, we find an
intermediate. Blackness and whiteness are naturally present in the body, but it is not necessary that either the

Section 3 15

The Categories

one or the other should be present in the body, inasmuch as it is not true to say that everybody must be white
or black. Badness and goodness, again, are predicated of man, and of many other things, but it is not
necessary that either the one quality or the other should be present in that of which they are predicated: it is
not true to say that everything that may be good or bad must be either good or bad. These pairs of contraries
have intermediates: the intermediates between white and black are grey, sallow, and all the other colours that
come between; the intermediate between good and bad is that which is neither the one nor the other.

Some intermediate qualities have names, such as grey and sallow and all the other colours that come between
white and black; in other cases, however, it is not easy to name the intermediate, but we must define it as that
which is not either extreme, as in the case of that which is neither good nor bad, neither just nor unjust.

(iii) 'privatives' and 'Positives' have reference to the same subject. Thus, sight and blindness have reference to
the eye. It is a universal rule that each of a pair of opposites of this type has reference to that to which the
particular 'positive' is natural. We say that that is capable of some particular faculty or possession has suffered
privation when the faculty or possession in question is in no way present in that in which, and at the time at
which, it should naturally be present. We do not call that toothless which has not teeth, or that blind which
has not sight, but rather that which has not teeth or sight at the time when by nature it should. For there are
some creatures which from birth are without sight, or without teeth, but these are not called toothless or blind.

To be without some faculty or to possess it is not the same as the corresponding 'privative' or 'positive'. 'Sight'
is a 'positive', 'blindness' a 'privative', but 'to possess sight' is not equivalent to 'sight', 'to be blind' is not
equivalent to 'blindness'. Blindness is a 'privative', to be blind is to be in a state of privation, but is not a
'privative'. Moreover, if 'blindness' were equivalent to 'being blind', both would be predicated of the same
subject; but though a man is said to be blind, he is by no means said to be blindness.

To be in a state of 'possession' is, it appears, the opposite of being in a state of 'privation', just as 'positives'
and 'privatives' themselves are opposite. There is the same type of antithesis in both cases; for just as
blindness is opposed to sight, so is being blind opposed to having sight.

That which is affirmed or denied is not itself affirmation or denial. By 'affirmation' we mean an affirmative
proposition, by 'denial' a negative. Now, those facts which form the matter of the affirmation or denial are not
propositions; yet these two are said to be opposed in the same sense as the affirmation and denial, for in this
case also the type of antithesis is the same. For as the affirmation is opposed to the denial, as in the two
propositions 'he sits', 'he does not sit', so also the fact which constitutes the matter of the proposition in one
case is opposed to that in the other, his sitting, that is to say, to his not sitting.

It is evident that 'positives' and 'privatives' are not opposed each to each in the same sense as relatives. The
one is not explained by reference to the other; sight is not sight of blindness, nor is any other preposition used
to indicate the relation. Similarly blindness is not said to be blindness of sight, but rather, privation of sight.
Relatives, moreover, reciprocate; if blindness, therefore, were a relative, there would be a reciprocity of
relation between it and that with which it was correlative. But this is not the case. Sight is not called the sight
of blindness.

That those terms which fall under the heads of 'positives' and 'privatives' are not opposed each to each as
contraries, either, is plain from the following facts: Of a pair of contraries such that they have no
intermediate, one or the other must needs be present in the subject in which they naturally subsist, or of which
they are predicated; for it is those, as we proved,' in the case of which this necessity obtains, that have no
intermediate. Moreover, we cited health and disease, odd and even, as instances. But those contraries which
have an intermediate are not subject to any such necessity. It is not necessary that every substance, receptive
of such qualities, should be either black or white, cold or hot, for something intermediate between these
contraries may very well be present in the subject. We proved, moreover, that those contraries have an

Section 3 16

The Categories

intermediate in the case of which the said necessity does not obtain. Yet when one of the two contraries is a
constitutive property of the subject, as it is a constitutive property of fire to be hot, of snow to be white, it is
necessary determinately that one of the two contraries, not one or the other, should be present in the subject;
for fire cannot be cold, or snow black. Thus, it is not the case here that one of the two must needs be present
in every subject receptive of these qualities, but only in that subject of which the one forms a constitutive
property. Moreover, in such cases it is one member of the pair determinately, and not either the one or the
other, which must be present.

In the case of 'positives' and 'privatives', on the other hand, neither of the aforesaid statements holds good. For
it is not necessary that a subject receptive of the qualities should always have either the one or the other; that
which has not yet advanced to the state when sight is natural is not said either to be blind or to see. Thus
'positives' and 'privatives' do not belong to that class of contraries which consists of those which have no
intermediate. On the other hand, they do not belong either to that class which consists of contraries which
have an intermediate. For under certain conditions it is necessary that either the one or the other should form
part of the constitution of every appropriate subject. For when a thing has reached the stage when it is by
nature capable of sight, it will be said either to see or to be blind, and that in an indeterminate sense,
signifying that the capacity may be either present or absent; for it is not necessary either that it should see or
that it should be blind, but that it should be either in the one state or in the other. Yet in the case of those
contraries which have an intermediate we found that it was never necessary that either the one or the other
should be present in every appropriate subject, but only that in certain subjects one of the pair should be
present, and that in a determinate sense. It is, therefore, plain that 'positives' and 'privatives' are not opposed
each to each in either of the senses in which contraries are opposed.

Again, in the case of contraries, it is possible that there should be changes from either into the other, while the
subject retains its identity, unless indeed one of the contraries is a constitutive property of that subject, as heat
is of fire. For it is possible that that that which is healthy should become diseased, that which is white, black,
that which is cold, hot, that which is good, bad, that which is bad, good. The bad man, if he is being brought
into a better way of life and thought, may make some advance, however slight, and if he should once
improve, even ever so little, it is plain that he might change completely, or at any rate make very great
progress; for a man becomes more and more easily moved to virtue, however small the improvement was at
first. It is, therefore, natural to suppose that he will make yet greater progress than he has made in the past;
and as this process goes on, it will change him completely and establish him in the contrary state, provided he
is not hindered by lack of time. In the case of 'positives' and 'privatives', however, change in both directions is
impossible. There may be a change from possession to privation, but not from privation to possession. The
man who has become blind does not regain his sight; the man who has become bald does not regain his hair;
the man who has lost his teeth does not grow his grow a new set. (iv) Statements opposed as affirmation and
negation belong manifestly to a class which is distinct, for in this case, and in this case only, it is necessary
for the one opposite to be true and the other false.

Neither in the case of contraries, nor in the case of correlatives, nor in the case of 'positives' and 'privatives', is
it necessary for one to be true and the other false. Health and disease are contraries: neither of them is true or
false. 'Double' and 'half are opposed to each other as correlatives: neither of them is true or false. The case is
the same, of course, with regard to 'positives' and 'privatives' such as 'sight' and 'blindness'. In short, where
there is no sort of combination of words, truth and falsity have no place, and all the opposites we have
mentioned so far consist of simple words.

At the same time, when the words which enter into opposed statements are contraries, these, more than any
other set of opposites, would seem to claim this characteristic. 'Socrates is ill' is the contrary of 'Socrates is
well', but not even of such composite expressions is it true to say that one of the pair must always be true and
the other false. For if Socrates exists, one will be true and the other false, but if he does not exist, both will be
false; for neither 'Socrates is ill' nor 'Socrates is well' is true, if Socrates does not exist at all.

Section 3 17

The Categories

In the case of 'positives' and 'privatives', if the subject does not exist at all, neither proposition is true, but
even if the subject exists, it is not always the fact that one is true and the other false. For 'Socrates has sight' is
the opposite of 'Socrates is blind' in the sense of the word 'opposite' which applies to possession and
privation. Now if Socrates exists, it is not necessary that one should be true and the other false, for when he is
not yet able to acquire the power of vision, both are false, as also if Socrates is altogether non-existent.

But in the case of affirmation and negation, whether the subject exists or not, one is always false and the
other true. For manifestly, if Socrates exists, one of the two propositions 'Socrates is ill', 'Socrates is not ill', is
true, and the other false. This is likewise the case if he does not exist; for if he does not exist, to say that he is
ill is false, to say that he is not ill is true. Thus it is in the case of those opposites only, which are opposite in
the sense in which the term is used with reference to affirmation and negation, that the rule holds good, that
one of the pair must be true and the other false.

Part 11

That the contrary of a good is an evil is shown by induction: the contrary of health is disease, of courage,
cowardice, and so on. But the contrary of an evil is sometimes a good, sometimes an evil. For defect, which is
an evil, has excess for its contrary, this also being an evil, and the mean, which is a good, is equally the
contrary of the one and of the other. It is only in a few cases, however, that we see instances of this: in most,
the contrary of an evil is a good.

In the case of contraries, it is not always necessary that if one exists the other should also exist: for if all
become healthy there will be health and no disease, and again, if everything turns white, there will be white,
but no black. Again, since the fact that Socrates is ill is the contrary of the fact that Socrates is well, and two
contrary conditions cannot both obtain in one and the same individual at the same time, both these contraries
could not exist at once: for if that Socrates was well was a fact, then that Socrates was ill could not possibly
be one.

It is plain that contrary attributes must needs be present in subjects which belong to the same species or
genus. Disease and health require as their subject the body of an animal; white and black require a body,
without further qualification; justice and injustice require as their subject the human soul.

Moreover, it is necessary that pairs of contraries should in all cases either belong to the same genus or belong
to contrary genera or be themselves genera. White and black belong to the same genus, colour; justice and
injustice, to contrary genera, virtue and vice; while good and evil do not belong to genera, but are themselves
actual genera, with terms under them.

Part 12

There are four senses in which one thing can be said to be 'prior' to another. Primarily and most properly the
term has reference to time: in this sense the word is used to indicate that one thing is older or more ancient
than another, for the expressions 'older' and 'more ancient' imply greater length of time.

Secondly, one thing is said to be 'prior' to another when the sequence of their being cannot be reversed. In this
sense 'one' is 'prior' to 'two'. For if 'two' exists, it follows directly that 'one' must exist, but if 'one' exists, it
does not follow necessarily that 'two' exists: thus the sequence subsisting cannot be reversed. It is agreed,
then, that when the sequence of two things cannot be reversed, then that one on which the other depends is
called 'prior' to that other.

Part 11 18

The Categories

In the third place, the term 'prior' is used with reference to any order, as in the case of science and of oratory.
For in sciences which use demonstration there is that which is prior and that which is posterior in order; in
geometry, the elements are prior to the propositions; in reading and writing, the letters of the alphabet are
prior to the syllables. Similarly, in the case of speeches, the exordium is prior in order to the narrative.

Besides these senses of the word, there is a fourth. That which is better and more honourable is said to have a
natural priority. In common parlance men speak of those whom they honour and love as 'coming first' with
them. This sense of the word is perhaps the most far-fetched.

Such, then, are the different senses in which the term 'prior' is used.

Yet it would seem that besides those mentioned there is yet another. For in those things, the being of each of
which implies that of the other, that which is in any way the cause may reasonably be said to be by nature
'prior' to the effect. It is plain that there are instances of this. The fact of the being of a man carries with it the
truth of the proposition that he is, and the implication is reciprocal: for if a man is, the proposition wherein
we allege that he is true, and conversely, if the proposition wherein we allege that he is true, then he is. The
true proposition, however, is in no way the cause of the being of the man, but the fact of the man's being does
seem somehow to be the cause of the truth of the proposition, for the truth or falsity of the proposition
depends on the fact of the man's being or not being.

Thus the word 'prior' may be used in five senses.

Part 13

The term 'simultaneous' is primarily and most appropriately applied to those things the genesis of the one of
which is simultaneous with that of the other; for in such cases neither is prior or posterior to the other. Such
things are said to be simultaneous in point of time. Those things, again, are 'simultaneous' in point of nature,
the being of each of which involves that of the other, while at the same time neither is the cause of the other's
being. This is the case with regard to the double and the half, for these are reciprocally dependent, since, if
there is a double, there is also a half, and if there is a half, there is also a double, while at the same time
neither is the cause of the being of the other.

Again, those species which are distinguished one from another and opposed one to another within the same
genus are said to be 'simultaneous' in nature. I mean those species which are distinguished each from each by
one and the same method of division. Thus the 'winged' species is simultaneous with the 'terrestrial' and the
'water' species. These are distinguished within the same genus, and are opposed each to each, for the genus
'animal' has the 'winged', the 'terrestrial', and the 'water' species, and no one of these is prior or posterior to
another; on the contrary, all such things appear to be 'simultaneous' in nature. Each of these also, the
terrestrial, the winged, and the water species, can be divided again into subspecies. Those species, then, also
will be 'simultaneous' point of nature, which, belonging to the same genus, are distinguished each from each
by one and the same method of differentiation.

But genera are prior to species, for the sequence of their being cannot be reversed. If there is the species
'water-animal', there will be the genus 'animal', but granted the being of the genus 'animal', it does not follow
necessarily that there will be the species 'water-animal'.

Those things, therefore, are said to be 'simultaneous' in nature, the being of each of which involves that of the
other, while at the same time neither is in any way the cause of the other's being; those species, also, which
are distinguished each from each and opposed within the same genus. Those things, moreover, are
'simultaneous' in the unqualified sense of the word which come into being at the same time.

Part 13 19

The Categories

Part 14

There are six sorts of movement: generation, destruction, increase, diminution, alteration, and change of
place.

It is evident in all but one case that all these sorts of movement are distinct each from each. Generation is
distinct from destruction, increase and change of place from diminution, and so on. But in the case of
alteration it may be argued that the process necessarily implies one or other of the other five sorts of motion.
This is not true, for we may say that all affections, or nearly all, produce in us an alteration which is distinct
from all other sorts of motion, for that which is affected need not suffer either increase or diminution or any
of the other sorts of motion. Thus alteration is a distinct sort of motion; for, if it were not, the thing altered
would not only be altered, but would forthwith necessarily suffer increase or diminution or some one of the
other sorts of motion in addition; which as a matter of fact is not the case. Similarly that which was
undergoing the process of increase or was subject to some other sort of motion would, if alteration were not a
distinct form of motion, necessarily be subject to alteration also. But there are some things which undergo
increase but yet not alteration. The square, for instance, if a gnomon is applied to it, undergoes increase but
not alteration, and so it is with all other figures of this sort. Alteration and increase, therefore, are distinct.

Speaking generally, rest is the contrary of motion. But the different forms of motion have their own contraries
in other forms; thus destruction is the contrary of generation, diminution of increase, rest in a place, of change
of place. As for this last, change in the reverse direction would seem to be most truly its contrary; thus motion
upwards is the contrary of motion downwards and vice versa.

In the case of that sort of motion which yet remains, of those that have been enumerated, it is not easy to state
what is its contrary. It appears to have no contrary, unless one should define the contrary here also either as
'rest in its quality' or as 'change in the direction of the contrary quality', just as we defined the contrary of
change of place either as rest in a place or as change in the reverse direction. For a thing is altered when
change of quality takes place; therefore either rest in its quality or change in the direction of the contrary may
be called the contrary of this qualitative form of motion. In this way becoming white is the contrary of
becoming black; there is alteration in the contrary direction, since a change of a qualitative nature takes place.

Part 15

The term 'to have' is used in various senses. In the first place it is used with reference to habit or disposition
or any other quality, for we are said to 'have' a piece of knowledge or a virtue. Then, again, it has reference to
quantity, as, for instance, in the case of a man's height; for he is said to 'have' a height of three or four cubits.
It is used, moreover, with regard to apparel, a man being said to 'have' a coat or tunic; or in respect of
something which we have on a part of ourselves, as a ring on the hand: or in respect of something which is a
part of us, as hand or foot. The term refers also to content, as in the case of a vessel and wheat, or of a jar and
wine; ajar is said to 'have' wine, and a corn-measure wheat. The expression in such cases has reference to
content. Or it refers to that which has been acquired; we are said to 'have' a house or a field. A man is also
said to 'have' a wife, and a wife a husband, and this appears to be the most remote meaning of the term, for by
the use of it we mean simply that the husband lives with the wife.

Other senses of the word might perhaps be found, but the most ordinary ones have all been enumerated.

Part 14 20

ON DREAMS

by Aristotle

ON DREAMS

Table of Contents

ON DREAMS. 1

by Aristotle 1

_1 1

2 2

3 4

ON DREAMS

by Aristotle

translated by J. I. Beare

• 1
•2
•3

WE must, in the next place, investigate the subject of the dream, and first inquire to which of the faculties of
the soul it presents itself, i.e. whether the affection is one which pertains to the faculty of intelligence or to
that of sense-perception; for these are the only faculties within us by which we acquire knowledge.

If, then, the exercise of the faculty of sight is actual seeing, that of the auditory faculty, hearing, and, in
general that of the faculty of sense-perception, perceiving; and if there are some perceptions common to the
senses, such as figure, magnitude, motion, while there are others, as colour, sound, taste, peculiar [each to its
own sense]; and further, if all creatures, when the eyes are closed in sleep, are unable to see, and the
analogous statement is true of the other senses, so that manifestly we perceive nothing when asleep; we may
conclude that it is not by sense-perception we perceive a dream.

But neither is it by opinion that we do so. For [in dreams] we not only assert, e.g. that some object
approaching is a man or a horse [which would be an exercise of opinion], but that the object is white or
beautiful, points on which opinion without sense-perception asserts nothing either truly or falsely. It is,
however, a fact that the soul makes such assertions in sleep. We seem to see equally well that the approaching
figure is a man, and that it is white. [In dreams], too, we think something else, over and above the dream
presentation, just as we do in waking moments when we perceive something; for we often also reason about
that which we perceive. So, too, in sleep we sometimes have thoughts other than the mere phantasms
immediately before our minds. This would be manifest to any one who should attend and try, immediately on
arising from sleep, to remember [his dreaming experience]. There are cases of persons who have seen such
dreams, those, for example, who believe themselves to be mentally arranging a given list of subjects
according to the mnemonic rule. They frequently find themselves engaged in something else besides the
dream, viz. in setting a phantasm which they envisage into its mnemonic position. Hence it is plain that not
every 'phantasm' in sleep is a mere dream-image, and that the further thinking which we perform then is due
to an exercise of the faculty of opinion.

So much at least is plain on all these points, viz. that the faculty by which, in waking hours, we are subject to
illusion when affected by disease, is identical with that which produces illusory effects in sleep. So, even
when persons are in excellent health, and know the facts of the case perfectly well, the sun, nevertheless,
appears to them to be only a foot wide. Now, whether the presentative faculty of the soul be identical with, or

ON DREAMS 1

ON DREAMS

different from, the faculty of sense-perception, in either case the illusion does not occur without our actually
seeing or [otherwise] perceiving something. Even to see wrongly or to hear wrongly can happen only to one
who sees or hears something real, though not exactly what he supposes. But we have assumed that in sleep
one neither sees, nor hears, nor exercises any sense whatever. Perhaps we may regard it as true that the
dreamer sees nothing, yet as false that his faculty of sense-perception is unaffected, the fact being that the
sense of seeing and the other senses may possibly be then in a certain way affected, while each of these
affections, as duly as when he is awake, gives its impulse in a certain manner to his [primary] faculty of
sense, though not in precisely the same manner as when he is awake. Sometimes, too, opinion says [to
dreamers] just as to those who are awake, that the object seen is an illusion; at other times it is inhibited, and
becomes a mere follower of the phantasm.

It is plain therefore that this affection, which we name 'dreaming', is no mere exercise of opinion or
intelligence, but yet is not an affection of the faculty of perception in the simple sense. If it were the latter it
would be possible [when asleep] to hear and see in the simple sense.

How then, and in what manner, it takes place, is what we have to examine. Let us assume, what is indeed
clear enough, that the affection [of dreaming] pertains to sense-perception as surely as sleep itself does. For
sleep does not pertain to one organ in animals and dreaming to another; both pertain to the same organ.

But since we have, in our work On the Soul, treated of presentation, and the faculty of presentation is
identical with that of sense-perception, though the essential notion of a faculty of presentation is different
from that of a faculty of sense-perception; and since presentation is the movement set up by a sensory faculty
when actually discharging its function, while a dream appears to be a presentation (for a presentation which
occurs in sleep-whether simply or in some particular way-is what we call a dream): it manifestly follows
that dreaming is an activity of the faculty of sense-perception, but belongs to this faculty qua presentative.

We can best obtain a scientific view of the nature of the dream and the manner in which it originates by
regarding it in the light of the circumstances attending sleep. The objects of sense-perception corresponding
to each sensory organ produce sense-perception in us, and the affection due to their operation is present in
the organs of sense not only when the perceptions are actualized, but even when they have departed.

What happens in these cases may be compared with what happens in the case of projectiles moving in space.
For in the case of these the movement continues even when that which set up the movement is no longer in
contact [with the things that are moved]. For that which set them in motion moves a certain portion of air, and
this, in turn, being moved excites motion in another portion; and so, accordingly, it is in this way that [the
bodies], whether in air or in liquids, continue moving, until they come to a standstill.

This we must likewise assume to happen in the case of qualitative change; for that part which [for example]
has been heated by something hot, heats [in turn] the part next to it, and this propagates the affection
continuously onwards until the process has come round to its oint of origination. This must also happen in the
organ wherein the exercise of sense-perception takes place, since sense-perception, as realized in actual
perceiving, is a mode of qualitative change. This explains why the affection continues in the sensory organs,
both in their deeper and in their more superficial parts, not merely while they are actually engaged in
perceiving, but even after they have ceased to do so. That they do this, indeed, is obvious in cases where we
continue for some time engaged in a particular form of perception, for then, when we shift the scene of our
perceptive activity, the previous affection remains; for instance, when we have turned our gaze from sunlight
into darkness. For the result of this is that one sees nothing, owing to the excited by the light still subsisting in
our eyes. Also, when we have looked steadily for a long while at one colour, e.g. at white or green, that to

ON DREAMS

which we next transfer our gaze appears to be of the same colour. Again if, after having looked at the sun or
some other brilliant object, we close the eyes, then, if we watch carefully, it appears in a right line with the
direction of vision (whatever this may be), at first in its own colour; then it changes to crimson, next to
purple, until it becomes black and disappears. And also when persons turn away from looking at objects in
motion, e.g. rivers, and especially those which flow very rapidly, they find that the visual stimulations still
present themselves, for the things really at rest are then seen moving: persons become very deaf after hearing
loud noises, and after smelling very strong odours their power of smelling is impaired; and similarly in other
cases. These phenomena manifestly take place in the way above described.

That the sensory organs are acutely sensitive to even a slight qualitative difference [in their objects] is shown
by what happens in the case of mirrors; a subject to which, even taking it independently, one might devote
close consideration and inquiry. At the same time it becomes plain from them that as the eye [in seeing] is
affected [by the object seen], so also it produces a certain effect upon it. If a woman chances during her
menstrual period to look into a highly polished mirror, the surface of it will grow cloudy with a
blood-coloured haze. It is very hard to remove this stain from a new mirror, but easier to remove from an
older mirror. As we have said before, the cause of this lies in the fact that in the act of sight there occurs not
only a passion in the sense organ acted on by the polished surface, but the organ, as an agent, also produces
an action, as is proper to a brilliant object. For sight is the property of an organ possessing brilliance and
colour. The eyes, therefore, have their proper action as have other parts of the body. Because it is natural to
the eye to be filled with blood-vessels, a woman's eyes, during the period of menstrual flux and
inflammation, will undergo a change, although her husband will not note this since his seed is of the same
nature as that of his wife. The surrounding atmosphere, through which operates the action of sight, and which
surrounds the mirror also, will undergo a change of the same sort that occurred shortly before in the woman's
eyes, and hence the surface of the mirror is likewise affected. And as in the case of a garment, the cleaner it is
the more quickly it is soiled, so the same holds true in the case of the mirror. For anything that is clean will
show quite clearly a stain that it chances to receive, and the cleanest object shows up even the slightest stain.
A bronze mirror, because of its shininess, is especially sensitive to any sort of contact (the movement of the
surrounding air acts upon it like a rubbing or pressing or wiping); on that account, therefore, what is clean
will show up clearly the slightest touch on its surface. It is hard to cleanse smudges off new mirrors because
the stain penetrates deeply and is suffused to all parts; it penetrates deeply because the mirror is not a dense
medium, and is suffused widely because of the smoothness of the object. On the other hand, in the case of old
mirrors, stains do not remain because they do not penetrate deeply, but only smudge the surface.

From this therefore it is plain that stimulatory motion is set up even by slight differences, and that
sense-perception is quick to respond to it; and further that the organ which perceives colour is not only
affected by its object, but also reacts upon it. Further evidence to the same point is afforded by what takes
place in wines, and in the manufacture of unguents. For both oil, when prepared, and wine become rapidly
infected by the odours of the things near them; they not only acquire the odours of the things thrown into or
mixed with them, but also those of the things which are placed, or which grow, near the vessels containing
them.

In order to answer our original question, let us now, therefore, assume one proposition, which is clear from
what precedes, viz. that even when the external object of perception has departed, the impressions it has made
persist, and are themselves objects of perception: and [let us assume], besides, that we are easily deceived
respecting the operations of sense-perception when we are excited by emotions, and different persons
according to their different emotions; for example, the coward when excited by fear, the amorous person by
amorous desire; so that, with but little resemblance to go upon, the former thinks he sees his foes
approaching, the latter, that he sees the object of his desire; and the more deeply one is under the influence of
the emotion, the less similarity is required to give rise to these illusory impressions. Thus too, both in fits of
anger, and also in all states of appetite, all men become easily deceived, and more so the more their emotions
are excited. This is the reason too why persons in the delirium of fever sometimes think they see animals on

ON DREAMS

their chamber walls, an illusion arising from the faint resemblance to animals of the markings thereon when
put together in patterns; and this sometimes corresponds with the emotional states of the sufferers, in such a
way that, if the latter be not very ill, they know well enough that it is an illusion; but if the illness is more
severe they actually move according to the appearances. The cause of these occurrences is that the faculty in
virtue of which the controlling sense judges is not identical with that in virtue of which presentations come
before the mind. A proof of this is, that the sun presents itself as only a foot in diameter, though often
something else gainsays the presentation. Again, when the fingers are crossed, the one object [placed between
them] is felt [by the touch] as two; but yet we deny that it is two; for sight is more authoritative than touch.
Yet, if touch stood alone, we should actually have pronounced the one object to be two. The ground of such
false judgements is that any appearances whatever present themselves, not only when its object stimulates a
sense, but also when the sense by itself alone is stimulated, provided only it be stimulated in the same manner
as it is by the object. For example, to persons sailing past the land seems to move, when it is really the eye
that is being moved by something else [the moving ship.]

From this it is manifest that the stimulatory movements based upon sensory impressions, whether the latter
are derived from external objects or from causes within the body, present themselves not only when persons
are awake, but also then, when this affection which is called sleep has come upon them, with even greater
impressiveness. For by day, while the senses and the intellect are working together, they (i.e. such
movements) are extruded from consciousness or obscured, just as a smaller is beside a larger fire, or as small
beside great pains or pleasures, though, as soon as the latter have ceased, even those which are trifling emerge
into notice. But by night [i.e. in sleep] owing to the inaction of the particular senses, and their powerlessness
to realize themselves, which arises from the reflux of the hot from the exterior parts to the interior, they [i.e.
the above 'movements'] are borne in to the head quarters of sense-perception, and there display themselves as
the disturbance (of waking life) subsides. We must suppose that, like the little eddies which are being ever
formed in rivers, so the sensory movements are each a continuous process, often remaining like what they
were when first started, but often, too, broken into other forms by collisions with obstacles. This [last
mentioned point], moreover, gives the reason why no dreams occur in sleep immediately after meals, or to
sleepers who are extremely young, e.g. to infants. The internal movement in such cases is excessive, owing to
the heat generated from the food. Hence, just as in a liquid, if one vehemently disturbs it, sometimes no
reflected image appears, while at other times one appears, indeed, but utterly distorted, so as to seem quite
unlike its original; while, when once the motion has ceased, the reflected images are clear and plain; in the
same manner during sleep the phantasms, or residuary movements, which are based upon the sensory
impressions, become sometimes quite obliterated by the above described motion when too violent; while at
other times the sights are indeed seen, but confused and weird, and the dreams [which then appear] are
unhealthy, like those of persons who are atrabilious, or feverish, or intoxicated with wine. For all such
affections, being spirituous, cause much commotion and disturbance. In sanguineous animals, in proportion
as the blood becomes calm, and as its purer are separated from its less pure elements, the fact that the
movement, based on impressions derived from each of the organs of sense, is preserved in its integrity,
renders the dreams healthy, causes a [clear] image to present itself, and makes the dreamer think, owing to
the effects borne in from the organ of sight, that he actually sees, and owing to those which come from the
organ of hearing, that he really hears; and so on with those also which proceed from the other sensory organs.
For it is owing to the fact that the movement which reaches the primary organ of sense comes from them, that
one even when awake believes himself to see, or hear, or otherwise perceive; just as it is from a belief that the
organ of sight is being stimulated, though in reality not so stimulated, that we sometimes erroneously declare
ourselves to see, or that, from the fact that touch announces two movements, we think that the one object is
two. For, as a rule, the governing sense affirms the report of each particular sense, unless another particular
sense, more authoritative, makes a contradictory report. In every case an appearance presents itself, but what
appears does not in every case seem real, unless when the deciding faculty is inhibited, or does not move with

ON DREAMS

its proper motion. Moreover, as we said that different men are subject to illusions, each according to the
different emotion present in him, so it is that the sleeper, owing to sleep, and to the movements then going on
in his sensory organs, as well as to the other facts of the sensory process, [is liable to illusion], so that the
dream presentation, though but little like it, appears as some actual given thing. For when one is asleep, in
proportion as most of the blood sinks inwards to its fountain [the heart], the internal [sensory] movements,
some potential, others actual accompany it inwards. They are so related [in general] that, if anything move
the blood, some one sensory movement will emerge from it, while if this perishes another will take its place;
while to one another also they are related in the same way as the artificial frogs in water which severally rise
[in fixed succesion] to the surface in the order in which the salt [which keeps them down] becomes dissolved.
The residuary movements are like these: they are within the soul potentially, but actualize themselves only
when the impediment to their doing so has been relaxed; and according as they are thus set free, they begin to
move in the blood which remains in the sensory organs, and which is now but scanty, while they possess
verisimilitude after the manner of cloud-shapes, which in their rapid metamorphoses one compares now to
human beings and a moment afterwards to centaurs. Each of them is however, as has been said, the remnant
of a sensory impression taken when sense was actualizing itself; and when this, the true impression, has
departed, its remnant is still immanent, and it is correct to say of it, that though not actually Koriskos, it is
like Koriskos. For when the person was actually perceiving, his controlling and judging sensory faculty did
not call it Koriskos, but, prompted by this [impression], called the genuine person yonder Koriskos.
Accordingly, this sensory impulse, which, when actually perceiving, it [the controlling faculty] describes
(unless completely inhibited by the blood), it now [in dreams] when quasi-perceiving, receives from the
movements persisting in the sense-organs, and mistakes it-an impulse that is merely like the true [objective]
impression-for the true impression itself, while the effect of sleep is so great that it causes this mistake to
pass unnoticed. Accordingly, just as if a finger be inserted beneath the eyeball without being observed, one
object will not only present two visual images, but will create an opinion of its being two objects; while if it
[the finger] be observed, the presentation will be the same, but the same opinion will not be formed of it;
exactly so it is in states of sleep: if the sleeper perceives that he is asleep, and is conscious of the sleeping
state during which the perception comes before his mind, it presents itself still, but something within him
speaks to this effect: 'the image of Koriskos presents itself, but the real Koriskos is not present'; for often,
when one is asleep, there is something in consciousness which declares that what then presents itself is but a
dream. If, however, he is not aware of being asleep, there is nothing which will contradict the testimony of
the bare presentation.

That what we here urge is true, i.e. that there are such presentative movements in the sensory organs, any one
may convince himself, if he attends to and tries to remember the affections we experience when sinking into
slumber or when being awakened. He will sometimes, in the moment of awakening, surprise the images
which present themselves to him in sleep, and find that they are really but movements lurking in the organs of
sense. And indeed some very young persons, if it is dark, though looking with wide open eyes, see multitudes
of phantom figures moving before them, so that they often cover up their heads in terror.

From all this, then, the conclusion to be drawn is, that the dream is a sort of presentation, and, more
particularly, one which occurs in sleep; since the phantoms just mentioned are not dreams, nor is any other a
dream which presents itself when the sense-perceptions are in a state of freedom. Nor is every presentation
which occurs in sleep necessarily a dream. For in the first place, some persons [when asleep] actually, in a
certain way, perceive sounds, light, savour, and contact; feebly, however, and, as it were, remotely. For there
have been cases in which persons while asleep, but with the eyes partly open, saw faintly in their sleep (as
they supposed) the light of a lamp, and afterwards, on being awakened, straightway recognized it as the
actual light of a real lamp; while, in other cases, persons who faintly heard the crowing of cocks or the
barking of dogs identified these clearly with the real sounds as soon as they awoke. Some persons, too, return
answers to questions put to them in sleep. For it is quite possible that, of waking or sleeping, while the one is
present in the ordinary sense, the other also should be present in a certain way. But none of these occurrences
should be called a dream. Nor should the true thoughts, as distinct from the mere presentations, which occur

ON DREAMS

in sleep [be called dreams]. The dream proper is a presentation based on the movement of sense impressions,
when such presentation occurs during sleep, taking sleep in the strict sense of the term.

There are cases of persons who in their whole lives have never had a dream, while others dream when
considerably advanced in years, having never dreamed before. The cause of their not having dreams appears
somewhat like that which operates in the case of infants, and [that which operates] immediately after meals. It
is intelligible enough that no dream-presentation should occur to persons whose natural constitution is such
that in them copious evaporation is borne upwards, which, when borne back downwards, causes a large
quantity of motion. But it is not surprising that, as age advances, a dream should at length appear to them.
Indeed, it is inevitable that, as a change is wrought in them in proportion to age or emotional experience, this
reversal [from non-dreaming to dreaming] should occur also.

THE END

ON THE GAIT OF ANIMALS

by Aristotle

ON THE GAIT OF ANIMALS

Table of Contents

ON THE GAIT OF ANIMALS 1

by Aristotle 1

_1 1

2 2

3. 2

A 2

_5 3

6 4

1_ 4

1 5

_9 6

JO 7

11 7

J2 8

13 9

14 9

15 9

16 10

17 10

18 11

19 11

ON THE GAIT OF ANIMALS

by Aristotle

translated by A. S. L. Farquharson

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II
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19

WE have now to consider the parts which are useful to animals for movement in place (locomotion); first,
why each part is such as it is and to what end they possess them; and second, the differences between these
parts both in one and the same creature, and again by comparison of the parts of creatures of different species
with one another. First then let us lay down how many questions we have to consider.

The first is what are the fewest points of motion necessary to animal progression, the second why
sanguineous animals have four points and not more, but bloodless animals more than four, and generally why
some animals are footless, others bipeds, others quadrupeds, others polypods, and why all have an even
number of feet, if they have feet at all; why in fine the points on which progression depends are even in
number.

Next, why are man and bird bipeds, but fish footless; and why do man and bird, though both bipeds, have an
opposite curvature of the legs. For man bends his legs convexly, a bird has his bent concavely; again, man
bends his arms and legs in opposite directions, for he has his arms bent convexly, but his legs concavely. And

ON THE GAIT OF ANIMALS 1

ON THE GAIT OF ANIMALS

a viviparous quadruped bends his limbs in opposite directions to a man's, and in opposite directions to one
another; for he has his forelegs bent convexly, his hind legs concavely. Again, quadrupeds which are not
viviparous but oviparous have a peculiar curvature of the limbs laterally away from the body. Again, why do
quadrupeds move their legs criss-cross?

We have to examine the reasons for all these facts, and others cognate to them; that the facts are such is clear
from our Natural History, we have now to ask reasons for the facts.

At the beginning of the inquiry we must postulate the principles we are accustomed constantly to use for our
scientific investigation of nature, that is we must take for granted principles of this universal character which
appear in all Nature's work. Of these one is that Nature creates nothing without a purpose, but always the best
possible in each kind of living creature by reference to its essential constitution. Accordingly if one way is
better than another that is the way of Nature. Next we must take for granted the different species of
dimensions which inhere in various things; of these there are three pairs of two each, superior and inferior,
before and behind, to the right and to the left. Further we must assume that the originals of movements in
place are thrusts and pulls. (These are the essential place-movements, it is only accidentally that what is
carried by another is moved; it is not thought to move itself, but to be moved by something else.)

After these preliminaries, we go on to the next questions in order.

Now of animals which change their position some move with the whole body at once, for example jumping
animals, others move one part first and then the other, for example walking (and running) animals. In both
these changes the moving creature always changes its position by pressing against what lies below it.
Accordingly if what is below gives way too quickly for that which is moving upon it to lean against it, or if it
affords no resistance at all to what is moving, the latter can of itself effect no movement upon it. For an
animal which jumps makes its jump both by leaning against its own upper part and also against what is
beneath its feet; for at the joints the parts do in a sense lean upon one another, and in general that which
pushes down leans upon what is pushed down. That is why athletes jump further with weights in their hands
than without, and runners run faster if they swing their arms; there is in extending the arms a kind of leaning
against the hands and wrists. In all cases then that which moves makes its change of position by the use of at
least two parts of the body; one part so to speak squeezes, the other is squeezed; for the part that is still is
squeezed as it has to carry the weight, the part that is lifted strains against that which carries the weight. It
follows then that nothing without parts can move itself in this way, for it has not in it the distinction of the
part which is passive and that which is active.

Again, the boundaries by which living beings are naturally determined are six in number, superior and
inferior, before and behind, right and left. Of these all living beings have a superior and an inferior part; for
superior and inferior is in plants too, not only in animals. And this distinction is one of function, not merely
of position relatively to our earth and the sky above our heads. The superior is that from which flows in each
kind the distribution of nutriment and the process of growth; the inferior is that to which the process flows
and in which it ends. One is a starting-point, the other an end, and the starting-point is the superior. And yet
it might be thought that in the case of plants at least the inferior is rather the appropriate starting-point, for in
them the superior and inferior are in position other than in animals. Still they are similarly situated from the
point of view of function, though not in their position relatively to the universe. The roots are the superior

ON THE GAIT OF ANIMALS

part of a plant, for from them the nutriment is distributed to the growing members, and a plant takes it with its
roots as an animal does with its mouth.

Things that are not only alive but are animals have both a front and a back, because they all have sense, and
front and back are distinguished by reference to sense. The front is the part in which sense is innate, and
whence each thing gets its sensations, the opposite parts are the back.

All animals which partake not only in sense, but are able of themselves to make a change of place, have a
further distinction of left and right besides those already enumerated; like the former these are distinctions of
function and not of position. The right is that from which change of position naturally begins, the opposite
which naturally depends upon this is the left.

This distinction (of right and left) is more articulate and detailed in some than in others. For animals which
make the aforesaid change (of place) by the help of organized parts (I mean feet for example, or wings or
similar organs) have the left and right distinguished in greater detail, while those which are not differentiated
into such parts, but make the differentiation in the body itself and so progress, like some footless animals (for
example snakes and caterpillars after their kind, and besides what men call earth-worms), all these have the
distinction spoken of, although it is not made so manifest to us. That the beginning of movement is on the
right is indicated by the fact that all men carry burdens on the left shoulder; in this way they set free the side
which initiates movement and enable the side which bears the weight to be moved. And so men hop easier on
the left leg; for the nature of the right is to initiate movement, that of the left to be moved. The burden then
must rest on the side which is to be moved, not on that which is going to cause movement, and if it be set on
the moving side, which is the original of movement, it will either not be moved at all or with more labour.
Another indication that the right is the source of movement is the way we put our feet forward; all men lead
off with the left, and after standing still prefer to put the left foot forward, unless something happens to
prevent it. The reason is that their movement comes from the leg they step off, not from the one put forward.
Again, men guard themselves with their right. And this is the reason why the right is the same in all, for that
from which motion begins is the same for all, and has its natural position in the same place, and for this
reason the spiral-shaped Testaceans have their shells on the right, for they do not move in the direction of the
spire, but all go forward in the direction opposite to the spire. Examples are the murex and the ceryx. As all
animals then start movement from the right, and the right moves in the same direction as the whole, it is
necessary for all to be alike right-handed. And man has the left limbs detached more than any other animal
because he is natural in a higher degree than the other animals; now the right is naturally both better than the
left and separate from it, and so in man the right is more especially the right, more dextrous that is, than in
other animals. The right then being differentiated it is only reasonable that in man the left should be most
movable, and most detached. In man, too, the other starting-points are found most naturally and clearly
distinct, the superior part that is and the front.

Animals which, like men and birds, have the superior part distinguished from the front are two-footed
(biped). In them, of the four points of motion, two are wings in the one, hands and arms in the other. Animals
which have the superior and the front parts identically situated are four-footed, many-footed, or footless
(quadruped, polypod, limbless). I use the term foot for a member employed for movement in place connected
with a point on the ground, for the feet appear to have got their name from the ground under our feet.

Some animals, too, have the front and back parts identically situated, for example, Cephalopods (molluscs)
and spiral-shaped Testaceans, and these we have discussed elsewhere in another connexion.

Now there is in place a superior, an intermediate, and an inferior; in respect to place bipeds have their

ON THE GAIT OF ANIMALS

superior part corresponding to the part of the universe; quadrupeds, polypods, and footless animals to the
intermediate part, and plants to the inferior. The reason is that these have no power of locomotion, and the
superior part is determined relatively to the nutriment, and their nutriment is from the earth. Quadrupeds,
polypods, and footless animals again have their superior part corresponding to the intermediate, because they
are not erect. Bipeds have theirs corresponding to the superior part of the universe because they are erect, and
of bipeds, man par excellence; for man is the most natural of bipeds. And it is reasonable for the starting
points to be in these parts; for the starting-point is honourable, and the superior is more honourable than the
inferior, the front than the back, and the right than the left. Or we may reverse the argument and say quite
well that these parts are more honourable than their opposites just because the starting-points are in them.

The above discussion has made it clear that the original of movement is in the parts on the right. Now every
continuous whole, one part of which is moved while the other remains at rest must, in order to be able to
move as a whole while one part stands still, have in the place where both parts have opposed movements
some common part which connects the moving parts with one another. Further in this common part the
original of the motion (and similarly of the absence of motion) of each of the parts must lie.

Clearly then if any of the opposite pairs of parts (right and left, that is, superior and inferior, before and
behind) have a movement of their own, each of them has for common original of its movements the juncture
of the parts in question.

Now before and behind are not distinctions relatively to that which sets up its own motion, because in nature
nothing has a movement backwards, nor has a moving animal any division whereby it may make a change of
position towards its front or back; but right and left, superior and inferior are so distinguished. Accordingly,
all animals which progress by the use of distinct members have these members distinguished not by the
differences of before and behind, but only of the remaining two pairs; the prior difference dividing these
members into right and left (a difference which must appear as soon as you have division into two), and the
other difference appearing of necessity where there is division into four.

Since then these two pairs, the superior and inferior and the right and left, are linked to one another by the
same common original (by which I mean that which controls their movement), and further, everything which
is intended to make a movement in each such part properly must have the original cause of all the said
movements arranged in a certain definite position relatively to the distances from it of the originals of the
movements of the individual members (and these centres of the individual parts are in pairs arranged
coordinately or diagonally, and the common centre is the original from which the animal's movements of
right and left, and similarly of superior and inferior, start); each animal must have this original at a point
where it is equally or nearly equally related to each of the centres in the four parts described.

It is clear then how locomotion belongs to those animals only which make their changes of place by means of
two or four points in their structure, or to such animals par excellence. Moreover, since this property belongs
almost peculiarly to Sanguineous animals, we see that no Sanguineous animal can progress at more points
than four, and that if it is the nature of anything so to progress at four points it must of necessity be
Sanguineous.

What we observe in the animal world is in agreement with the above account. For no Sanguineous animal if it
be divided into more parts can live for any appreciable length of time, nor can it enjoy the power of
locomotion which it possessed while it was a continuous and undivided whole. But some bloodless animals

ON THE GAIT OF ANIMALS

and polypods can live a long time, if divided, in each of the severed parts, and can move in the same way as
before they were dismembered. Examples are what is termed the centipede and other insects that are long in
shape, for even the hinder portion of all these goes on progressing in the same direction as before when they
are cut in two.

The explanation of their living when thus divided is that each of them is constructed like a continuous body
of many separate living beings. It is plain, too, from what was said above why they are like this. Animals
constructed most naturally are made to move at two or four points, and even limbless Sanguinea are no
exception. They too move by dint of four points, whereby they achieve progression. They go forward by
means of two flexions. For in each of their flexions there is a right and a left, both before and behind in their
flat surface, in the part towards the head a right and a left front point, and in the part towards the tail the two
hinder points. They look as if they moved at two points only, where they touch before and behind, but that is
only because they are narrow in breadth. Even, in them the right is the sovereign part, and there is an alternate
correspondence behind, exactly as in quadrupeds. The reason of their flexions is their great length, for just as
tall men walk with their spines bellied (undulated) forward, and when their right shoulder is leading in a
forward direction their left hip rather inclined backwards, so that their middle becomes hollow and bellied
(undulated), so we ought to conceive snakes as moving in concave curves (undulations) upon the ground.
And this is evidence that they move themselves like the quadrupeds, for they make the concave in its turn
convex and the convex concave. When in its turn the left of the forward parts is leading, the concavity is in its
turn reversed, for the right becomes the inner. (Let the right front point be A, the left B, the right hind C, the
left D.)

Among land animals this is the character of the movement of snakes, and among water animals of eels, and
conger-eels and also lampreys, in fact of all that have their form snakelike. However, some marine animals
of this shape have no fin, lampreys for example, but put the sea to the same use as snakes do both land and
water (for snakes swim precisely as they move on the ground). Others have two fins only, for example
conger-eels and eels and a kind of cestreus which breeds in the lake of Siphae. On this account too those that
are accustomed to live on land, for example all the eels, move with fewer flexions in a fluid than on land,
while the kind of cestreus which has two fins, by its flexion in a fluid makes up the remaining points.

The reason why snakes are limbless is first that nature makes nothing without purpose, but always regards
what is the best possible for each individual, preserving the peculiar essence of each and its intended
character, and secondly the principle we laid down above that no Sanguineous creature can move itself at
more than four points. Granting this it is evident that Sanguineous animals like snakes, whose length is out of
proportion to the rest of their dimensions, cannot possibly have limbs; for they cannot have more than four
(or they would be bloodless), and if they had two or four they would be practically stationary; so slow and
unprofitable would their movement necessarily be.

But every limbed animal has necessarily an even number of such limbs. For those which only jump and so
move from place to place do not need limbs for this movement at least, but those which not only jump but
also need to walk, finding that movement not sufficient for their purposes, evidently either are better able to
progress with even limbs or cannot otherwise progress at all every animal which has limbs must have an even
us for as this kind of movement is effected by part of the body at a time, and not by the whole at once as in
the movement of leaping, some of the limbs must in turn remain at rest, and others be moved, and the animal
must act in each of these cases with opposite limbs, shifting the weight from the limbs that are being moved
to those at rest. And so nothing can walk on three limbs or on one; in the latter case it has no support at all on
which to rest the body's weight, in the former only in respect of one pair of opposites, and so it must
necessarily fall in endeavouring so to move.

ON THE GAIT OF ANIMALS

Polypods however, like the Centipede, can indeed make progress on an odd number of limbs, as may be seen
by the experiment of wounding one of their limbs; for then the mutilation of one row of limbs is corrected by
the number of limbs which remain on either side. Such mutilated creatures, however, drag the wounded limb
after them with the remainder, and do not properly speaking walk. Moreover, it is plain that they, too, would
make the change of place better if they had an even number, in fact if none were missing and they had the
limbs which correspond to one another. In this way they could equalize their own weight, and not oscillate to
one side, if they had corresponding supports instead of one section of the opposite sides being unoccupied by
a limb. A walking creature advances from each of its members alternately, for in this way it recovers the
same figure that it had at first.

The fact that all animals have an even number of feet, and the reasons for the fact have been set forth. What
follows will explain that if there were no point at rest flexion and straightening would be impossible. Flexion
is a change from a right line to an arc or an angle, straightening a change from either of these to a right line.
Now in all such changes the flexion or the straightening must be relative to one point. Moreover, without
flexion there could not be walking or swimming or flying. For since limbed creatures stand and take their
weight alternately on one or other of the opposite legs, if one be thrust forward the other of necessity must be
bent. For the opposite limbs are naturally of equal length, and the one which is under the weight must be a
kind of perpendicular at right angles to the ground.

When then one leg is advanced it becomes the hypotenuse of a right-angled triangle. Its square then is equal
to the square on the other side together with the square on the base. As the legs then are equal, the one at rest
must bend either at the knee or, if there were any kneeless animal which walked, at some other articulation.
The following experiment exhibits the fact. If a man were to walk parallel to a wall in sunshine, the line
described (by the shadow of his head> would be not straight but zigzag, becoming lower as he bends, and
higher when he stands and lifts himself up.

It is, indeed, possible to move oneself even if the leg be not bent, in the way in which children crawl. This
was the old though erroneous account of the movement of elephants. But these kinds of movements involve a
flexion in the shoulders or in the hips. Nothing at any rate could walk upright continuously and securely
without flexions at the knee, but would have to move like men in the wrestling schools who crawl forward
through the sand on their knees. For the upper part of the upright creature is long so that its leg has to be
correspondingly long; in consequence there must be flexion. For since a stationary position is perpendicular,
if that which moves cannot bend it will either fall forward as the right angle becomes acute or will not be able
to progress. For if one leg is at right angles to the ground and the other is advanced, the latter will be at once
equal and greater. For it will be equal to the stationary leg and also equivalent to the hypotenuse of a
right-angled triangle. That which goes forward therefore must bend, and while bending one, extend the other
leg simultaneously, so as to incline forward and make a stride and still remain above the perpendicular; for
the legs form an isosceles triangle, and the head sinks lower when it is perpendicularly above the base on
which it stands.

Of limbless animals, some progress by undulations (and this happens in two ways, either they undulate on the
ground, like snakes, or up and down, like caterpillars), and undulation is a flexion; others by a telescopic
action, like what are called earthworms and leeches. These go forward, first one part leading and then
drawing the whole of the rest of the body up to this, and so they change from place to place. It is plain too
that if the two curves were not greater than the one line which subtends them undulating animals could not
move themselves; when the flexure is extended they would not have moved forward at all if the flexure or arc
were equal to the chord subtended; as it is, it reaches further when it is straightened out, and then this part
stays still and it draws up what is left behind.

ON THE GAIT OF ANIMALS

In all the changes described that which moves now extends itself in a straight line to progress, and now is
hooped; it straightens itself in its leading part, and is hooped in what follows behind. Even jumping animals
all make a flexion in the part of the body which is underneath, and after this fashion make their leaps. So too
flying and swimming things progress, the one straightening and bending their wings to fly, the other their fins
to swim. Of the latter some have four fins, others which are rather long, for example eels, have only two.
These swim by substituting a flexion of the rest of their body for the (missing) pair of fins to complete the
movement, as we have said before. Flat fish use two fins, and the flat of their body as a substitute for the
absent pair of fins. Quite flat fish, like the Ray, produce their swimming movement with the actual fins and
with the two extremes or semicircles of their body, bending and straightening themselves alternately.

A difficulty might perhaps be raised about birds. How, it may be said, can they, either when they fly or when
they walk, be said to move at four points? Now we did not say that all Sanguinea move at four points, but
merely at not more than four. Moreover, they cannot as a fact fly if their legs be removed, nor walk without
their wings. Even a man does not walk without moving his shoulders. Everything indeed, as we have said,
makes a change of place by flexion and straightening, for all things progress by pressing upon what being
beneath them up to a point gives way as it were gradually; accordingly, even if there be no flexion in another
member, there must be at least in the point whence motion begins, is in feathered (flying) insects at the base
of the 'scale-wing', in birds at the base of the wing, in others at the base of the corresponding member, the
fins, for instance, in fish. In others, for example snakes, the flexion begins in the joints of the body.

In winged creatures the tail serves, like a ship's rudder, to keep the flying thing in its course. The tail then
must like other limbs be able to bend at the point of attachment. And so flying insects, and birds
(Schizoptera) whose tails are ill-adapted for the use in question, for example peacocks, and domestic cocks,
and generally birds that hardly fly, cannot steer a straight course. Flying insects have absolutely no tail, and
so drift along like a rudderless vessel, and beat against anything they happen upon; and this applies equally to
sharded insects, like the scarab-beetle and the chafer, and to unsharded, like bees and wasps. Further, birds
that are not made for flight have a tail that is of no use; for instance the purple coot and the heron and all
water-fowl. These fly stretching out their feet as a substitute for a tail, and use their legs instead of a tail to
direct their flight. The flight of insects is slow and frail because the character of their feathery wings is not
proportionate to the bulk of their body; this is heavy, their wings small and frail, and so the flight they use is
like a cargo boat attempting to make its voyage with oars; now the frailty both of the actual wings and of the
outgrowths upon them contributes in a measure to the flight described. Among birds, the peacock's tail is at
one time useless because of its size, at another because it is shed. But birds are in general at the opposite pole
to flying insects as regards their feathers, but especially the swiftest flyers among them. (These are the birds
with curved talons, for swiftness of wing is useful to their mode of life.) The rest of their bodily structure is in
harmony with their peculiar movement, the small head, the slight neck, the strong and acute breastbone (acute
like the prow of a clipper-built vessel, so as to be well-girt, and strong by dint of its mass of flesh), in order
to be able to push away the air that beats against it, and that easily and without exhaustion. The
hind-quarters, too, are light and taper again, in order to conform to the movement of the front and not by
their breadth to suck the air.

So much then for these questions. But why an animal that is to stand erect must necessarily be not only a
biped, but must also have the superior parts of the body lighter, and those that lie under these heavier, is
plain. Only if situated like this could it possibly carry itself easily. And so man, the only erect animal, has
legs longer and stouter relatively to the upper parts of his body than any other animal with legs. What we
observe in children also is evidence of this. Children cannot walk erect because they are always dwarf-like,

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ON THE GAIT OF ANIMALS

the upper parts of their bodies being longer and stouter than the lower. With advancing years the lower
increase disproportionately, until the children get their appropriate size, and then and not till then they
succeed in walking erect. Birds are hunchbacked yet stand on two legs because their weight is set back, after
the principle of horses fashioned in bronze with their forelegs prancing. But their being bipeds and able to
stand is above all due to their having the hip-bone shaped like a thigh, and so large that it looks as if they had
two thighs, one in the leg before the knee-joint, the other joining his part to the fundament. Really this is not
a thigh but a hip, and if it were not so large the bird could not be a biped. As in a man or a quadruped, the
thigh and the rest of the leg would be attached immediately to quite a small hip; consequently the whole body
would be tilted forward. As it is, however, the hip is long and extends right along to the middle of the belly,
so that the legs are attached at that point and carry as supports the whole frame. It is also evident from these
considerations that a bird cannot possibly be erect in the sense in which man is. For as it holds its body now
the wings are naturally useful to it, but if it were erect they would be as useless as the wings of Cupids we see
in pictures. It must have been clear as soon as we spoke that the form of no human nor any similar being
permits of wings; not only because it would, though Sanguineous, be moved at more than four points, but
also because to have wings would be useless to it when moving naturally. And Nature makes nothing
contrary to her own nature.

We have stated above that without flexion in the legs or shoulders and hips no Sanguineous animal with feet
could progress, and that flexion is impossible except some point be at rest, and that men and birds, both
bipeds, bend their legs in opposite directions, and further that quadrupeds bend their in opposite directions,
and each pair in the opposite way to a man's limbs. For men bend their arms backwards, their legs forwards;
quadrupeds their forelegs forwards, their back legs backwards, and in like manner also birds bend theirs. The
reason is that Nature's workmanship is never purposeless, as we said above, but everything for the best
possible in the circumstances. Inasmuch, therefore, as all creatures which naturally have the power of
changing position by the use of limbs, must have one leg stationary with the weight of the body on it, and
when they move forward the leg which has the leading position must be unencumbered, and the progression
continuing the weight must shift and be taken off on this leading leg, it is evidently necessary for the back leg
from being bent to become straight again, while the point of movement of the leg thrust forward and its lower
part remain still. And so the legs must be jointed. And it is possible for this to take place and at the same time
for the animal to go forward, if the leading leg has its articulation forwards, impossible if it be backwards.
For, if it be forwards, the stretching out of the leg will be while the body is going forwards, but, if the other
way, while it is going backwards. And again, if the flexion were backwards, the placing of the foot would be
made by two movements and those contrary to one another, one, that is, backwards and one forwards; for in
the bending together of the limb the lower end of the thigh would go backwards, and the shin would move the
foot forwards away from the flexion; whereas, with the flexion forwards, the progression described will be
performed not with contrary motions, but with one forward motion.

Now man, being a biped and making his change of position in the natural way with his two legs, bends them
forward for the reasons set forth, but his arms bend backwards reasonably enough. If they bent the opposite
way they would be useless for the work of the hands, and for taking food. But quadrupeds which are also
viviparous necessarily bend their front legs forwards. For these lead off first when they move, and are also in
the forepart of their body. The reason that they bend forward is the same as in the case of man, for in this
respect they are like mankind. And so quadrupeds as well as men bend these legs forward in the manner
described. Moreover, if the flexion is like this, they are enabled to lift their feet high; if they bent them in the
opposite way they would only lift them a little way from the ground, because the whole thigh and the joint
from which the shin-bone springs would lie under the belly as the beast moved forward. If, however, the
flexion of the hind legs were forwards the lifting of these feet would be similar to that of the forefeet (for the
hind legs, too, would in this case have only a little room for their lifting inasmuch as both the thigh and the

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ON THE GAIT OF ANIMALS

knee-joint would fall under the position of the belly); but the flexion being backwards, as in fact it is, nothing
comes in the way of their progression with this mode of moving the feet. Moreover, it is necessary or at least
better for their legs to bend thus when they are suckling their young, with a view to such ministrations. If the
flexion were inwards it would be difficult to keep their young under them and to shelter them.

Now there are four modes of flexion if we take the combinations in pairs. Fore and hind may bend either both
backwards, as the figures marked A, or in the opposite way both forwards, as in B, or in converse ways and
not in the same direction, as in C where the fore bend forwards and the hind bend backwards, or as in D, the
opposite way to C, where the convexities are turned towards one another and the concavities outwards. Now
no biped or quadruped bends his limbs like the figures A or B, but the quadrupeds like C, and like D only the
elephant among quadrupeds and man if you consider his arms as well as his legs. For he bends his arms
concavely and his legs convexly.

In man, too, the flexions of the limbs are always alternately opposite, for example the elbow bends back, but
the wrist of the hand forwards, and again the shoulder forwards. In like fashion, too, in the case of the legs,
the hip backwards, the knee forwards, the ankle in the opposite way backwards. And plainly the lower limbs
are opposed in this respect to the upper, because the first joints are opposites, the shoulder bending forwards,
the hip backwards; wherefore also the ankle bends backwards, and the wrist of the hand forwards.

This is the way then the limbs bend, and for the reasons given. But the hind limbs move criss-cross with the
fore limbs; after the off fore they move the near hind, then the near fore, and then the off hind. The reason is
that (a) if they moved the forelegs together and first, the animal would be wrenched, and the progression
would be a stumbling forwards with the hind parts as it were dragged after. Again, that would not be walking
but jumping, and it is hard to make a continuous change of place, jumping all the time. Here is evidence of
what I say; even as it is, all horses that move in this way soon begin to refuse, for example the horses in a
religious procession. For these reasons the fore limbs and the hind limbs move in this separate way. Again,
(b) if they moved both the right legs first the weight would be outside the supporting limbs and they would
fall. If then it is necessary to move in one or other of these ways or criss-cross fashion, and neither of these
two is satisfactory, they must move criss-cross; for moving in the way we have said they cannot possibly
experience either of these untoward results. And this is why horses and such-like animals stand still with
their legs put forward criss-cross, not with the right or the left put forward together at once. In the same
fashion animals with more than four legs make their movements; if you take two consecutive pairs of legs the
hind move criss-cross with the forelegs; you can see this if you watch them moving slowly. Even crabs move
in this way, and they are polypods. They, too, always move criss-cross in whichever direction they are
making progress. For in direction this animal has a movement all its own; it is the only animal that moves not
forwards, but obliquely. Yet since forwards is a distinction relative to the line of vision, Nature has made its
eyes able to conform to its limbs, for its eyes can move themselves obliquely, and therefore after a fashion
crabs are no exception but in this sense move forwards.

Birds bend their legs in the same way as quadrupeds. For their natural construction is broadly speaking nearly
the same. That is, in birds the wings are a substitute for the forelegs; and so they are bent in the same way as
the forelegs of a quadruped, since when they move to progress the natural beginning of change is from the
wings (as in quadrupeds from the forelegs). Flight in fact is their appropriate movement. And so if the wings
be cut off a bird can neither stand still nor go forwards.

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ON THE GAIT OF ANIMALS

Again, the bird though a biped is not erect, and has the forward parts of the body lighter than the hind, and so
it is necessary (or at least preferable for the standing posture) to have the thigh so placed below the body as it
actually is, I mean growing towards the back. If then it must have this situation the flexion of the leg must be
backwards, as in the hind legs of quadrupeds. The reasons are the same as those given in the case of
viviparous quadrupeds.

If now we survey generally birds and winged insects, and animals which swim in a watery medium, all I
mean that make their progress in water by dint of organs of movement, it is not difficult to see that it is better
to have the attachment of the parts in question oblique to the frame, exactly as in fact we see it to be both in
birds and insects. And this same arrangement obtains also among fishes. Among birds the wings are attached
obliquely; so are the fins in water animals, and the feather-like wings of insects. In this way they divide the
air or water most quickly and with most force and so effect their movement. For the hinder parts in this way
would follow forwards as they are carried along in the yielding medium, fish in the water, birds in the air.

Of oviparous quadrupeds all those that live in holes, like crocodiles, lizards, spotted lizards, freshwater
tortoises, and turtles, have their legs attached obliquely as their whole body sprawls over the ground, and
bend them obliquely. The reason is that this is useful for ease in creeping into holes, and for sitting upon their
eggs and guarding them. And as they are splayed outwards they must of necessity tuck in their thighs and put
them under them in order to achieve the lifting of the whole body. In view of this they cannot bend them
otherwise than outwards.

We have already stated the fact that non-sanguineous animals with limbs are polypods and none of them
quadrupeds. And the reason why their legs, except the extreme pairs, were necessarily attached obliquely and
had their flexions upwards, and the legs themselves were somewhat turned under (bandy-shape) and
backwards is plain. In all such creatures the intermediate legs both lead and follow. If then they lay under
them, they must have had their flexion both forwards and backwards; on account of leading, forwards; and on
account of following, backwards. Now since they have to do both, for this reason their limbs are turned under
and bent obliquely, except the two extreme pairs. (These two are more natural in their movement, the front
leading and the back following.) Another reason for this kind of flexion is the number of their legs; arranged
in this way they would interfere less with one another in progression and not knock together. But the reason
that they are bandy is that all of them or most of them live in holes, for creatures living so cannot possibly be
high above the ground.

But crabs are in nature the oddest of all polypods; they do not progress forwards except in the sense explained
above, they are the only animals which have more than one pair of leading limbs. The explanation of this is
the hardness of their limbs, and the fact that they use them not for swimming but for walking; they always
keep on the ground. However, the flexion of the limbs of all polypods is oblique, like that of the quadrupeds
which live in holes-for example lizards and crocodiles and most of the oviparous quadrupeds. And the
explanation is that some of them in their breeding periods, and some all their life, live in holes.

Now the rest have bandy legs because they are soft-skinned, but the crayfish is hard-skinned and its limbs
are for swimming and not for walking (and so are not bandy). Crabs, too, have their limbs bent obliquely, but
not bandy like oviparous quadrupeds and non-sanguineous polypods, because their limbs have a hard and
shell-like skin, although they don't swim but live in holes; they live in fact on the ground. Moreover, their
shape is like a disk, as compared with the crayfish which is elongated, and they haven't a tail like the crayfish;
a tail is useful to the crayfish for swimming, but the crab is not a swimming creature. Further, it alone has its

16 10

ON THE GAIT OF ANIMALS

side equivalent to a hinder part, because it has many leading feet. The explanation of this is that its flexions
are not forward nor its legs turned in under (bandy). We have given above the reason why its legs are not
turned in under, that is the hardness and shell-like character of its integument.

For these reasons then it must lead off with more than one limb, and move obliquely; obliquely, because the
flexion is oblique; and with more than one limb, because otherwise the limbs that were still would have got in
the way of those that were moving.

Fishes of the flat kind swim with their heads twisted, as one-eyed men walk; they have their natural shape
distorted. Web-footed birds swim with their feet; because they breath the air and have lungs they are bipeds,
but because they have their home in the water they are webbed; by this arrangement their feet serve them
instead of fins. They have their legs too, not like the rest of birds in the centre of their body, but rather set
back. Their legs are short, and being set back are serviceable for swimming. The reason for their having short
legs is that nature has added to their feet by subtracting from the length of their limbs; instead of length she
gives stoutness to the legs and breadth to the feet. Broad feet are more useful than long for pushing away the
water when they are swimming.

There is reason, too, for winged creatures having feet, but fish none. The former have their home in the dry
medium, and cannot remain always in mid air; they must therefore have feet. Fish on the contrary live in the
wet medium, and take in water, not air. Fins are useful for swimming, but feet not. And if they had both they
would be non-sanguineous. There is a broad similarity between birds and fishes in the organs of locomotion.
Birds have their wings on the superior part, similarly fish have two pectoral fins; again, birds have legs on
their under parts and near the wings; similarly, most fish have two fins on the under parts and near the
pectorals. Birds, too, have a tail and fish a tail-fin.

A difficulty may be suggested as to the movements of molluscs, that is, as to where that movement
originates; for they have no distinction of left and right. Now observation shows them moving. We must, I
think, treat all this class as mutilated, and as moving in the way in which limbed creatures do when one cuts
off their legs, or as analogous with the seal and the bat. Both the latter are quadrupeds but misshapen. Now
molluscs do move, but move in a manner contrary to nature. They are not moving things, but are moving if as
sedentary creatures they are compared with zoophytes, and sedentary if classed with progressing animals.

As to right and left, crabs, too, show the distinction poorly, still they do show it. You can see it in the claw;
the right claw is larger and stronger, as though the right and left sides were trying to get distinguished.

The structure of animals, both in their other parts, and especially in those which concern progression and any
movement in place, is as we have now described. It remains, after determining these questions, to investigate
the problems of Life and Death.

-THE END-

18 11

ON GENERATION AND CORRUPTION

by Aristotle

ON GENERATION AND CORRUPTION

Table of Contents

ON GENERATION AND CORRUPTION. 1

by Aristotle 1

Book 1 1

_1 1

2 3

_2 6

A 9

_5 10

_6 13

1 15

_8 16

_9 19

JO 20

Book II . 22

_1 22

2 23

3. 24

A 25

_5 26

6 28

1_ 29

1 30

_9 31

10 32

11 34

ON GENERATION AND CORRUPTION

by Aristotle

translated by H. H. Joachim

« Book I
1
2
3
4
5
6
7
8
9
10

• Book II

Book I

OUR next task is to study coming-to-be and passing-away. We are to distinguish the causes, and to state the
definitions, of these processes considered in general-as changes predicable uniformly of all the things that
come-to-be and pass-away by nature. Further, we are to study growth and 'alteration'. We must inquire what
each of them is; and whether 'alteration' is to be identified with coming-to-be, or whether to these different
names there correspond two separate processes with distinct natures.

On this question, indeed, the early philosophers are divided. Some of them assert that the so-called
'unqualified coming-to-be' is 'alteration', while others maintain that 'alteration' and coming-to-be are

ON GENERATION AND CORRUPTION 1

ON GENERATION AND CORRUPTION

distinct. For those who say that the universe is one something (i.e. those who generate all things out of one
thing) are bound to assert that coming-to-be is 'alteration', and that whatever 'comes-to-be' in the proper
sense of the term is 'being altered': but those who make the matter of things more than one must distinguish
coming-to-be from 'alteration'. To this latter class belong Empedocles, Anaxagoras, and Leucippus. And yet
Anaxagoras himself failed to understand his own utterance. He says, at all events, that coming-to-be and
passing-away are the same as 'being altered':' yet, in common with other thinkers, he affirms that the
elements are many. Thus Empedocles holds that the corporeal elements are four, while all the
elements-including those which initiate movement-are six in number; whereas Anaxagoras agrees with
Leucippus and Democritus that the elements are infinite.

(Anaxagoras posits as elements the 'homoeomeries', viz. bone, flesh, marrow, and everything else which is
such that part and whole are the same in name and nature; while Democritus and Leucippus say that there are
indivisible bodies, infinite both in number and in the varieties of their shapes, of which everything else is
composed-the compounds differing one from another according to the shapes, 'positions', and 'groupings' of
their constituents.)

For the views of the school of Anaxagoras seem diametrically opposed to those of the followers of
Empedocles. Empedocles says that Fire, Water, Air, and Earth are four elements, and are thus 'simple' rather
than flesh, bone, and bodies which, like these, are 'homoeomeries'. But the followers of Anaxagoras regard
the 'homoeomeries' as 'simple' and elements, whilst they affirm that Earth, Fire, Water, and Air are
composite; for each of these is (according to them) a 'common seminary' of all the 'homoeomeries'.

Those, then, who construct all things out of a single element, must maintain that coming-tobe and
passing-away are 'alteration'. For they must affirm that the underlying something always remains identical
and one; and change of such a substratum is what we call 'altering' Those, on the other hand, who make the
ultimate kinds of things more than one, must maintain that 'alteration' is distinct from coming-to-be: for
coming-to-be and passingaway result from the consilience and the dissolution of the many kinds. That is
why Empedocles too uses language to this effect, when he says There is no coming-to-be of anything, but
only a mingling and a divorce of what has been mingled'. Thus it is clear (i) that to describe coming-to-be
and passing-away in these terms is in accordance with their fundamental assumption, and (ii) that they do in
fact so describe them: nevertheless, they too must recognize 'alteration' as a fact distinct from coming to-be,
though it is impossible for them to do so consistently with what they say.

That we are right in this criticism is easy to perceive. For 'alteration' is a fact of observation. While the
substance of the thing remains unchanged, we see it 'altering' just as we see in it the changes of magnitude
called 'growth' and 'diminution'. Nevertheless, the statements of those who posit more 'original reals' than one
make 'alteration' impossible. For 'alteration, as we assert, takes place in respect to certain qualities: and these
qualities (I mean, e.g. hot-cold, white-black, dry-moist, soft-hard, and so forth) are, all of them, differences
characterizing the 'elements'. The actual words of Empedocles may be quoted in illustration-

The sun everywhere bright to see, and hot,
The rain everywhere dark and cold;

and he distinctively characterizes his remaining elements in a similar manner. Since, therefore, it is not
possible for Fire to become Water, or Water to become Earth, neither will it be possible for anything white to
become black, or anything soft to become hard; and the same argument applies to all the other qualities. Yet
this is what 'alteration' essentially is.

It follows, as an obvious corollary, that a single matter must always be assumed as underlying the contrary
'poles' of any change whether change of place, or growth and diminution, or 'alteration'; further, that the being
of this matter and the being of 'alteration' stand and fall together. For if the change is 'alteration', then the

ON GENERATION AND CORRUPTION 2

ON GENERATION AND CORRUPTION

substratum is a single element; i.e. all things which admit of change into one another have a single matter.
And, conversely, if the substratum of the changing things is one, there is 'alteration'.

Empedocles, indeed, seems to contradict his own statements as well as the observed facts. For he denies that
any one of his elements comes-to-be out of any other, insisting on the contrary that they are the things out of
which everything else comes-to-be; and yet (having brought the entirety of existing things, except Strife,
together into one) he maintains, simultaneously with this denial, that each thing once more comes-to-be out
of the One. Hence it was clearly out of a One that this came-to-be Water, and that Fire, various portions of it
being separated off by certain characteristic differences or qualities-as indeed he calls the sun 'white and hot',
and the earth 'heavy and hard'. If, therefore, these characteristic differences be taken away (for they can be
taken away, since they came-to-be), it will clearly be inevitable for Earth to come to-be out of Water and
Water out of Earth, and for each of the other elements to undergo a similar transformation-not only then, but
also now-if , and because, they change their qualities. And, to judge by what he says, the qualities are such
that they can be 'attached' to things and can again be 'separated' from them, especially since Strife and Love
are still fighting with one another for the mastery. It was owing to this same conflict that the elements were
generated from a One at the former period. I say 'generated', for presumably Fire, Earth, and Water had no
distinctive existence at all while merged in one.

There is another obscurity in the theory Empedocles. Are we to regard the One as his 'original real'? Or is it
the Many-i.e. Fire and Earth, and the bodies co-ordinate with these? For the One is an 'element' in so far as it
underlies the process as matter-as that out of which Earth and Fire come-to-be through a change of qualities
due to 'the motion'. On the other hand, in so far as the One results from composition (by a consilience of the
Many), whereas they result from disintegration the Many are more 'elementary' than the One, and prior to it
in their nature.

We have therefore to discuss the whole subject of 'unqualified' coming-to-be and passingaway; we have to
inquire whether these changes do or do not occur and, if they occur, to explain the precise conditions of their
occurrence. We must also discuss the remaining forms of change, viz. growth and 'alteration'. For though, no
doubt, Plato investigated the conditions under which things come-to-be and pass-away, he confined his
inquiry to these changes; and he discussed not all coming-to-be, but only that of the elements. He asked no
questions as to how flesh or bones, or any of the other similar compound things, come-to-be; nor again did
he examine the conditions under which 'alteration' or growth are attributable to things.

A similar criticism applies to all our predecessors with the single exception of Democritus. Not one of them
penetrated below the surface or made a thorough examination of a single one of the problems. Democritus,
however, does seem not only to have thought carefully about all the problems, but also to be distinguished
from the outset by his method. For, as we are saying, none of the other philosophers made any definite
statement about growth, except such as any amateur might have made. They said that things grow 'by the
accession of like to like', but they did not proceed to explain the manner of this accession. Nor did they give
any account of 'combination': and they neglected almost every single one of the remaining problems, offering
no explanation, e.g. of 'action' or 'passion' how in physical actions one thing acts and the other undergoes
action. Democritus and Leucippus, however, postulate the 'figures', and make 'alteration' and coming-to-be
result from them. They explain coming-to-be and passing-away by their 'dissociation' and 'association', but
'alteration' by their 'grouping' and 'Position'. And since they thought that the 'truth lay in the appearance, and
the appearances are conflicting and infinitely many, they made the 'figures' infinite in number. Hence-owing
to the changes of the compound-the same thing seems different and conflicting to different people: it is
'transposed' by a small additional ingredient, and appears utterly other by the 'transposition' of a single
constituent. For Tragedy and Comedy are both composed of the same letters.

ON GENERATION AND CORRUPTION

Since almost all our predecessors think (i) that coming-to-be is distinct from 'alteration', and (ii) that,
whereas things 'alter' by change of their qualities, it is by 'association' and 'dissociation' that they come-to-be
and pass-away, we must concentrate our attention on these theses. For they lead to many perplexing and
well-grounded dilemmas. If, on the one hand, coming-to-be is 'association', many impossible consequences
result: and yet there are other arguments, not easy to unravel, which force the conclusion upon us that
coming-to-be cannot possibly be anything else. If, on the other hand, coming-to-be is not 'association',
either there is no such thing as coming-to-be at all or it is 'alteration': or else we must endeavour to unravel
this dilemma too-and a stubborn one we shall find it. The fundamental question, in dealing with all these
difficulties, is this: 'Do things come-to-be and "alter" and grow, and undergo the contrary changes, because
the primary "reals" are indivisible magnitudes? Or is no magnitude indivisible?' For the answer we give to
this question makes the greatest difference. And again, if the primary 'reals' are indivisible magnitudes, are
these bodies, as Democritus and Leucippus maintain? Or are they planes, as is asserted in the Timaeus?

To resolve bodies into planes and no further-this, as we have also remarked elsewhere, in itself a paradox.
Hence there is more to be said for the view that there are indivisible bodies. Yet even these involve much of
paradox. Still, as we have said, it is possible to construct 'alteration' and coming-to-be with them, if one
'transposes' the same by 'turning' and 'intercontact', and by 'the varieties of the figures', as Democritus does.
(His denial of the reality of colour is a corollary from this position: for, according to him, things get coloured
by 'turning' of the 'figures'.) But the possibility of such a construction no longer exists for those who divide
bodies into planes. For nothing except solids results from putting planes together: they do not even attempt to
generate any quality from them.

Lack of experience diminishes our power of taking a comprehensive view of the admitted facts. Hence those
who dwell in intimate association with nature and its phenomena grow more and more able to formulate, as
the foundations of their theories, principles such as to admit of a wide and coherent development: while those
whom devotion to abstract discussions has rendered unobservant of the facts are too ready to dogmatize on
the basis of a few observations. The rival treatments of the subject now before us will serve to illustrate how
great is the difference between a 'scientific' and a 'dialectical' method of inquiry. For, whereas the Platonists
argue that there must be atomic magnitudes 'because otherwise "The Triangle" will be more than one',
Democritus would appear to have been convinced by arguments appropriate to the subject, i.e. drawn from
the science of nature. Our meaning will become clear as we proceed. For to suppose that a body (i.e. a
magnitude) is divisible through and through, and that this division is possible, involves a difficulty. What will
there be in the body which escapes the division?

If it is divisible through and through, and if this division is possible, then it might be, at one and the same
moment, divided through and through, even though the dividings had not been effected simultaneously: and
the actual occurrence of this result would involve no impossibility. Hence the same principle will apply
whenever a body is by nature divisible through and through, whether by bisection, or generally by any
method whatever: nothing impossible will have resulted if it has actually been divided-not even if it has been
divided into innumerable parts, themselves divided innumerable times. Nothing impossible will have
resulted, though perhaps nobody in fact could so divide it.

Since, therefore, the be dy is divisible through and through, let it have been divided. What, then, will remain?
A magnitude? No: that is impossible, since then there will be something not divided, whereas ex hypothesis
the body was divisible through and through. But if it be admitted that neither a body nor a magnitude will
remain, and yet division is to take place, the constituents of the body will either be points (i.e. without
magnitude) or absolutely nothing. If its constituents are nothings, then it might both come-to-be out of
nothings and exist as a composite of nothings: and thus presumably the whole body will be nothing but an
appearance. But if it consists of points, a similar absurdity will result: it will not possess any magnitude. For
when the points were in contact and coincided to form a single magnitude, they did not make the whole any
bigger (since, when the body was divided into two or more parts, the whole was not a bit smaller or bigger

ON GENERATION AND CORRUPTION

than it was before the division): hence, even if all the points be put together, they will not make any
magnitude.

But suppose that, as the body is being divided, a minute section-a piece of sawdust, as it were-is extracted,
and that in this sense-a body 'comes away' from the magnitude, evading the division. Even then the same
argument applies. For in what sense is that section divisible? But if what 'came away' was not a body but a
separable form or quality, and if the magnitude is 'points or contacts thus qualified': it is paradoxical that a
magnitude should consist of elements, which are not magnitudes. Moreover, where will the points be? And
are they motionless or moving? And every contact is always a contact of two somethings, i.e. there is always
something besides the contact or the division or the point.

These, then, are the difficulties resulting from the supposition that any and every body, whatever its size, is
divisible through and through. There is, besides, this further consideration. If, having divided a piece of wood
or anything else, I put it together, it is again equal to what it was, and is one. Clearly this is so, whatever the
point at which I cut the wood. The wood, therefore, has been divided potentially through and through. What,
then, is there in the wood besides the division? For even if we suppose there is some quality, yet how is the
wood dissolved into such constituents and how does it come-to-be out of them? Or how are such
constituents separated so as to exist apart from one another? Since, therefore, it is impossible for magnitudes
to consist of contacts or points, there must be indivisible bodies and magnitudes. Yet, if we do postulate the
latter, we are confronted with equally impossible consequences, which we have examined in other works.'
But we must try to disentangle these perplexities, and must therefore formulate the whole problem over
again.

On the one hand, then, it is in no way paradoxical that every perceptible body should be indivisible as well as
divisible at any and every point. For the second predicate will at. tach to it potentially, but the first actually.
On the other hand, it would seem to be impossible for a body to be, even potentially, divisible at all points
simultaneously. For if it were possible, then it might actually occur, with the result, not that the body would
simultaneously be actually both (indivisible and divided), but that it would be simultaneously divided at any
and every point. Consequently, nothing will remain and the body will have passed-away into what is
incorporeal: and so it might come-to-be again either out of points or absolutely out of nothing. And how is
that possible?

But now it is obvious that a body is in fact divided into separable magnitudes which are smaller at each
division-into magnitudes which fall apart from one another and are actually separated. Hence (it is urged) the
process of dividing a body part by part is not a 'breaking up' which could continue ad infinitum; nor can a
body be simultaneously divided at every point, for that is not possible; but there is a limit, beyond which the
'breaking up' cannot proceed. The necessary consequence-especially if coming-to-be and passing-away are
to take place by 'association' and 'dissociation' respectively-is that a body must contain atomic magnitudes
which are invisible. Such is the argument which is believed to establish the necessity of atomic magnitudes:
we must now show that it conceals a faulty inference, and exactly where it conceals it.

For, since point is not 'immediately-next' to point, magnitudes are 'divisible through and through' in one
sense, and yet not in another. When, however, it is admitted that a magnitude is 'divisible through and
through', it is thought there is a point not only anywhere, but also everywhere, in it: hence it is supposed to
follow, from the admission, that the magnitude must be divided away into nothing. For it is supposed-there is
a point everywhere within it, so that it consists either of contacts or of points. But it is only in one sense that
the magnitude is 'divisible through and through', viz. in so far as there is one point anywhere within it and all
its points are everywhere within it if you take them singly one by one. But there are not more points than one
anywhere within it, for the points are not 'consecutive': hence it is not simultaneously 'divisible through and
through'. For if it were, then, if it be divisible at its centre, it will be divisible also at a point
'immediately-next' to its centre. But it is not so divisible: for position is not 'immediately-next' to position,

ON GENERATION AND CORRUPTION

nor point to point-in other words, division is not 'immediately-next' to division, nor composition to
composition.

Hence there are both 'association' and 'dissociation', though neither (a) into, and out of, atomic magnitudes
(for that involves many impossibilities), nor (b) so that division takes place through and through-for this
would have resulted only if point had been 'immediately-next' to point: but 'dissociation' takes place into
small (i.e. relatively small) parts, and 'association' takes place out of relatively small parts.

It is wrong, however, to suppose, as some assert, that coming-to-be and passing-away in the unqualified and
complete sense are distinctively defined by 'association' and 'dissociation', while the change that takes place
in what is continuous is 'alteration'. On the contrary, this is where the whole error lies. For unqualified
coming-to-be and passing-away are not effected by 'association' and 'dissociation'. They take place when a
thing changes, from this to that, as a whole. But the philosophers we are criticizing suppose that all such
change is 'alteration': whereas in fact there is a difference. For in that which underlies the change there is a
factor corresponding to the definition and there is a material factor. When, then, the change is in these
constitutive factors, there will be coming-to-be or passing-away: but when it is in the thing's qualities, i.e. a
change of the thing per accidents, there will be 'alteration'.

'Dissociation' and 'association' affect the thing's susceptibility to passing-away. For if water has first been
'dissociated' into smallish drops, air comes-to-be out of it more quickly: while, if drops of water have first
been 'associated', air comes-to-be more slowly. Our doctrine will become clearer in the sequel.' Meantime,
so much may be taken as established-viz. that coming-to-be cannot be 'association', at least not the kind of
'association' some philosophers assert it to be.

Now that we have established the preceding distinctions, we must first consider whether there is anything
which comes-to-be and passes-away in the unqualified sense: or whether nothing comes-to-be in this strict
sense, but everything always comes-to-be something and out of something-I mean, e.g.
comes-to-be-healthy out of being-ill and ill out of being-healthy, comes-to-be-small out of being big and
big out of being-small, and so on in every other instance. For if there is to be coming-to-be without
qualification, 'something' must-without qualification-'come-to-be out of not-being', so that it would be true
to say that 'not-being is an attribute of some things'. For qualified coming-to-be is a process out of qualified
not-being (e.g. out of not-white or not-beautiful), but unqualified coming-to-be is a process out of
unqualified not-being.

Now 'unqulified' means either (i) the primary predication within each Category, or (ii) the universal, i.e. the
all-comprehensive, predication. Hence, if unqualified not-being 'means the negation of 'being' in the sense of
the primary term of the Category in question, we shall have, in 'unqualified coming-to-be', a coming-to-be
of a substance out of not-substance. But that which is not a substance or a 'this' clearly cannot possess
predicates drawn from any of the other Categories either-e.g. we cannot attribute to it any quality, quantity,
or position. Otherwise, properties would admit of existence in separation from substances. If, on the other
hand, 'unqualified not-being' means 'what is not in any sense at all', it will be a universal negation of all
forms of being, so that what comes-to-be will have to come-to-be out of nothing.

Although we have dealt with these problems at greater length in another work, where we have set forth the
difficulties and established the distinguishing definitions, the following concise restatement of our results
must here be offered: In one sense things come-to-be out of that which has no 'being' without qualification:
yet in another sense they come-to-be always out of what is'. For coming-to-be necessarily implies the
pre-existence of something which potentially 'is', but actually 'is not'; and this something is spoken of both as

ON GENERATION AND CORRUPTION

'being' and as 'not-being'.

These distinctions may be taken as established: but even then it is extraordinarily difficult to see how there
can be 'unqualified coming-to-be' (whether we suppose it to occur out of what potentially 'is', or in some
other way), and we must recall this problem for further examination. For the question might be raised
whether substance (i.e. the 'this') comes-to-be at all. Is it not rather the 'such', the 'so great', or the
'somewhere', which comes-to-be? And the same question might be raised about 'passing-away' also. For if a
substantial thing comes-to-be, it is clear that there will 'be' (not actually, but potentially) a substance, out of
which its coming-to-be will proceed and into which the thing that is passing-away will necessarily change.
Then will any predicate belonging to the remaining Categories attach actually to this presupposed substance?
In other words, will that which is only potentially a 'this' (which only potentially is), while without the
qualification 'potentially' it is not a 'this' (i.e. is not), possess, e.g. any determinate size or quality or position?
For (i) if it possesses none of these determinations actually, but all of them only potentially, the result is first
that a being, which is not a determinate being, is capable of separate existence; and in addition that
coming-to-be proceeds out of nothing pre-existing-a thesis which, more than any other, preoccupied and
alarmed the earliest philosophers. On the other hand (ii) if, although it is not a 'this somewhat' or a substance,
it is to possess some of the remaining determinations quoted above, then (as we said)' properties will be
separable from substances.

We must therefore concentrate all our powers on the discussion of these difficulties and on the solution of a
further question-viz. What is the cause of the perpetuity of coming-to-be? Why is there always unqualified,
as well as partial, coming-to-be? Cause' in this connexion has two senses. It means (i) the source from
which, as we say, the process 'originates', and (ii) the matter. It is the material cause that we have here to
state. For, as to the other cause, we have already explained (in our treatise on Motion that it involves (a)
something immovable through all time and (b) something always being moved. And the accurate treatment of
the first of these-of the immovable 'originative source-belongs to the province of the other, or 'prior',
philosophy: while as regards 'that which sets everything else in motion by being itself continuously moved',
we shall have to explain later' which amongst the so-called 'specific' causes exhibits this character. But at
present we are to state the material cause-the cause classed under the head of matter-to which it is due that
passing-away and coming-to-be never fail to occur in Nature. For perhaps, if we succeed in clearing up this
question, it will simultaneously become clear what account we ought to give of that which perplexed us just
now, i.e. of unqualified passingaway and coming-to-be.

Our new question too-viz. 'what is the cause of the unbroken continuity of coming-to-be?'-is sufficiently
perplexing, if in fact what passes-away vanishes into 'what is not' and 'what is not' is nothing (since 'what is
not' is neither a thing, nor possessed of a quality or quantity, nor in any place). If, then, some one of the
things 'which are' constantly disappearing, why has not the whole of 'what is' been used up long ago and
vanished away assuming of course that the material of all the several comings-to-be was finite? For,
presumably, the unfailing continuity of coming-to-be cannot be attributed to the infinity of the material.
That is impossible, for nothing is actually infinite. A thing is infinite only potentially, i.e. the dividing of it
can continue indefinitely: so that we should have to suppose there is only one kind of coming-to-be in the
world-viz. one which never fails, because it is such that what comes-to-be is on each successive occasion
smaller than before. But in fact this is not what we see occurring.

Why, then, is this form of change necessarily ceaseless? Is it because the passing-away of this is a
coming-to-be of something else, and the coming-to-be of this a passing-away of something else?

The cause implied in this solution must no doubt be considered adequate to account for coming-to-be and
passing-away in their general character as they occur in all existing things alike. Yet, if the same process is a
coming to-be of this but a passing-away of that, and a passing-away of this but a coming-to-be of that, why
are some things said to come-to-be and pass-away without qualification, but others only with a

ON GENERATION AND CORRUPTION

qualification?

The distinction must be investigated once more, for it demands some explanation. (It is applied in a twofold
manner.) For (i) we say 'it is now passing-away' without qualification, and not merely 'this is passing-away':
and we call this change 'coming-to-be', and that 'passing-away', without qualification. And (ii) so-and-so
'comes-to-be-something', but does not 'come-to-be' without qualification; for we say that the student
'comes-to-be-learned', not 'comes-to-be' without qualification.

(i) Now we often divide terms into those which signify a 'this somewhat' and those which do not. And (the
first form of) the distinction, which we are investigating, results from a similar division of terms: for it makes
a difference into what the changing thing changes. Perhaps, e.g. the passage into Fire is 'coming-to-be'
unqualified, but 'passingaway-of-something' (e.g. Earth): whilst the coming-to-be of Earth is qualified (not
unqualified) 'coming-to-be', though unqualified 'passing-away' (e.g. of Fire). This would be the case on the
theory set forth in Parmenides: for he says that the things into which change takes place are two, and he
asserts that these two, viz. what is and what is not, are Fire and Earth. Whether we postulate these, or other
things of a similar kind, makes no difference. For we are trying to discover not what undergoes these
changes, but what is their characteristic manner. The passage, then, into what 'is' not except with a
qualification is unqualified passing-away, while the passage into what 'is' without qualification is unqualified
coming-to-be. Hence whatever the contrasted 'poles' of the changes may be whether Fire and Earth, or some
other couple-the one of them will be 'a being' and the other 'a not-being'.

We have thus stated one characteristic manner in which unqualified will be distinguished from qualified
coming-to-be and passing-away: but they are also distinguished according to the special nature of the
material of the changing thing. For a material, whose constitutive differences signify more a 'this somewhat',
is itself more 'substantial' or 'real': while a material, whose constitutive differences signify privation, is 'not
real'. (Suppose, e.g. that 'the hot' is a positive predication, i.e. a 'form', whereas 'cold' is a privation, and that
Earth and Fire differ from one another by these constitutive differences.)

The opinion, however, which most people are inclined to prefer, is that the distinction depends upon the
difference between 'the perceptible' and 'the imperceptible'. Thus, when there is a change into perceptible
material, people say there is 'coming-to-be'; but when there is a change into invisible material, they call it
'passing-away'. For they distinguish 'what is' and 'what is not' by their perceiving and not-perceiving, just as
what is knowable 'is' and what is unknowable 'is not' -perception on their view having the force of
knowledge. Hence, just as they deem themselves to live and to 'be' in virtue of their perceiving or their
capacity to perceive, so too they deem the things to 'be' qua perceived or perceptible-and in this they are in a
sense on the track of the truth, though what they actually say is not true.

Thus unqualified coming-to-be and passingaway turn out to be different according to common opinion from
what they are in truth. For Wind and Air are in truth more real more a 'this somewhat' or a 'form'-than Earth.
But they are less real to perception which explains why things are commonly said to 'pass-away' without
qualification when they change into Wind and Air, and to 'come-to-be' when they change into what is
tangible, i.e. into Earth.

We have now explained why there is 'unqualified coming-to-be' (though it is a passingaway-of-something)
and 'unqualified passingaway (though it is a coming-to-be-of-something). For this distinction of appellation
depends upon a difference in the material out of which, and into which, the changes are effected. It depends
either upon whether the material is or is not 'substantial', or upon whether it is more or less 'substantial', or
upon whether it is more or less perceptible.

(ii) But why are some things said to 'come to-be' without qualification, and others only to
'come-to-be-so-and-so', in cases different from the one we have been considering where two things

ON GENERATION AND CORRUPTION

come-to-be reciprocally out of one another? For at present we have explained no more than this:-why, when
two things change reciprocally into one another, we do not attribute coming-to-be and passing-away
uniformly to them both, although every coming-to-be is a passing-away of something else and every
passing-away some other thing's coming-to-be. But the question subsequently formulated involves a
different problem-viz. why, although the learning thing is said to 'come-to-be-learned' but not to
'come-tobe' without qualification, yet the growing thing is said to 'come-to-be'.

The distinction here turns upon the difference of the Categories. For some things signify a this somewhat,
others a such, and others a so-much. Those things, then, which do not signify substance, are not said to
'come-to-be' without qualification, but only to 'come-to-be-so-and-so'. Nevertheless, in all changing
things alike, we speak of 'coming-to-be' when the thing comes-to-be something in one of the two
Columns-e.g. in Substance, if it comes-to-be Fire but not if it comes-to-be Earth; and in Quality, if it
comes-to-be learned but not when it comes-to-be ignorant.

We have explained why some things come to-be without qualification, but not others both in general, and
also when the changing things are substances and nothing else; and we have stated that the substratum is the
material cause of the continuous occurrence of coming to-be, because it is such as to change from contrary to
contrary and because, in substances, the coming-to-be of one thing is always a passing-away of another, and
the passing-away of one thing is always another's coming-to-be. But there is no need even to discuss the
other question we raised-viz. why coming-to-be continues though things are constantly being destroyed. For
just as people speak of 'a passing-away' without qualification when a thing has passed into what is
imperceptible and what in that sense 'is not', so also they speak of 'a coming-to-be out of a not-being' when
a thing emerges from an imperceptible. Whether, therefore, the substratum is or is not something, what
comes-tobe emerges out of a 'not-being': so that a thing comes-to-be out of a not-being' just as much as it
'passes-away into what is not'. Hence it is reasonable enough that coming-to-be should never fail. For
coming-to-be is a passing-away of 'what is not' and passing-away is a coming to-be of 'what is not'.

But what about that which 'is' not except with a qualification? Is it one of the two contrary poles of the
chang-e.g. Earth (i.e. the heavy) a 'not-being', but Fire (i.e. the light) a 'being'? Or, on the contrary, does
what is 'include Earth as well as Fire, whereas what is not' is matter-the matter of Earth and Fire alike? And
again, is the matter of each different? Or is it the same, since otherwise they would not come-to-be
reciprocally out of one another, i.e. contraries out of contraries? For these things-Fire, Earth, Water, Air-are
characterized by 'the contraries'.

Perhaps the solution is that their matter is in one sense the same, but in another sense different. For that which
underlies them, whatever its nature may be qua underlying them, is the same: but its actual being is not the
same. So much, then, on these topics.

Next we must state what the difference is between coming-to-be and 'alteration'-for we maintain that these
changes are distinct from one another.

Since, then, we must distinguish (a) the substratum, and (b) the property whose nature it is to be predicated of
the substratum; and since change of each of these occurs; there is 'alteration' when the substratum is
perceptible and persists, but changes in its own properties, the properties in question being opposed to one
another either as contraries or as intermediates. The body, e.g. although persisting as the same body, is now
healthy and now ill; and the bronze is now spherical and at another time angular, and yet remains the same
bronze. But when nothing perceptible persists in its identity as a substratum, and the thing changes as a whole
(when e.g. the seed as a whole is converted into blood, or water into air, or air as a whole into water), such an

ON GENERATION AND CORRUPTION

occurrence is no longer 'alteration'. It is a coming-to-be of one substance and a passing-away of the
other-especially if the change proceeds from an imperceptible something to something perceptible (either to
touch or to all the senses), as when water comes-to-be out of, or passes-away into, air: for air is pretty well
imperceptible. If, however, in such cases, any property (being one of a pair of contraries) persists, in the thing
that has come-to-be, the same as it was in the thing which has passedaway-if, e.g. when water comes-to-be
out of air, both are transparent or cold-the second thing, into which the first changes, must not be a property
of this persistent identical something. Otherwise the change will be 'alteration.' Suppose, e.g. that the musical
man passed-away and an unmusical man came-tobe, and that the man persists as something identical. Now,
if 'musicalness and unmusicalness' had not been a property essentially inhering in man, these changes would
have been a coming-to-be of unmusicalness and a passing-away of musicalness: but in fact 'musicalness and
unmusicalness' are a property of the persistent identity, viz. man. (Hence, as regards man, these changes are
'modifications'; though, as regards musical man and unmusical man, they are a passing-away and a
coming-to-be.) Consequently such changes are 'alteration.' When the change from contrary to contrary is in
quantity, it is 'growth and diminution'; when it is in place, it is 'motion'; when it is in property, i.e. in quality,
it is 'alteration': but, when nothing persists, of which the resultant is a property (or an 'accident' in any sense
of the term), it is 'coming-to-be', and the converse change is 'passing-away'.

'Matter', in the most proper sense of the term, is to be identified with the substratum which is receptive of
coming-to-be and passingaway: but the substratum of the remaining kinds of change is also, in a certain
sense, 'matter', because all these substrata are receptive of 'contrarieties' of some kind. So much, then, as an
answer to the questions (i) whether coming-to-be 'is' or 'is not'-i.e. what are the precise conditions of its
occurrence and (ii) what 'alteration' is: but we have still to treat of growth.

We must explain (i) wherein growth differs from coming-to-be and from 'alteration', and ii) what is the
process of growing and the sprocess of diminishing in each and all of the things that grow and diminish.

Hence our first question is this: Do these changes differ from one another solely because of a difference in
their respective 'spheres'? In other words, do they differ because, while a change from this to that (viz. from
potential to actual substance) is coming-to-be, a change in the sphere of magnitude is growth and one in the
sphere of quality is 'alteration'-both growth and 'alteration' being changes from what is-potentially to what
is-actually magnitude and quality respectively? Or is there also a difference in the manner of the change,
since it is evident that, whereas neither what is 'altering' nor what is coming-to-be necessarily changes its
place, what is growing or diminishing changes its spatial position of necessity, though in a different manner
from that in which the moving thing does so? For that which is being moved changes its place as a whole: but
the growing thing changes its place like a metal that is being beaten, retaining its position as a whole while its
parts change their places. They change their places, but not in the same way as the parts of a revolving globe.
For the parts of the globe change their places while the whole continues to occupy an equal place: but the
parts of the rowing thing expand over an ever-increasing place and the parts of the diminishing thing contract
within an ever-diminishing area.

It is clear, then, that these changes-the changes of that which is coming-to-be, of that which is 'altering', and
of that which is growing-differ in manner as well as in sphere. But how are we to conceive the 'sphere' of the
change which is growth and diminution? The sphere' of growing and diminishing is believed to be
magnitude. Are we to suppose that body and magnitude come-to-be out of something which, though
potentially magnitude and body, is actually incorporeal and devoid of magnitude? And since this description
may be understood in two different ways, in which of these two ways are we to apply it to the process of
growth? Is the matter, out of which growth takes place, (i) 'separate' and existing alone by itself, or (ii)
'separate' but contained in another body?

5 10

ON GENERATION AND CORRUPTION

Perhaps it is impossible for growth to take place in either of these ways. For since the matter is 'separate',
either (a) it will occupy no place (as if it were a point), or (b) it will be a 'void', i.e. a non-perceptible body.
But the first of these alternatives is impossible. For since what comes-to-be out of this incorporeal and
sizeless something will always be 'somewhere', it too must be 'somewhere'-either intrinsically or indirectly.
And the second alternative necessarily implies that the matter is contained in some other body. But if it is to
be 'in' another body and yet remains 'separate' in such a way that it is in no sense a part of that body (neither a
part of its substantial being nor an 'accident' of it), many impossibilities will result. It is as if we were to
suppose that when, e.g. air comes-to-be out of water the process were due not to a change of the but to the
matter of the air being 'contained in' the water as in a vessel. This is impossible. For (i) there is nothing to
prevent an indeterminate number of matters being thus 'contained in' the water, so that they might
come-to-be actually an indeterminate quantity of air; and (ii) we do not in fact see air coming-to-be out of
water in this fashion, viz. withdrawing out of it and leaving it unchanged.

It is therefore better to suppose that in all instances of coming-to-be the matter is inseparable, being
numerically identical and one with the 'containing' body, though isolable from it by definition. But the same
reasons also forbid us to regard the matter, out of which the body comes-to-be, as points or lines. The matter
is that of which points and lines are limits, and it is something that can never exist without quality and
without form.

Now it is no doubt true, as we have also established elsewhere,' that one thing 'comes-tobe' (in the
unqualified sense) out of another thing: and further it is true that the efficient cause of its coming-to-be is
either (i) an actual thing (which is the same as the effect either generic ally-or the efficient cause of the
coming-to-be of a hard thing is not a hard thing or specifically, as e.g. fire is the efficient cause of the
coming-to-be of fire or one man of the birth of another), or (ii) an actuality. Nevertheless, since there is also
a matter out of which corporeal substance itself comes-to-be (corporeal substance, however, already
characterized as such-and-such a determinate body, for there is no such thing as body in general), this same
matter is also the matter of magnitude and quality-being separable from these matters by definition, but not
separable in place unless Qualities are, in their turn, separable.

It is evident, from the preceding development and discussion of difficulties, that growth is not a change out of
something which, though potentially a magnitude, actually possesses no magnitude. For, if it were, the 'void'
would exist in separation; but we have explained in a former work' that this is impossible. Moreover, a
change of that kind is not peculiarly distinctive of growth, but characterizes coming-to-be as such or in
general. For growth is an increase, and diminution is a lessening, of the magnitude which is there
already-that, indeed, is why the growing thing must possess some magnitude. Hence growth must not be
regarded as a process from a matter without magnitude to an actuality of magnitude: for this would be a
body's coming-to-be rather than its growth.

We must therefore come to closer quarters with the subject of our inquiry. We must grapple' with it (as it
were) from its beginning, and determine the precise character of the growing and diminishing whose causes
we are investigating.

It is evident (i) that any and every part of the growing thing has increased, and that similarly in diminution
every part has become smaller: also (ii) that a thing grows by the accession, and diminishes by the departure,
of something. Hence it must grow by the accession either (a) of something incorporeal or (b) of a body. Now,
if (a) it grows by the accession of something incorporeal, there will exist separate a void: but (as we have
stated before)' is impossible for a matter of magnitude to exist 'separate'. If, on the other hand (b) it grows by
the accession of a body, there will be two bodies-that which grows and that which increases it-in the same
place: and this too is impossible.

ON GENERATION AND CORRUPTION

But neither is it open to us to say that growth or diminution occurs in the way in which e.g. air is generated
from water. For, although the volume has then become greater, the change will not be growth, but a coming
to-be of the one-viz. of that into which the change is taking place-and a passing-away of the contrasted
body. It is not a growth of either. Nothing grows in the process; unless indeed there be something common to
both things (to that which is coming-to-be and to that which passed-away), e.g. 'body', and this grows. The
water has not grown, nor has the air: but the former has passed-away and the latter has come-to-be, and-if
anything has grown-there has been a growth of 'body.' Yet this too is impossible. For our account of growth
must preserve the characteristics of that which is growing and diminishing. And these characteristics are
three: (i) any and every part of the growing magnitude is made bigger (e.g. if flesh grows, every particle of
the flesh gets bigger), (ii) by the accession of something, and (iii) in such a way that the growing thing is
preserved and persists. For whereas a thing does not persist in the processes of unqualified coming-to-be or
passing-away, that which grows or 'alters' persists in its identity through the 'altering' and through the
growing or diminishing, though the quality (in 'alteration') and the size (in growth) do not remain the same.
Now if the generation of air from water is to be regarded as growth, a thing might grow without the accession
(and without the persistence) of anything, and diminish without the departure of anything-and that which
grows need not persist. But this characteristic must be preserved: for the growth we are discussing has been
assumed to be thus characterized.

One might raise a further difficulty. What is 'that which grows'? Is it that to which something is added? If,
e.g. a man grows in his shin, is it the shin which is greater-but not that 'whereby' he grows, viz. not the food?
Then why have not both 'grown'? For when A is added to B, both A and B are greater, as when you mix wine
with water; for each ingredient is alike increased in volume. Perhaps the explanation is that the substance of
the one remains unchanged, but the substance of the other (viz. of the food) does not. For indeed, even in the
mixture of wine and water, it is the prevailing ingredient which is said to have increased in volume. We say,
e.g. that the wine has increased, because the whole mixture acts as wine but not as water. A similar principle
applies also to 'alteration'. Flesh is said to have been 'altered' if, while its character and substance remain,
some one of its essential properties, which was not there before, now qualifies it: on the other hand, that
'whereby' it has been 'altered' may have undergone no change, though sometimes it too has been affected. The
altering agent, however, and the originative source of the process are in the growing thing and in that which is
being 'altered': for the efficient cause is in these. No doubt the food, which has come in, may sometimes
expand as well as the body that has consumed it (that is so, e.g. if, after having come in, a food is converted
into wind), but when it has undergone this change it has passedaway: and the efficient cause is not in the
food.

We have now developed the difficulties sufficiently and must therefore try to find a solution of the problem.
Our solution must preserve intact the three characteristics of growth-that the growing thing persists, that it
grows by the accession (and diminishes by the departure) of something, and further that every perceptible
particle of it has become either larger or smaller. We must recognize also (a) that the growing body is not
'void' and that yet there are not two magnitudes in the same place, and (b) that it does not grow by the
accession of something incorporeal.

Two preliminary distinctions will prepare us to grasp the cause of growth. We must note (i) that the organic
parts grow by the growth of the tissues (for every organ is composed of these as its constituents); and (ii) that
flesh, bone, and every such part-like every other thing which has its form immersed in matter-has a twofold
nature: for the form as well as the matter is called 'flesh' or 'bone'.

Now, that any and every part of the tissue qua form should grow-and grow by the accession of something-is
possible, but not that any and every part of the tissue qua matter should do so. For we must think of the tissue
after the image of flowing water that is measured by one and the same measure: particle after particle
comes-to-be, and each successive particle is different. And it is in this sense that the matter of the flesh
grows, some flowing out and some flowing in fresh; not in the sense that fresh matter accedes to every

5 12

ON GENERATION AND CORRUPTION

particle of it. There is, however, an accession to every part of its figure or 'form'.

That growth has taken place proportionally, is more manifest in the organic parts-e.g. in the hand. For there
the fact that the matter is distinct from the form is more manifest than in flesh, i.e. than in the tissues. That is
why there is a greater tendency to suppose that a corpse still possesses flesh and bone than that it still has a
hand or an arm.

Hence in one sense it is true that any and every part of the flesh has grown; but in another sense it is false. For
there has been an accession to every part of the flesh in respect to its form, but not in respect to its matter.
The whole, however, has become larger. And this increase is due (a) on the one hand to the accession of
something, which is called 'food' and is said to be 'contrary' to flesh, but (b) on the other hand to the
transformation of this food into the same form as that of flesh as if, e.g. 'moist' were to accede to 'dry' and,
having acceded, were to be transformed and to become 'dry'. For in one sense 'Like grows by Like', but in
another sense 'Unlike grows by Unlike'.

One might discuss what must be the character of that 'whereby' a thing grows. Clearly it must be potentially
that which is growing-potentially flesh, e.g. if it is flesh that is growing. Actually, therefore, it must be 'other'
than the growing thing. This 'actual other', then, has passed-away and come-to-be flesh. But it has not been
transformed into flesh alone by itself (for that would have been a coming-to-be, not a growth): on the
contrary, it is the growing thing which has come-to-be flesh (and grown) by the food. In what way, then, has
the food been modified by the growing thing? Perhaps we should say that it has been 'mixed' with it, as if one
were to pour water into wine and the wine were able to convert the new ingredient into wine. And as fire lays
hold of the inflammable, so the active principle of growth, dwelling in the growing thing that which is
actually flesh), lays hold of an acceding food which is potentially flesh and converts it into actual flesh. The
acceding food, therefore, must be together with the growing thing: for if it were apart from it, the change
would be a coming-to-be. For it is possible to produce fire by piling logs on to the already burning fire. That
is 'growth'. But when the logs themselves are set on fire, that is 'coming-to-be'.

'Quantum-in-general' does not come-to-be any more than 'animal' which is neither man nor any other of the
specific forms of animal: what 'animal-in-general' is in coming-to-be, that 'quantum-in-general' is in
growth. But what does come-to-be in growth is flesh or bone-or a hand or arm (i.e. the tissues of these
organic parts). Such things come-to-be, then, by the accession not of quantified-flesh but of a
quantified-something. In so far as this acceding food is potentially the double result e.g. is potentially
so-much-flesh-it produces growth: for it is bound to become actually both so-much and flesh. But in so far
as it is potentially flesh only, it nourishes: for it is thus that 'nutrition' and 'growth' differ by their definition.
That is why a body's' nutrition' continues so long as it is kept alive (even when it is diminishing), though not
its 'growth'; and why nutrition, though 'the same' as growth, is yet different from it in its actual being. For in
so far as that which accedes is potentially 'so much-flesh' it tends to increase flesh: whereas, in so far as it is
potentially 'flesh' only, it is nourishment.

The form of which we have spoken is a kind of power immersed in matter-a duct, as it were. If, then, a
matter accedes-a matter, which is potentially a duct and also potentially possesses determinate quantity the
ducts to which it accedes will become bigger. But if it is no longer able to act-if it has been weakened by the
continued influx of matter, just as water, continually mixed in greater and greater quantity with wine, in the
end makes the wine watery and converts it into water-then it will cause a diminution of the quantum; though
still the form persists.

(In discussing the causes of coming-tobe) we must first investigate the matter, i.e. the so-called 'elements'.
6 13

ON GENERATION AND CORRUPTION

We must ask whether they really are elements or not, i.e. whether each of them is eternal or whether there is a
sense in which they come-to-be: and, if they do come-to-be, whether all of them come-to-be in the same
manner reciprocally out of one another, or whether one amongst them is something primary. Hence we must
begin by explaining certain preliminary matters, about which the statements now current are vague.

For all (the pluralist philosophers)- those who generate the 'elements' as well as those who generate the
bodies that are compounded of the elements- make use of 'dissociation' and 'association', and of 'action' and
'passion'. Now 'association' is 'combination'; but the precise meaning of the process we call 'combining' has
not been explained. Again, (all the monists make use of 'alteration': but) without an agent and a patient there
cannot be 'altering' any more than there can be 'dissociating' and 'associating'. For not only those who
postulate a plurality of elements employ their reciprocal action and passion to generate the compounds: those
who derive things from a single element are equally compelled to introduce 'acting'. And in this respect
Diogenes is right when he argues that 'unless all things were derived from one, reciprocal action and passion
could not have occurred'. The hot thing, e.g. would not be cooled and the cold thing in turn be warmed: for
heat and cold do not change reciprocally into one another, but what changes (it is clear) is the substratum.
Hence, whenever there is action and passion between two things, that which underlies them must be a single
something. No doubt, it is not true to say that all things are of this character: but it is true of all things
between which there is reciprocal action and passion.

But if we must investigate 'action-passion' and 'combination', we must also investigate 'contact'. For action
and passion (in the proper sense of the terms) can only occur between things which are such as to touch one
another; nor can things enter into combination at all unless they have come into a certain kind of contact.
Hence we must give a definite account of these three things- of 'contact', 'combination', and 'acting'.

Let us start as follows. All things which admit of 'combination' must be capable of reciprocal contact: and the
same is true of any two things, of which one 'acts' and the other 'suffers action' in the proper sense of the
terms. For this reason we must treat of 'contact' first, every term which possesses a variety of meaning
includes those various meanings either owing to a mere coincidence of language, or owing to a real order of
derivation in the different things to which it is applied: but, though this may be taken to hold of 'contact' as of
all such terms, it is nevertheless true that contact' in the proper sense applies only to things which have
'position'. And 'position' belongs only to those things which also have a Place': for in so far as we attribute
'contact' to the mathematical things, we must also attribute 'place' to them, whether they exist in separation or
in some other fashion. Assuming, therefore, that 'to touch' is-as we have defined it in a previous work'-'to
have the extremes together', only those things will touch one another which, being separate magnitudes and
possessing position, have their extremes 'together'. And since position belongs only to those things which also
have a 'place', while the primary differentiation of 'place' is the above' and 'the below' (and the similar pairs of
opposites), all things which touch one another will have 'weight' or 'lightness' either both these qualities or
one or the other of them. But bodies which are heavy or light are such as to 'act' and 'suffer action'. Hence it is
clear that those things are by nature such as to touch one another, which (being separate magnitudes) have
their extremes 'together' and are able to move, and be moved by, one another.

The manner in which the 'mover' moves the moved' not always the same: on the contrary, whereas one kind
of 'mover' can only impart motion by being itself moved, another kind can do so though remaining itself
unmoved. Clearly therefore we must recognize a corresponding variety in speaking of the 'acting' thing too:
for the 'mover' is said to 'act' (in a sense) and the 'acting' thing to 'impart motion'. Nevertheless there is a
difference and we must draw a distinction. For not every 'mover' can 'act', if (a) the term 'agent' is to be used
in contrast to 'patient' and (b) 'patient' is to be applied only to those things whose motion is a 'qualitative
affection'-i.e. a quality, like white' or 'hot', in respect to which they are moved' only in the sense that they are
'altered': on the contrary, to 'impart motion' is a wider term than to 'act'. Still, so much, at any rate, is clear:
the things which are 'such as to impart motion', if that description be interpreted in one sense, will touch the
things which are 'such as to be moved by them'-while they will not touch them, if the description be

6 14

ON GENERATION AND CORRUPTION

interpreted in a different sense. But the disjunctive definition of 'touching' must include and distinguish (a)
'contact in general' as the relation between two things which, having position, are such that one is able to
impart motion and the other to be moved, and (b) 'reciprocal contact' as the relation between two things, one
able to impart motion and the other able to be moved in such a way that 'action and passion' are predicable of
them.

As a rule, no doubt, if A touches B, B touches A. For indeed practically all the 'movers' within our ordinary
experience impart motion by being moved: in their case, what touches inevitably must, and also evidently
does, touch something which reciprocally touches it. Yet, if A moves B, it is possible-as we sometimes
express it-for A 'merely to touch' B, and that which touches need not touch a something which touches it.
Nevertheless it is commonly supposed that 'touching' must be reciprocal. The reason of this belief is that
'movers' which belong to the same kind as the 'moved' impart motion by being moved. Hence if anything
imparts motion without itself being moved, it may touch the 'moved' and yet itself be touched by nothing-for
we say sometimes that the man who grieves us 'touches' us, but not that we 'touch' him.

The account just given may serve to distinguish and define the 'contact' which occurs in the things of Nature.

Next in order we must discuss 'action' and 'passion'. The traditional theories on the subject are conflicting. For
(i) most thinkers are unanimous in maintaining (a) that 'like' is always unaffected by 'like', because (as they
argue) neither of two 'likes' is more apt than the other either to act or to suffer action, since all the properties
which belong to the one belong identically and in the same degree to the other; and (b) that 'unlikes', i.e.
'differents', are by nature such as to act and suffer action reciprocally. For even when the smaller fire is
destroyed by the greater, it suffers this effect (they say) owing to its 'contrariety' since the great is contrary to
the small. But (ii) Democritus dissented from all the other thinkers and maintained a theory peculiar to
himself. He asserts that agent and patient are identical, i.e. 'like'. It is not possible (he says) that 'others', i.e.
'differents', should suffer action from one another: on the contrary, even if two things, being 'others', do act in
some way on one another, this happens to them not qua 'others' but qua possessing an identical property.

Such, then, are the traditional theories, and it looks as if the statements of their advocates were in manifest
conflict. But the reason of this conflict is that each group is in fact stating a part, whereas they ought to have
taken a comprehensive view of the subject as a whole. For (i) if A and B are 'like'-absolutely and in all
respects without difference from one another -it is reasonable to infer that neither is in any way affected by
the other. Why, indeed, should either of them tend to act any more than the other? Moreover, if 'like' can be
affected by 'like', a thing can also be affected by itself: and yet if that were so-if 'like' tended in fact to act qua
'like'-there would be nothing indestructible or immovable, for everything would move itself. And (ii) the
same consequence follows if A and B are absolutely 'other', i.e. in no respect identical. Whiteness could not
be affected in any way by line nor line by whiseness-except perhaps 'coincidentally', viz. if the line happened
to be white or black: for unless two things either are, or are composed of, 'contraries', neither drives the other
out of its natural condition. But (iii) since only those things which either involve a 'contrariety' or are
'contraries'-and not any things selected at random-are such as to suffer action and to act, agent and patient
must be 'like' (i.e. identical) in kind and yet 'unlike' (i.e. contrary) in species. (For it is a law of nature that
body is affected by body, flavour by flavour, colour by colour, and so in general what belongs to any kind by
a member of the same kind-the reason being that 'contraries' are in every case within a single identical kind,
and it is 'contraries' which reciprocally act and suffer action.) Hence agent and patient must be in one sense
identical, but in another sense other than (i.e. 'unlike') one another. And since (a) patient and agent are
generically identical (i.e. 'like') but specifically 'unlike', while (b) it is 'contraries' that exhibit this character: it
is clear that 'contraries' and their 'intermediates' are such as to suffer action and to act reciprocally-for indeed
it is these that constitute the entire sphere of passing-away and coming-to-be.

7 15

ON GENERATION AND CORRUPTION

We can now understand why fire heats and the cold thing cools, and in general why the active thing
assimilates to itself the patient. For agent and patient are contrary to one another, and coming-to-be is a
process into the contrary: hence the patient must change into the agent, since it is only thus that coming-to be
will be a process into the contrary. And, again, it is intelligible that the advocates of both views, although
their theories are not the same, are yet in contact with the nature of the facts. For sometimes we speak of the
substratum as suffering action (e.g. of 'the man' as being healed, being warmed and chilled, and similarly in
all the other cases), but at other times we say 'what is cold is 'being warmed', 'what is sick is being healed':
and in both these ways of speaking we express the truth, since in one sense it is the 'matter', while in another
sense it is the 'contrary', which suffers action. (We make the same distinction in speaking of the agent: for
sometimes we say that 'the man', but at other times that 'what is hot', produces heat.) Now the one group of
thinkers supposed that agent and patient must possess something identical, because they fastened their
attention on the substratum: while the other group maintained the opposite because their attention was
concentrated on the 'contraries'. We must conceive the same account to hold of action and passion as that
which is true of 'being moved' and 'imparting motion'. For the 'mover', like the 'agent', has two meanings.
Both (a) that which contains the originative source of the motion is thought to 'impart motion' (for the
originative source is first amongst the causes), and also (b) that which is last, i.e. immediately next to the
moved thing and to the coming-to-be. A similar distinction holds also of the agent: for we speak not only (a)
of the doctor, but also (b) of the wine, as healing. Now, in motion, there is nothing to prevent the firs; mover
being unmoved (indeed, as regards some 'first' movers' this is actually necessary) although the last mover
always imparts motion by being itself moved: and, in action, there is nothing to prevent the first agent being
unaffected, while the last agent only acts by suffering action itself. For agent and patient have not the same
matter, agent acts without being affected: thus the art of healing produces health without itself being acted
upon in any way by that which is being healed. But (b) the food, in acting, is itself in some way acted upon:
for, in acting, it is simultaneously heated or cooled or otherwise affected. Now the art of healing corresponds
to an 'originative source', while the food corresponds to 'the last' (i.e. 'continuous') mover.

Those active powers, then, whose forms are not embodied in matter, are unaffected: but those whose forms
are in matter are such as to be affected in acting. For we maintain that one and the same 'matter' is equally, so
to say, the basis of either of the two opposed things-being as it were a 'kind'; and that that which can he hot
must be made hot, provided the heating agent is there, i.e. comes near. Hence (as we have said) some of the
active powers are unaffected while others are such as to be affected; and what holds of motion is true also of
the active powers. For as in motion 'the first mover' is unmoved, so among the active powers 'the first agent'
is unaffected.

The active power is a 'cause' in the sense of that from which the process originates: but the end, for the sake
of which it takes place, is not 'active'. (That is why health is not 'active', except metaphorically.) For when the
agent is there, the patient he-comes something: but when 'states' are there, the patient no longer becomes but
already is-and 'forms' (i.e. lends') are a kind of 'state'. As to the 'matter', it (qua matter) is passive. Now fire
contains 'the hot' embodied in matter: but a 'hot' separate from matter (if such a thing existed) could not suffer
any action. Perhaps, indeed, it is impossible that 'the hot' should exist in separation from matter: but if there
are any entities thus separable, what we are saying would be true of them.

We have thus explained what action and passion are, what things exhibit them, why they do so, and in what
manner. We must go on to discuss how it is possible for action and passion to take place.

Some philosophers think that the 'last' agent-the 'agent' in the strictest sense-enters in through certain pores,
and so the patient suffers action. It is in this way, they assert, that we see and hear and exercise all our other
senses. Moreover, according to them, things are seen through air and water and other transparent bodies,

8 16

ON GENERATION AND CORRUPTION

because such bodies possess pores, invisible indeed owing to their minuteness, but close-set and arranged in
rows: and the more transparent the body, the more frequent and serial they suppose its pores to be. Such was
the theory which some philosophers (induding Empedocles) advanced in regard to the structure of certain
bodies. They do not restrict it to the bodies which act and suffer action: but 'combination' too, they say, takes
place 'only between bodies whose pores are in reciprocal symmetry'. The most systematic and consistent
theory, however, and one that applied to all bodies, was advanced by Leucippus and Democritus: and, in
maintaining it, they took as their starting-point what naturally comes first.

For some of the older philosophers thought that 'what is' must of necessity be 'one' and immovable. The void,
they argue, 'is not': but unless there is a void with a separate being of its own, 'what is' cannot be moved-nor
again can it be 'many', since there is nothing to keep things apart. And in this respect, they insist, the view
that the universe is not 'continuous' but 'discretes-in-contact' is no better than the view that there are 'many'
(and not 'one') and a void. For (suppose that the universe is discretes-in-contact. Then), if it is divisible
through and through, there is no 'one', and therefore no 'many' either, but the Whole is void; while to maintain
that it is divisible at some points, but not at others, looks like an arbitrary fiction. For up to what limit is it
divisible? And for what reason is part of the Whole indivisible, i.e. a plenum, and part divided? Further, they
maintain, it is equally necessary to deny the existence of motion.

Reasoning in this way, therefore, they were led to transcend sense-perception, and to disregard it on the
ground that 'one ought to follow the argument': and so they assert that the universe is 'one' and immovable.
Some of them add that it is 'infinite', since the limit (if it had one) would be a limit against the void.

There were, then, certain thinkers who, for the reasons we have stated, enunciated views of this kind as their
theory of The Truth'.... Moreover, although these opinions appear to follow logically in a dialectical
discussion, yet to believe them seems next door to madness when one considers the facts. For indeed no
lunatic seems to be so far out of his senses as to suppose that fire and ice are 'one': it is only between what is
right and what seems right from habit, that some people are mad enough to see no difference.

Leucippus, however, thought he had a theory which harmonized with sense-perception and would not
abolish either coming-to-be and passing-away or motion and the multiplicity of things. He made these
concessions to the facts of perception: on the other hand, he conceded to the Monists that there could be no
motion without a void. The result is a theory which he states as follows: 'The void is a "not being", and no
part of "what is" is a "not-being"; for what "is" in the strict sense of the term is an absolute plenum. This
plenum, however, is not "one": on the contrary, it is a many" infinite in number and invisible owing to the
minuteness of their bulk. The "many" move in the void (for there is a void): and by coming together they
produce "coming to-be", while by separating they produce "passing-away". Moreover, they act and suffer
action wherever they chance to be in contact (for there they are not "one"), and they generate by being put
together and becoming intertwined. From the genuinely-one, on the other hand, there never could have
come-to-be a multiplicity, nor from the genuinely-many a "one": that is impossible. But' (just as
Empedocles and some of the other philosophers say that things suffer action through their pores, so) 'all
"alteration" and all "passion" take place in the way that has been explained: breaking-up (i.e. passing-away)
is effected by means of the void, and so too is growth-solids creeping in to fill the void places.' Empedocles
too is practically bound to adopt the same theory as Leucippus. For he must say that there are certain solids
which, however, are indivisible-unless there are continuous pores all through the body. But this last
alternative is impossible: for then there will be nothing solid in the body (nothing beside the pores) but all of
it will be void. It is necessary, therefore, for his 'contiguous discretes' to be indivisible, while the intervals
between them-which he calls 'pores'-must be void. But this is precisely Leucippus' theory of action and
passion.

Such, approximately, are the current explanations of the manner in which some things 'act' while others
'suffer action'. And as regards the Atomists, it is not only clear what their explanation is: it is also obvious

8 17

ON GENERATION AND CORRUPTION

that it follows with tolerable consistency from the assumptions they employ. But there is less obvious
consistency in the explanation offered by the other thinkers. It is not clear, for instance, how, on the theory of
Empedocles, there is to be 'passing-away' as well as 'alteration'. For the primary bodies of the Atomists-the
primary constituents of which bodies are composed, and the ultimate elements into which they are
dissolved-are indivisible, differing from one another only in figure. In the philosophy of Empedocles, on the
other hand, it is evident that all the other bodies down to the 'elements' have their coming-to-be and their
passingaway: but it is not clear how the 'elements' themselves, severally in their aggregated masses,
come-to-be and pass-away. Nor is it possible for Empedocles to explain how they do so, since he does not
assert that Fire too (and similarly every one of his other 'elements') possesses 'elementary constituents' of
itself.

Such an assertion would commit him to doctrines like those which Plato has set forth in the Timaeus. For
although both Plato and Leucippus postulate elementary constituents that are indivisible and distinctively
characterized by figures, there is this great difference between the two theories: the 'indivisibles' of Leucippus
(i) are solids, while those of Plato are planes, and (ii) are characterized by an infinite variety of figures, while
the characterizing figures employed by Plato are limited in number. Thus the 'comings-to-be' and the
'dissociations' result from the 'indivisibles' (a) according to Leucippus through the void and through contact
(for it is at the point of contact that each of the composite bodies is divisible), but (b) according to Plato in
virtue of contact alone, since he denies there is a void.

Now we have discussed 'indivisible planes' in the preceding treatise.' But with regard to the assumption of
'indivisible solids', although we must not now enter upon a detailed study of its consequences, the following
criticisms fall within the compass of a short digression: i. The Atomists are committed to the view that every
'indivisible' is incapable alike of receiving a sensible property (for nothing can 'suffer action' except through
the void) and of producing one-no 'indivisible' can be, e.g. either hard or cold. Yet it is surely a paradox that
an exception is made of 'the hot'-'the hot' being assigned as peculiar to the spherical figure: for, that being so,
its 'contrary' also ('the cold') is bound to belong to another of the figures. If, however, these properties (heat
and cold) do belong to the 'indivisibles', it is a further paradox that they should not possess heaviness and
lightness, and hardness and softness. And yet Democritus says 'the more any indivisible exceeds, the heavier
it is'-to which we must clearly add 'and the hotter it is'. But if that is their character, it is impossible they
should not be affected by one another: the 'slightly-hot indivisible', e.g. will inevitably suffer action from one
which far exceeds it in heat. Again, if any 'indivisible' is 'hard', there must also be one which is 'soft': but 'the
soft' derives its very name from the fact that it suffers a certain action-for 'soft' is that which yields to
pressure.

II. But further, not only is it paradoxical (i) that no property except figure should belong to the 'indivisibles':
it is also paradoxical (ii) that, if other properties do belong to them, one only of these additional properties
should attach to each-e.g. that this 'indivisible' should be cold and that 'indivisible' hot. For, on that
supposition, their substance would not even be uniform. And it is equally impossible (iii) that more than one
of these additional properties should belong to the single 'indivisible'. For, being indivisible, it will possess
these properties in the same point-so that, if it 'suffers action' by being chilled, it will also, qua chilled, 'act' or
'suffer action' in some other way. And the same line of argument applies to all the other properties too: for the
difficulty we have just raised confronts, as a necessary consequence, all who advocate 'indivisibles' (whether
solids or planes), since their 'indivisibles' cannot become either 'rarer' or 'derser' inasmuch as there is no void
in them.

III. It is a further paradox that there should be small 'indivisibles', but not large ones. For it is natural enough,
from the ordinary point of view, that the larger bodies should be more liable to fracture than the small ones,
since they (viz. the large bodies) are easily broken up because they collide with many other bodies. But why
should indivisibility as such be the property of small, rather than of large, bodies?

ON GENERATION AND CORRUPTION

IV. Again, is the substance of all those solids uniform, or do they fall into sets which differ from one
another-as if, e.g. some of them, in their aggregated bulk, were 'fiery', others earthy'? For (i) if all of them are
uniform in substance, what is it that separated one from another? Or why, when they come into contact, do
they not coalesce into one, as drops of water run together when drop touches drop (for the two cases are
precisely parallel)? On the other hand (ii) if they fall into differing sets, how are these characterized? It is
clear, too, that these, rather than the 'figures', ought to be postulated as 'original reals', i.e. causes from which
the phenomena result. Moreover, if they differed in substance, they would both act and suffer action on
coming into reciprocal contact.

V. Again, what is it which sets them moving? For if their 'mover' is other than themselves, they are such as to
'suffer action'. If, on the other hand, each of them sets itself in motion, either (a) it will be divisible
('imparting motion' qua this, 'being moved' qua that), or (b) contrary properties will attach to it in the same
respect-i.e. 'matter' will be identical in-potentiality as well as numerically-identical.

As to the thinkers who explain modification of property through the movement facilitated by the pores, if this
is supposed to occur notwithstanding the fact that the pores are filled, their postulate of pores is superfluous.
For if the whole body suffers action under these conditions, it would suffer action in the same way even if it
had no pores but were just its own continuous self. Moreover, how can their account of 'vision through a
medium' be correct? It is impossible for (the visual ray) to penetrate the transparent bodies at their 'contacts';
and impossible for it to pass through their pores if every pore be full. For how will that differ from having no
pores at all? The body will be uniformly 'full' throughout. But, further, even if these passages, though they
must contain bodies, are 'void', the same consequence will follow once more. And if they are 'too minute to
admit any body', it is absurd to suppose there is a 'minute' void and yet to deny the existence of a 'big' one (no
matter how small the 'big' may be), or to imagine 'the void' means anything else than a body's place-whence
it clearly follows that to every body there will correspond a void of equal cubic capacity.

As a general criticism we must urge that to postulate pores is superfluous. For if the agent produces no effect
by touching the patient, neither will it produce any by passing through its pores. On the other hand, if it acts
by contact, then-even without pores-some things will 'suffer action' and others will 'act', provided they are
by nature adapted for reciprocal action and passion. Our arguments have shown that it is either false or futile
to advocate pores in the sense in which some thinkers conceive them. But since bodies are divisible through
and through, the postulate of pores is ridiculous: for, qua divisible, a body can fall into separate parts.

Let explain the way in which things in fact possess the power of generating, and of acting and suffering
action: and let us start from the principle we have often enunciated. For, assuming the distinction between (a)
that which is potentially and (b) that which is actually such-and-such, it is the nature of the first, precisely in
so far as it is what it is, to suffer action through and through, not merely to be susceptible in some parts while
insusceptible in others. But its susceptibility varies in degree, according as it is more or less; such-and such,
and one would be more justified in speaking of 'pores' in this connexion: for instance, in the metals there are
veins of 'the susceptible' stretching continuously through the substance.

So long, indeed, as any body is naturally coherent and one, it is insusceptible. So, too, bodies are
insusceptible so long as they are not in contact either with one another or with other bodies which are by
nature such as to act and suffer action. (To illustrate my meaning: Fire heats not only when in contact, but
also from a distance. For the fire heats the air, and the air-being by nature such as both to act and suffer
action-heats the body.) But the supposition that a body is 'susceptible in some parts, but insusceptible in
others' (is only possible for those who hold an erroneous view concerning the divisibility of magnitudes. For
us) the following account results from the distinctions we established at the beginning. For (i) if magnitudes

9 19

ON GENERATION AND CORRUPTION

are not divisible through and through-if, on the contrary, there are indivisible solids or planes-then indeed no
body would be susceptible through and through :but neither would any be continuous. Since, however, (ii)
this is false, i.e. since every body is divisible, there is no difference between 'having been divided into parts
which remain in contact' and 'being divisible'. For if a body 'can be separated at the contacts' (as some
thinkers express it), then, even though it has not yet been divided, it will be in a state of dividedness-since, as
it can be divided, nothing inconceivable results. And (iii) the suposition is open to this general objection-it is
a paradox that 'passion' should occur in this manner only, viz. by the bodies being split. For this theory
abolishes 'alteration': but we see the same body liquid at one time and solid at another, without losing its
continuity. It has suffered this change not by 'division' and composition', nor yet by 'turning' and 'intercontact'
as Democritus asserts; for it has passed from the liquid to the solid state without any change of 'grouping' or
'position' in the constituents of its substance. Nor are there contained within it those 'hard' (i.e. congealed)
particles 'indivisible in their bulk': on the contrary, it is liquid- and again, solid and congealed-uniformly all
through. This theory, it must be added, makes growth and diminution impossible also. For if there is to be
opposition (instead of the growing thing having changed as a whole, either by the admixture of something or
by its own transformation), increase of size will not have resulted in any and every part.

So much, then, to establish that things generate and are generated, act and suffer action, reciprocally; and to
distinguish the way in which these processes can occur from the (impossible) way in which some thinkers say
they occur.

But we have still to explain 'combination', for that was the third of the subjects we originally proposed to
discuss. Our explanation will proceed on the same method as before. We must inquire: What is 'combination',
and what is that which can 'combine'? Of what things, and under what conditions, is 'combination' a property?
And, further, does 'combination' exist in fact, or is it false to assert its existence?

For, according to some thinkers, it is impossible for one thing to be combined with another. They argue that
(i) if both the 'combined' constituents persist unaltered, they are no more 'combined' now than they were
before, but are in the same condition: while (ii) if one has been destroyed, the constituents have not been
'combined'-on the contrary, one constituent is and the other is not, whereas 'combination' demands
uniformity of condition in them both: and on the same principle (iii) even if both the combining constituents
have been destroyed as the result of their coalescence, they cannot 'have been combined' since they have no
being at all.

What we have in this argument is, it would seem, a demand for the precise distinction of 'combination' from
coming-to-be and passingaway (for it is obvious that 'combination', if it exists, must differ from these
processes) and for the precise distinction of the 'combinable' from that which is such as to come-to-be and
pass-away. As soon, therefore, as these distinctions are clear, the difficulties raised by the argument would
be solved.

Now (i) we do not speak of the wood as 'combined' with the fire, nor of its burning as a 'combining' either of
its particles with one another or of itself with the fire: what we say is that 'the fire is coming-to-be, but the
wood is 'passing-away'. Similarly, we speak neither (ii) of the food as 'combining' with the body, nor (iii) of
the shape as 'combining' with the wax and thus fashioning the lump. Nor can body 'combine' with white, nor
(to generalize) 'properties' and 'states' with 'things': for we see them persisting unaltered. But again (iv) white
and knowledge cannot be 'combined' either, nor any other of the 'adjectivals'. (Indeed, this is a blemish in the
theory of those who assert that 'once upon a time all things were together and combined'. For not everything
can 'combine' with everything. On the contrary, both of the constituents that are combined in the compound
must originally have existed in separation: but no property can have separate existence.)

10 20

ON GENERATION AND CORRUPTION

Since, however, some things are-potentially while others are-actually, the constituents combined in a
compound can 'be' in a sense and yet 'not-be'. The compound may he-actually other than the constituents
from which it has resulted; nevertheless each of them may still he-potentially what it was before they were
combined, and both of them may survive undestroyed. (For this was the difficulty that emerged in the
previous argument: and it is evident that the combining constituents not only coalesce, having formerly
existed in separation, but also can again be separated out from the compound.) The constituents, therefore,
neither (a) persist actually, as 'body' and 'white' persist: nor (b) are they destroyed (either one of them or
both), for their 'power of action' is preserved. Hence these difficulties may be dismissed: but the problem
immediately connected with them-whether combination is something relative to perception' must be set out
and discussed.

When the combining constituents have been divided into parts so small, and have been juxtaposed in such a
manner, that perception fails to discriminate them one from another, have they then 'been combined Or ought
we to say 'No, not until any and every part of one constituent is juxtaposed to a part of the other'? The term,
no doubt, is applied in the former sense: we speak, e.g. of wheat having been 'combined' with barley when
each grain of the one is juxtaposed to a grain of the other. But every body is divisible and therefore, since
body 'combined' with body is uniform in texture throughout, any and every part of each constituent ought to
be juxtaposed to a part of the other.

No body, however, can be divided into its 'least' parts: and 'composition' is not identical with 'combination',
but other than it. From these premises it clearly follows (i) that so long as the constituents are preserved in
small particles, we must not speak of them as 'combined'. (For this will be a 'composition' instead of a
'blending' or 'combination': nor will every portion of the resultant exhibit the same ratio between its
constituents as the whole. But we maintain that, if 'combination' has taken place, the compound must be
uniform in texture throughout-any part of such a compound being the same as the whole, just as any part of
water is water: whereas, if 'combination' is 'composition of the small particles', nothing of the kind will
happen. On the contrary, the constituents will only be 'combined' relatively to perception: and the same thing
will be 'combined' to one percipient, if his sight is not sharp, (but not to another,) while to the eye of Lynceus
nothing will be 'combined'.) It clearly follows (ii) that we must not speak of the constituents as 'combined in
virtue of a division such that any and every part of each is juxtaposed to a part of the other: for it is
impossible for them to be thus divided. Either, then, there is no 'combination', or we have still to explain the
manner in which it can take place.

Now, as we maintain, some things are such as to act and others such as to suffer action from them. Moreover,
some things-viz. those Which have the same matter- 'reciprocate', i.e. are such as to act upon one another and
to suffer action from one another; while other things, viz. agents which have not the same matter as their
patients, act without themselves suffering action. Such agents cannot 'combine'-that is why neither the art of
healing nor health produces health by 'combining' with the bodies of the patients. Amongst those things,
however, which are reciprocally active and passive, some are easily-divisible. Now (i) if a great quantity (or
a large bulk) of one of these easily-divisible 'reciprocating' materials be brought together with a little (or with
a small piece) of another, the effect produced is not 'combination', but increase of the dominant: for the other
material is transformed into the dominant. (That is why a drop of wine does not 'combine' with ten thousand
gallons of water: for its form is dissolved, and it is changed so as to merge in the total volume of water.) On
the other hand (ii) when there is a certain equilibrium between their 'powers of action', then each of them
changes out of its own nature towards the dominant: yet neither becomes the other, but both become an
intermediate with properties common to both.

Thus it is clear that only those agents are 'combinable' which involve a contrariety-for these are such as to
suffer action reciprocally. And, further, they combine more freely if small pieces of each of them are
juxtaposed. For in that condition they change one another more easily and more quickly; whereas this effect
takes a long time when agent and patient are present in bulk.

10 21

ON GENERATION AND CORRUPTION

Hence, amongst the divisible susceptible materials, those whose shape is readily adaptable have a tendency to
combine: for they are easily divided into small particles, since that is precisely what 'being readily adaptable
in shape' implies. For instance, liquids are the most 'combinable' of all bodies-because, of all divisible
materials, the liquid is most readily adaptable in shape, unless it be viscous. Viscous liquids, it is true,
produce no effect except to increase the volume and bulk. But when one of the constituents is alone
susceptible-or superlatively susceptible, the other being susceptible in a very slight degree-the compound
resulting from their combination is either no greater in volume or only a little greater. This is what happens
when tin is combined with bronze. For some things display a hesitating and ambiguous attitude towards one
another-showing a slight tendency to combine and also an inclination to behave as 'receptive matter' and
'form' respectively. The behaviour of these metals is a case in point. For the tin almost vanishes, behaving as
if it were an immaterial property of the bronze: having been combined, it disappears, leaving no trace except
the colour it has imparted to the bronze. The same phenomenon occurs in other instances too.

It is clear, then, from the foregoing account, that 'combination' occurs, what it is, to what it is due, and what
kind of thing is 'combinable'. The phenomenon depends upon the fact that some things are such as to be (a)
reciprocally susceptible and (b) readily adaptable in shape, i.e. easily divisible. For such things can be
'combined' without its being necessary either that they should have been destroyed or that they should survive
absolutely unaltered: and their 'combination' need not be a 'composition', nor merely 'relative to perception'.
On the contrary: anything is 'combinable' which, being readily adaptable in shape, is such as to suffer action
and to act; and it is 'combinable with' another thing similarly characterized (for the 'combinable' is relative to
the 'combinable'); and 'combination' is unification of the 'combinables', resulting from their 'alteration'.

Book II

WE have explained under what conditions 'combination', 'contact', and 'action-passion' are attributable to the
things which undergo natural change. Further, we have discussed 'unqualified' coming-to-be and
passing-away, and explained under what conditions they are predicable, of what subject, and owing to what
cause. Similarly, we have also discussed 'alteration', and explained what 'altering' is and how it differs from
coming-to-be and passing-away. But we have still to investigate the so-called 'elements' of bodies.

For the complex substances whose formation and maintenance are due to natural processes all presuppose the
perceptible bodies as the condition of their coming-to-be and passing-away: but philosophers disagree in
regard to the matter which underlies these perceptible bodies. Some maintain it is single, supposing it to be,
e.g. Air or Fire, or an 'intermediate' between these two (but still a body with a separate existence). Others, on
the contrary, postulate two or more materials-ascribing to their 'association' and 'dissociation', or to their
'alteration', the coming-to-be and passing-away of things. (Some, for instance, postulate Fire and Earth:
some add Air, making three: and some, like Empedocles, reckon Water as well, thus postulating four.)

Now we may agree that the primary materials, whose change (whether it be 'association and dissociation' or a
process of another kind) results in coming-to-be and passingaway, are rightly described as 'originative
sources, i.e. elements'. But (i) those thinkers are in error who postulate, beside the bodies we have mentioned,
a single matter-and that corporeal and separable matter. For this 'body' of theirs cannot possibly exist without
a 'perceptible contrariety': this 'Boundless', which some thinkers identify with the 'original real', must be
either light or heavy, either cold or hot. And (ii) what Plato has written in the Timaeus is not based on any
precisely-articulated conception. For he has not stated clearly whether his 'Omnirecipient" exists in
separation from the 'elements'; nor does he make any use of it. He says, indeed, that it is a substratum prior to
the so-called 'elements-underlying them, as gold underlies the things that are fashioned of gold. (And yet
this comparison, if thus expressed, is itself open to criticism. Things which come-to-be and pass-away

Book II 22

ON GENERATION AND CORRUPTION

cannot be called by the name of the material out of which they have come-tobe: it is only the results of
'alteration' which retain the name of the substratum whose 'alterations' they are. However, he actually says'
that the truest account is to affirm that each of them is "gold"'.) Nevertheless he carries his analysis of the
'elements'-solids though they are-back to 'planes', and it is impossible for 'the Nurse' (i.e. the primary matter)
to be identical with 'the planes'.

Our own doctrine is that although there is a matter of the perceptible bodies (a matter out of which the
so-called 'elements' come-to-be), it has no separate existence, but is always bound up with a contrariety. A
more precise account of these presuppositions has been given in another work': we must, however, give a
detailed explanation of the primary bodies as well, since they too are similarly derived from the matter. We
must reckon as an 'originative source' and as 'primary' the matter which underlies, though it is inseparable
from, the contrary qualities: for the hot' is not matter for 'the cold' nor 'the cold' for 'the hot', but the
substratum is matter for them both. We therefore have to recognize three 'originative sources': firstly that
which potentially perceptible body, secondly the contrarieties (I mean, e.g. heat and cold), and thirdly Fire,
Water, and the like. Only 'thirdly', however: for these bodies change into one another (they are not immutable
as Empedocles and other thinkers assert, since 'alteration' would then have been impossible), whereas the
contrarieties do not change.

Nevertheless, even so the question remains: What sorts of contrarieties, and how many of them, are to be
accounted 'originative sources' of body? For all the other thinkers assume and use them without explaining
why they are these or why they are just so many.

Since, then, we are looking for 'originative sources' of perceptible body; and since 'perceptible' is equivalent
to 'tangible', and 'tangible' is that of which the perception is touch; it is clear that not all the contrarieties
constitute 'forms' and 'originative sources' of body, but only those which correspond to touch. For it is in
accordance with a contrariety-a contrariety, moreover, of tangible qualities-that the primary bodies are
differentiated. That is why neither whiteness (and blackness), nor sweetness (and bitterness), nor (similarly)
any quality belonging to the other perceptible contrarieties either, constitutes an 'element'. And yet vision is
prior to touch, so that its object also is prior to the object of touch. The object of vision, however, is a quality
of tangible body not qua tangible, but qua something else-qua something which may well be naturally prior
to the object of touch.

Accordingly, we must segregate the tangible differences and contrarieties, and distinguish which amongst
them are primary. Contrarieties correlative to touch are the following: hot-cold, dry-moist, heavy-light,
hard-soft, viscous-brittle, rough-smooth, coarse-fine. Of these (i) heavy and light are neither active nor
susceptible. Things are not called 'heavy' and 'light' because they act upon, or suffer action from, other things.
But the 'elements' must be reciprocally active and susceptible, since they 'combine' and are transformed into
one another. On the other hand (ii) hot and cold, and dry and moist, are terms, of which the first pair implies
power to act and the second pair susceptibility. 'Hot' is that which 'associates' things of the same kind (for
'dissociating', which people attribute to Fire as its function, is 'associating' things of the same class, since its
effect is to eliminate what is foreign), while 'cold' is that which brings together, i.e. 'associates', homogeneous
and heterogeneous things alike. And moise is that which, being readily adaptable in shape, is not
determinable by any limit of its own: while 'dry' is that which is readily determinable by its own limit, but not
readily adaptable in shape.

From moist and dry are derived (iii) the fine and coarse, viscous and brittle, hard and soft, and the remaining
tangible differences. For (a) since the moist has no determinate shape, but is readily adaptable and follows the
outline of that which is in contact with it, it is characteristic of it to be 'such as to fill up'. Now 'the fine' is

2 23

ON GENERATION AND CORRUPTION

'such as to fill up'. For the fine' consists of subtle particles; but that which consists of small particles is 'such
as to fill up', inasmuch as it is in contact whole with whole- and 'the fine' exhibits this character in a
superlative degree. Hence it is evident that the fine derives from the moist, while the coarse derives from the
dry. Again (b) the viscous' derives from the moist: for 'the viscous' (e.g. oil) is a 'moist' modified in a certain
way. 'The brittle', on the other hand, derives from the dry: for 'brittle' is that which is completely dry-so
completely, that its solidification has actually been due to failure of moisture. Further (c) 'the soft' derives
from the moist. For 'soft' is that which yields to pressure by retiring into itself, though it does not yield by
total displacement as the moist does-which explains why the moist is not 'soft', although 'the soft' derives
from the moist. 'The hard', on the other hand, derives from the dry: for 'hard' is that which is solidified, and
the solidified is dry.

The terms 'dry' and 'moist' have more senses than one. For 'the damp', as well as the moist, is opposed to the
dry: and again 'the solidified', as well as the dry, is opposed to the moist. But all these qualities derive from
the dry and moist we mentioned first.' For (i) the dry is opposed to the damp: i.e. 'damp' is that which has
foreign moisture on its surface ('sodden' being that which is penetrated to its core), while 'dry' is that which
has lost foreign moisture. Hence it is evident that the damp will derive from the moist, and 'the dry' which is
opposed to it will derive from the primary dry. Again (ii) the 'moist' and the solidified derive in the same way
from the primary pair. For 'moist' is that which contains moisture of its-own deep within it ('sodden' being
that which is deeply penetrated by foreign mosture), whereas 'solidigied' is that which has lost this inner
moisture. Hence these too derive from the primary pair, the 'solidified' from the dry and the 'solidified' from
the dry the 'liquefiable' from the moist.

It is clear, then, that all the other differences reduce to the first four, but that these admit of no further
reduction. For the hot is not essentially moist or dry, nor the moist essentially hot or cold: nor are the cold
and the dry derivative forms, either of one another or of the hot and the moist. Hence these must be four.

The elementary qualities are four, and any four terms can be combined in six couples. Contraries, however,
refuse to be coupled: for it is impossible for the same thing to be hot and cold, or moist and dry. Hence it is
evident that the 'couplings' of the elementary qualities will be four: hot with dry and moist with hot, and again
cold with dry and cold with moist. And these four couples have attached themselves to the apparently 'simple'
bodies (Fire, Air, Water, and Earth) in a manner consonant with theory. For Fire is hot and dry, whereas Air
is hot and moist (Air being a sort of aqueous vapour); and Water is cold and moist, while Earth is cold and
dry. Thus the differences are reasonably distributed among the primary bodies, and the number of the latter is
consonant with theory. For all who make the simple bodies 'elements' postulate either one, or two, or three, or
four. Now (i) those who assert there is one only, and then generate everything else by condensation and
rarefaction, are in effect making their 'originative sources' two, viz. the rare and the dense, or rather the hot
and the cold: for it is these which are the moulding forces, while the 'one' underlies them as a 'matter'. But (ii)
those who postulate two from the start-as Parmenides postulated Fire and Earth-make the intermediates (e.g.
Air and Water) blends of these. The same course is followed (iii) by those who advocate three. (We may
compare what Plato does in Me Divisions': for he makes 'the middle' a blend.) Indeed, there is practically no
difference between those who postulate two and those who postulate three, except that the former split the
middle 'element' into two, while the latter treat it as only one. But (iv) some advocate four from the start, e.g.
Empedocles: yet he too draws them together so as to reduce them to the two, for he opposes all the others to
Fire.

In fact, however, fire and air, and each of the bodies we have mentioned, are not simple, but blended. The
'simple' bodies are indeed similar in nature to them, but not identical with them. Thus the 'simple' body
corresponding to fire is 'such-as-fire, not fire: that which corresponds to air is 'such- as-air': and so on with

3 24

ON GENERATION AND CORRUPTION

the rest of them. But fire is an excess of heat, just as ice is an excess of cold. For freezing and boiling are
excesses of heat and cold respectively. Assuming, therefore, that ice is a freezing of moist and cold, fire
analogously will be a boiling of dry and hot: a fact, by the way, which explains why nothing comes-to-be
either out of ice or out of fire.

The 'simple' bodies, since they are four, fall into two pairs which belong to the two regions, each to each: for
Fire and Air are forms of the body moving towards the 'limit', while Earth and Water are forms of the body
which moves towards the 'centre'. Fire and Earth, moreover, are extremes and purest: Water and Air, on the
contrary are intermediates and more like blends. And, further, the members of either pair are contrary to those
of the other, Water being contrary to Fire and Earth to Air; for the qualities constituting Water and Earth are
contrary to those that constitute Fire and Air. Nevertheless, since they are four, each of them is characterized
par excellence a single quality: Earth by dry rather than by cold, Water by cold rather than by moist, Air by
moist rather than by hot, and Fire by hot rather than by dry.

It has been established before' that the coming-to-be of the 'simple' bodies is reciprocal. At the same time, it
is manifest, even on the evidence of perception, that they do come-to-be: for otherwise there would not have
been 'alteration, since 'alteration' is change in respect to the qualities of the objects of touch. Consequently,
we must explain (i) what is the manner of their reciprocal transformation, and (ii) whether every one of them
can come to-be out of every one-or whether some can do so, but not others.

Now it is evident that all of them are by nature such as to change into one another: for coming-to-be is a
change into contraries and out of contraries, and the 'elements' all involve a contrariety in their mutual
relations because their distinctive qualities are contrary. For in some of them both qualities are contrary-e.g.
in Fire and Water, the first of these being dry and hot, and the second moist and cold: while in others one of
the qualities (though only one) is contrary-e.g. in Air and Water, the first being moist and hot, and the second
moist and cold. It is evident, therefore, if we consider them in general, that every one is by nature such as to
come-to-be out of every one: and when we come to consider them severally, it is not difficult to see the
manner in which their transformation is effected. For, though all will result from all, both the speed and the
facility of their conversion will differ in degree.

Thus (i) the process of conversion will be quick between those which have interchangeable 'complementary
factors', but slow between those which have none. The reason is that it is easier for a single thing to change
than for many. Air, e.g. will result from Fire if a single quality changes: for Fire, as we saw, is hot and dry
while Air is hot and moist, so that there will be Air if the dry be overcome by the moist. Again, Water will
result from Air if the hot be overcome by the cold: for Air, as we saw, is hot and moist while Water is cold
and moist, so that, if the hot changes, there will be Water. So too, in the same manner, Earth will result from
Water and Fire from Earth, since the two 'elements' in both these couples have interchangeable
'complementary factors'. For Water is moist and cold while Earth is cold and dry-so that, if the moist be
overcome, there will be Earth: and again, since Fire is dry and hot while Earth is cold and dry, Fire will result
from Earth if the cold pass-away.

It is evident, therefore, that the coming-to-be of the 'simple' bodies will be cyclical; and that this cyclical
method of transformation is the easiest, because the consecutive 'elements' contain interchangeable
'complementary factors'. On the other hand (ii) the transformation of Fire into Water and of Air into Earth,
and again of Water and Earth into Fire and Air respectively, though possible, is more difficult because it
involves the change of more qualities. For if Fire is to result from Water, both the cold and the moist must
pass-away: and again, both the cold and the dry must pass-away if Air is to result from Earth. So' too, if
Water and Earth are to result from Fire and Air respectively-both qualities must change.

4 25

ON GENERATION AND CORRUPTION

This second method of coming-to-be, then, takes a longer time. But (hi) if one quality in each of two
'elements' pass-away, the transformation, though easier, is not reciprocal. Still, from Fire plus Water there
will result Earth and Air, and from Air plus Earth Fire and Water. For there will be Air, when the cold of the
Water and the dry of the Fire have passed-away (since the hot of the latter and the moist of the former are
left): whereas, when the hot of the Fire and the moist of the Water have passed-away, there will be Earth,
owing to the survival of the dry of the Fire and the cold of the Water. So, too, in the same Way, Fire and
Water will result from Air plus Earth. For there will be Water, when the hot of the Air and the dry of the
Earth have passed-away (since the moist of the former and the cold of the latter are left): whereas, when the
moist of the Air and the cold of the Earth have passed-away, there will be Fire, owing to the survival of the
hot of the Air and the dry of the Earth-qualities essentially constitutive of Fire. Moreover, this mode of Fire's
coming-to-be is confirmed by perception. For flame is par excellence Fire: but flame is burning smoke, and
smoke consists of Air and Earth.

No transformation, however, into any of the 'simple' bodies can result from the passingaway of one
elementary quality in each of two 'elements' when they are taken in their consecutive order, because either
identical or contrary qualities are left in the pair: but no 'simple' body can be formed either out of identical, or
out of contrary, qualities. Thus no 'simple' body would result, if the dry of Fire and the moist of Air were to
pass- aw ay: for the hot is left in both. On the other hand, if the hot pass-away out both, the contraries-dry
and moist- are left. A similar result will occur in all the others too: for all the consecutive 'elements' contain
one identical, and one contrary, quality. Hence, too, it clearly follows that, when one of the consecutive
'elements' is transformed into one, the coming-to-be is effected by the passing-away of a single quality:
whereas, when two of them are transformed into a third, more than one quality must have passedaway.

We have stated that all the 'elements' come-to-be out of any one of them; and we have explained the manner
in which their mutual conversion takes place. Let us nevertheless supplement our theory by the following
speculations concerning them.

If Water, Air, and the like are a 'matter' of which the natural bodies consist, as some thinkers in fact believe,
these 'elements' must be either one, or two, or more. Now they cannot all of them be one-they cannot, e.g. all
be Air or Water or Fire or Earth-because 'Change is into contraries'. For if they all were Air, then (assuming
Air to persist) there will be 'alteration' instead of coming-to-be. Besides, nobody supposes a single 'element'
to persist, as the basis of all, in such a way that it is Water as well as Air (or any other 'element') at the same
time. So there will be a certain contrariety, i.e. a differentiating quality: and the other member of this
contrariety, e.g. heat, will belong to some other 'element', e.g. to Fire. But Fire will certainly not be 'hot Air'.
For a change of that kind (a) is 'alteration', and (b) is not what is observed. Moreover (c) if Air is again to
result out of the Fire, it will do so by the conversion of the hot into its contrary: this contrary, therefore, will
belong to Air, and Air will be a cold something: hence it is impossible for Fire to be 'hot Air', since in that
case the same thing will be simultaneously hot and cold. Both Fire and Air, therefore, will be something else
which is the same; i.e. there will be some 'matter', other than either, common to both.

The same argument applies to all the 'elements', proving that there is no single one of them out of which they
all originate. But neither is there, beside these four, some other body from which they originate-a something
intermediate, e.g. between Air and Water (coarser than Air, but finer than Water), or between Air and Fire
(coarser than Fire, but finer than Air). For the supposed 'intermediate' will be Air and Fire when a pair of
contrasted qualities is added to it: but, since one of every two contrary qualities is a 'privation', the
'intermediate' never can exist-as some thinkers assert the 'Boundless' or the 'Environing' exists-in isolation. It
is, therefore, equally and indifferently any one of the 'elements', or else it is nothing.

ON GENERATION AND CORRUPTION

Since, then, there is nothing-at least, nothing perceptible-prior to these, they must be all. That being so,
either they must always persist and not be transformable into one another: or they must undergo
transformation-either all of them, or some only (as Plato wrote in the Timacus).' Now it has been proved
before that they must undergo reciprocal transformation. It has also been proved that the speed with which
they come-to-be, one out of another, is not uniform-since the process of reciprocal transformation is
relatively quick between the 'elements' with a 'complementary factor', but relatively slow between those
which possess no such factor. Assuming, then, that the contrariety, in respect to which they are transformed,
is one, the elements' will inevitably be two: for it is 'matter' that is the 'mean' between the two contraries, and
matter is imperceptible and inseparable from them. Since, however, the 'elements' are seen to be more than
two, the contrarieties must at the least be two. But the contrarieties being two, the 'elements' must be four (as
they evidently are) and cannot be three: for the couplings' are four, since, though six are possible, the two in
which the qualities are contrary to one another cannot occur.

These subjects have been discussed before:' but the following arguments will make it clear that, since the
'elements' are transformed into one another, it is impossible for any one of them-whether it be at the end or in
the middle-to be an 'originative source' of the rest. There can be no such 'originative element' at the ends: for
all of them would then be Fire or Earth, and this theory amounts to the assertion that all things are made of
Fire or Earth. Nor can a 'middle-element' be such an originative source'-as some thinkers suppose that Air is
transformed both into Fire and into Water, and Water both into Air and into Earth, while the 'end-elements'
are not further transformed into one another. For the process must come to a stop, and cannot continue ad
infinitum in a straight line in either direction, since otherwise an infinite number of contrarieties would attach
to the single 'element'. Let E stand for Earth, W for Water, A for Air, and F for Fire. Then (i) since A is
transformed into F and W, there will be a contrariety belonging to A F. Let these contraries be whiteness and
blackness. Again (ii) since A is transformed into W, there will be another contrariety: for W is not the same
as F. Let this second contrariety be dryness and moistness, D being dryness and M moistness. Now if, when
A is transformed into W, the 'white' persists, Water will be moist and white: but if it does not persist, Water
will be black since change is into contraries. Water, therefore, must be either white or black. Let it then be the
first. On similar grounds, therefore, D (dryness) will also belong to F. Consequently F (Fire) as well as Air
will be able to be transformed into Water: for it has qualities contrary to those of Water, since Fire was first
taken to be black and then to be dry, while Water was moist and then showed itself white. Thus it is evident
that all the 'elements' will be able to be transformed out of one another; and that, in the instances we have
taken, E (Earth) also will contain the remaining two 'complementary factors', viz. the black and the moist (for
these have not yet been coupled).

We have dealt with this last topic before the thesis we set out to prove. That thesis-viz. that the process
cannot continue ad infinitum-will be clear from the following considerations. If Fire (which is represented by
F) is not to revert, but is to be transformed in turn into some other 'element' (e.g. into Q), a new contrariety,
other than those mentioned, will belong to Fire and Q: for it has been assumed that Q is not the same as any
of the four, E W A and F. Let K, then, belong to F and Y to Q. Then K will belong to all four, E W A and F:
for they are transformed into one another. This last point, however, we may admit, has not yet been proved:
but at any rate it is clear that if Q is to be transformed in turn into yet another 'element', yet another
contrariety will belong not only to Q but also to F (Fire). And, similarly, every addition of a new 'element'
will carry with it the attachment of a new contrariety to the preceding elements'. Consequently, if the
'elements' are infinitely many, there will also belong to the single 'element' an infinite number of contrarieties.
But if that be so, it will be impossible to define any 'element': impossible also for any to come-to-be. For if
one is to result from another, it will have to pass through such a vast number of contrarieties-and indeed even
more than any determinate number. Consequently (i) into some 'elements' transformation will never be
effected-viz. if the intermediates are infinite in number, as they must be if the 'elements' are infinitely many:
further (ii) there will not even be a transformation of Air into Fire, if the contrarieties are infinitely many:
moreover (iii) all the 'elements' become one. For all the contrarieties of the 'elements' above F must belong to
those below F, and vice versa: hence they will all be one.

5 27

ON GENERATION AND CORRUPTION

As for those who agree with Empedocles that the 'elements' of body are more than one, so that they are not
transformed into one another-one may well wonder in what sense it is open to them to maintain that the
'elements' are comparable. Yet Empedocles says 'For these are all not only equal...'

If it is meant that they are comparable in their amount, all the 'comparables' must possess an identical
something whereby they are measured. If, e.g. one pint of Water yields ten of Air, both are measured by the
same unit; and therefore both were from the first an identical something. On the other hand, suppose (ii) they
are not 'comparable in their amount' in the sense that so-much of the one yields so much of the other, but
comparable in 'power of action (a pint of Water, e.g. having a power of cooling equal to that of ten pints of
Air); even so, they are 'comparable in their amount', though not qua 'amount' but qua Iso-much power'. There
is also (iii) a third possibility. Instead of comparing their powers by the measure of their amount, they might
be compared as terms in a 'correspondence': e.g. 'as x is hot, so correspondingly y is white'. But
'correspondence', though it means equality in the quantum, means similarity in a quale. Thus it is manifestly
absurd that the 'simple' bodies, though they are not transformable, are comparable not merely as
'corresponding', but by a measure of their powers; i.e. that so-much Fire is comparable with many
times-that-amount of Air, as being 'equally' or 'similarly' hot. For the same thing, if it be greater in amount,
will, since it belongs to the same kind, have its ratio correspondingly increased.

A further objection to the theory of Empedocles is that it makes even growth impossible, unless it be increase
by addition. For his Fire increases by Fire: 'And Earth increases its own frame and Ether increases Ether."
These, however, are cases of addition: but it is not by addition that growing things are believed to increase.
And it is far more difficult for him to account for the coming-to-be which occurs in nature. For the things
which come-to-be by natural process all exhibit, in their coming-to-be, a uniformity either absolute or
highly regular: while any exceptions any results which are in accordance neither with the invariable nor with
the general rule are products of chance and luck. Then what is the cause determining that man comes-to-be
from man, that wheat (instead of an olive) comes-to-be from wheat, either invariably or generally? Are we
to say 'Bone comes-to-be if the "elements" be put together in such-and such a manner'? For, according to
his own estatements, nothing comes-to-be from their 'fortuitous consilience', but only from their 'consilience'
in a certain proportion. What, then, is the cause of this proportional consilience? Presumably not Fire or
Earth. But neither is it Love and Strife: for the former is a cause of 'association' only, and the latter only of
'dissociation'. No: the cause in question is the essential nature of each thing-not merely to quote his words) 'a
mingling and a divorce of what has been mingled'. And chance, not proportion, 'is the name given to these
occurrences': for things can be 'mingled' fortuitously.

The cause, therefore, of the coming-to-be of the things which owe their existence to nature is that they are in
such-and-such a determinate condition: and it is this which constitutes, the 'nature' of each thing-a 'nature'
about which he says nothing. What he says, therefore, is no explanation of 'nature'. Moreover, it is this which
is both 'the excellence' of each thing and its 'good': whereas he assigns the whole credit to the 'mingling'.
(And yet the 'elements' at all events are 'dissociated' not by Strife, but by Love: since the 'elements' are by
nature prior to the Deity, and they too are Deities.)

Again, his account of motion is vague. For it is not an adequate explanation to say that Love and Strife set
things moving, unless the very nature of Love is a movement of this kind and the very nature of Strife a
movement of that kind. He ought, then, either to have defined or to have postulated these characteristic
movements, or to have demonstrated them-whether strictly or laxly or in some other fashion. Moreover,
since (a) the 'simple' bodies appear to move 'naturally' as well as by compulsion, i.e. in a manner contrary to
nature (fire, e.g. appears to move upwards without compulsion, though it appears to move by compulsion
downwards); and since (b) what is 'natural' is contrary to that which is due to compulsion, and movement by

6 28

ON GENERATION AND CORRUPTION

compulsion actually occurs; it follows that 'natural movement' can also occur in fact. Is this, then, the
movement that Love sets going? No: for, on the contrary, the 'natural movement' moves Earth downwards
and resembles 'dissociation', and Strife rather than Love is its cause-so that in general, too, Love rather than
Strife would seem to be contrary to nature. And unless Love or Strife is actually setting them in motion, the
'simple' bodies themselves have absolutely no movement or rest. But this is paradoxical: and what is more,
they do in fact obviously move. For though Strife 'dissociated', it was not by Strife that the 'Ether' was borne
upwards. On the contrary, sometimes he attributes its movement to something like chance ('For thus, as it ran,
it happened to meet them then, though often otherwise"), while at other times he says it is the nature of Fire
to be borne upwards, but 'the Ether' (to quote his words) 'sank down upon the Earth with long roots'. With
such statements, too, he combines the assertion that the Order of the World is the same now, in the reign of
Strife, as it was formerly in the reign of Love. What, then, is the 'first mover' of the 'elements'? What causes
their motion? Presumably not Love and Strife: on the contrary, these are causes of a particular motion, if at
least we assume that 'first mover' to be an originative source'.

An additional paradox is that the soul should consist of the 'elements', or that it should be one of them. How
are the soul's 'alterations' to take Place? How, e.g. is the change from being musical to being unmusical, or
how is memory or forgetting, to occur? For clearly, if the soul be Fire, only such modifications will happen to
it as characterize Fire qua Fire: while if it be compounded out of the elements', only the corporeal
modifications will occur in it. But the changes we have mentioned are none of them corporeal.

The discussion of these difficulties, however, is a task appropriate to a different investigation:' let us return to
the 'elements' of which bodies are composed. The theories that 'there is something common to all the
"elements'", and that they are reciprocally transformed', are so related that those who accept either are bound
to accept the other as well. Those, on the other hand, who do not make their coming-to-be reciprocal-who
refuse to suppose that any one of the 'elements' comes-to-be out of any other taken singly, except in the
sense in which bricks come-to-be out of a wall-are faced with a paradox. How, on their theory, are flesh and
bones or any of the other compounds to result from the 'elements' taken together?

Indeed, the point we have raised constitutes a problem even for those who generate the 'elements' out of one
another. In what manner does anything other than, and beside, the 'elements' come-to-be out of them? Let
me illustrate my meaning. Water can come-to-be out of Fire and Fire out of Water; for their substralum is
something common to them both. But flesh too, presumably, and marrow come-to-be out of them. How,
then, do such things come to-be? For (a) how is the manner of their coming-to-be to be conceived by those
who maintain a theory like that of Empedocles? They must conceive it as composition-just as a wall
comes-to-be out of bricks and stones: and the 'Mixture', of which they speak, will be composed of the
'elements', these being preserved in it unaltered but with their small particles juxtaposed each to each. That
will be the manner, presumably, in which flesh and every other compound results from the 'elements'.
Consequently, it follows that Fire and Water do not come-to-be 'out of any and every part of flesh'. For
instance, although a sphere might come-to-be out of this part of a lump of wax and a pyramid out of some
other part, it was nevertheless possible for either figure to have come-to-be out of either part indifferently:
that is the manner of coming-to-be when 'both Fire and Water come-to-be out of any and every part of
flesh'. Those, however, who maintain the theory in question, are not at liberty to conceive that 'both
come-to-be out of flesh' in that manner, but only as a stone and a brick 'both come-to-be out of a wall'-viz.
each out of a different place or part. Similarly (b) even for those who postulate a single matter of their
'elements' there is a certain difficulty in explaining how anything is to result from two of them taken
together-e.g. from 'cold' and hot', or from Fire and Earth. For if flesh consists of both and is neither of them,
nor again is a 'composition' of them in which they are preserved unaltered, what alternative is left except to
identify the resultant of the two 'elements' with their matter? For the passingaway of either 'element' produces

7 29

ON GENERATION AND CORRUPTION

either the other or the matter.

Perhaps we may suggest the following solution, (i) There are differences of degree in hot and cold. Although,
therefore, when either is fully real without qualification, the other will exist potentially; yet, when neither
exists in the full completeness of its being, but both by combining destroy one another's excesses so that there
exist instead a hot which (for a 'hot') is cold and a cold which (for a 'cold') is hot; then what results from these
two contraries will be neither their matter, nor either of them existing in its full reality without qualification.
There will result instead an 'intermediate': and this 'intermediate', according as it is potentially more hot than
cold or vice versa, will possess a power-of-heating that is double or triple its power-of-cooling, or
otherwise related thereto in some similar ratio. Thus all the other bodies will result from the contraries, or
rather from the 'elements', in so far as these have been 'combined': while the elements' will result from the
contraries, in so far as these 'exist potentially' in a special sense-not as matter 'exists potentially', but in the
sense explained above. And when a thing comes-to-be in this manner, the process is cobination'; whereas
what comes-to-be in the other manner is matter. Moreover (ii) contraries also 'suffer action', in accordance
with the disjunctively-articulated definition established in the early part of this work.' For the actually-hot is
potentially-cold and the actually cold potentially-hot; so that hot and cold, unless they are equally balanced,
are transformed into one another (and all the other contraries behave in a similar way). It is thus, then, that in
the first place the 'elements' are transformed; and that (in the second place) out of the 'elements' there
come-to-be flesh and bones and the like-the hot becoming cold and the cold becoming hot when they have
been brought to the 'mean'. For at the 'mean' is neither hot nor cold. The 'mean', however, is of considerable
extent and not indivisible. Similarly, it is qua reduced to a 'mean' condition that the dry and the moist, as well
as the contraries we have used as examples, produce flesh and bone and the remaining compounds.

All the compound bodies-all of which exist in the region belonging to the central body-are composed of all
the 'simple' bodies. For they all contain Earth because every 'simple' body is to be found specially and most
abundantly in its own place. And they all contain Water because (a) the compound must possess a definite
outline and Water, alone of the 'simple' bodies, is readily adaptable in shape: moreover (b) Earth has no
power of cohesion without the moist. On the contrary, the moist is what holds it together; for it would fall to
pieces if the moist were eliminated from it completely.

They contain Earth and Water, then, for the reasons we have given: and they contain Air and Fire, because
these are contrary to Earth and Water (Earth being contrary to Air and Water to Fire, in so far as one
Substance can be 'contrary' to another). Now all compounds presuppose in their coming-to-be constituents
which are contrary to one another: and in all compounds there is contained one set of the contrasted extremes.
Hence the other set must be contained in them also, so that every compound will include all the 'simple'
bodies.

Additional evidence seems to be furnished by the food each compound takes. For all of them are fed by
substances which are the same as their constituents, and all of them are fed by more substances than one.
Indeed, even the plants, though it might be thought they are fed by one substance only, viz. by Water, are fed
by more than one: for Earth has been mixed with the Water. That is why farmers too endeavour to mix before
watering. Although food is akin to the matter, that which is fed is the 'figure'-i.e. the 'form' taken along with
the matter. This fact enables us to understand why, whereas all the 'simple' bodies come-to-be out of one
another, Fire is the only one of them which (as our predecessors also assert) 'is fed'. For Fire alone-or more
than all the rest-is akin to the 'form' because it tends by nature to be borne towards the limit. Now each of
them naturally tends to be borne towards its own place; but the 'figure'-i.e. the 'form'-Of them all is at the
limits.

ON GENERATION AND CORRUPTION
Thus we have explained that all the compound bodies are composed of all the 'simple' bodies.

Since some things are such as to come-to-be and pass-away, and since coming-to-be in fact occurs in the
region about the centre, we must explain the number and the nature of the 'originative sources' of all
coming-to-be alike: for a grasp of the true theory of any universal facilitates the understanding of its specific
forms.

The 'originative sources', then, of the things which come-to-be are equal in number to, and identical in kind
with, those in the sphere of the eternal and primary things. For there is one in the sense of 'matter', and a
second in the sense of 'form': and, in addition, the third 'originative source' must be present as well. For the
two first are not sufficient to bring things into being, any more than they are adequate to account for the
primary things.

Now cause, in the sense of material origin, for the things which are such as to come-to-be is 'that which can
be-and-not-be': and this is identical with'that which can come-to-be-and-pass-away', since the latter,
while it is at one time, at another time is not. (For whereas some things are of necessity, viz. the eternal
things, others of necessity are not. And of these two sets of things, since they cannot diverge from the
necessity of their nature, it is impossible for the first not to he and impossible for the second to he. Other
things, however, can both be and not he.) Hence coming-to-be and passing-away must occur within the
field of 'that which can be-and not-be'. This, therefore, is cause in the sense of material origin for the things
which are such as to come-to-be; while cause, in the sense of their 'end', is their 'figure' or 'form'-and that is
the formula expressing the essential nature of each of them.

But the third 'originative source' must be present as well-the cause vaguely dreamed of by all our
predecessors, definitely stated by none of them. On the contrary (a) some amongst them thought the nature of
'the Forms' was adequate to account for coming-to-be. Thus Socrates in the Phaedo first blames everybody
else for having given no explanation; and then lays it down; that 'some things are Forms, others Participants
in the Forms', and that 'while a thing is said to "be" in virtue of the Form, it is said to "come-to-be" qua
sharing in," to "pass-away" qua "losing," the 'Form'. Hence he thinks that 'assuming the truth of these theses,
the Forms must be causes both of coming-to-be and of passing-away'. On the other hand (b) there were
others who thought 'the matter' was adequate by itself to account for coming-to-be, since 'the movement
originates from the matter'.

Neither of these theories, however, is sound. For (a) if the Forms are causes, why is their generating activity
intermittent instead of perpetual and continuous-since there always are Participants as well as Forms?
Besides, in some instances we see that the cause is other than the Form. For it is the doctor who implants
health and the man of science who implants science, although 'Health itself and 'Science itself are as well as
the Participants: and the same principle applies to everything else that is produced in accordance with an art.
On the other hand (b) to say that 'matter generates owing to its movement' would be, no doubt, more
scientific than to make such statements as are made by the thinkers we have been criticizing. For what 'alters'
and transfigures plays a greater part in bringing, things into being; and we are everywhere accustomed, in the
products of nature and of art alike, to look upon that which can initiate movement as the producing cause.
Nevertheless this second theory is not right either.

For, to begin with, it is characteristic of matter to suffer action, i.e. to be moved: but to move, i.e. to act,
belongs to a different 'power'. This is obvious both in the things that come-to-be by art and in those that
come to-be by nature. Water does not of itself produce out of itself an animal: and it is the art, not the wood,
that makes a bed. Nor is this their only error. They make a second mistake in omitting the more controlling

9 31

ON GENERATION AND CORRUPTION

cause: for they eliminate the essential nature, i.e. the 'form'. And what is more, since they remove the formal
cause, they invest the forces they assign to the 'simple' bodies-the forces which enable these bodies to bring
things into being-with too instrumental a character. For 'since' (as they say) 'it is the nature of the hot to
dissociate, of the cold to bring together, and of each remaining contrary either to act or to suffer action', it is
out of such materials and by their agency (so they maintain) that everything else comes-to-be and
passes-away. Yet (a) it is evident that even Fire is itself moved, i.e. suffers action. Moreover (b) their
procedure is virtually the same as if one were to treat the saw (and the various instruments of carpentry) as
'the cause' of the things that come-to-be: for the wood must be divided if a man saws, must become smooth
if he planes, and so on with the remaining tools. Hence, however true it may be that Fire is active, i.e. sets
things moving, there is a further point they fail to observe-viz. that Fire is inferior to the tools or instruments
in the manner in which it sets things moving.

As to our own theory-we have given a general account of the causes in an earlier work,' we have now
explained and distinguished the 'matter' and the 'form'. Further, since the change which is motion has been
proved' to be eternal, the continuity of the occurrence of coming-to-be follows necessarily from what we
have established: for the eternal motion, by causing 'the generator' to approach and retire, will produce
coming-to-be uninterruptedly. At the same time it is clear that we were right when, in an earlier work,' we
called motion (not coming-to-be) 'the primary form of change'. For it is far more reasonable that what is
should cause the coming-to-be of what is not, than that what is not should cause the being of what is. Now
that which is being moved is, but that which is coming-to-be is not: hence, also, motion is prior to
coming-to-be.

We have assumed, and have proved, that coming-to-be and passing-away happen to things continuously;
and we assert that motion causes coming-to-be. That being so, it is evident that, if the motion be single, both
processes cannot occur since they are contrary to one another: for it is a law of nature that the same cause,
provided it remain in the same condition, always produces the same effect, so that, from a single motion,
either coming-to-be or passing-away will always result. The movements must, on the contrary, be more
than one, and they must be contrasted with one another either by the sense of their motion or by its
irregularity: for contrary effects demand contraries as their causes.

This explains why it is not the primary motion that causes coming-to-be and passingaway, but the motion
along the inclined circle: for this motion not only possesses the necessary continuity, but includes a duality of
movements as well. For if coming-to-be and passing-away are always to be continuous, there must be some
body always being moved (in order that these changes may not fail) and moved with a duality of movements
(in order that both changes, not one only, may result). Now the continuity of this movement is caused by the
motion of the whole: but the approaching and retreating of the moving body are caused by the inclination. For
the consequence of the inclination is that the body becomes alternately remote and near; and since its distance
is thus unequal, its movement will be irregular. Therefore, if it generates by approaching and by its proximity,
it-this very same body-destroys by retreating and becoming remote: and if it generates by many successive
approaches, it also destroys by many successive retirements. For contrary effects demand contraries as their
causes; and the natural processes of passing-away and coming-to-be occupy equal periods of time. Hence,
too, the times-i.e. the lives-of the several kinds of living things have a number by which they are
distinguished: for there is an Order controlling all things, and every time (i.e. every life) is measured by a
period. Not all of them, however, are measured by the same period, but some by a smaller and others by a
greater one: for to some of them the period, which is their measure, is a year, while to some it is longer and to
others shorter.

And there are facts of observation in manifest agreement with our theories. Thus we see that coming-to-be
10 32

ON GENERATION AND CORRUPTION

occurs as the sun approaches and decay as it retreats; and we see that the two processes occupy equal times.
For the durations of the natural processes of passing-away and coming-to-be are equal. Nevertheless it
Often happens that things pass-away in too short a time. This is due to the 'intermingling' by which the things
that come-to-be and pass-away are implicated with one another. For their matter is 'irregular', i.e. is not
everywhere the same: hence the processes by which they come-to-be must be 'irregular' too, i.e. some too
quick and others too slow. Consequently the phenomenon in question occurs, because the 'irregular'
coming-to-be of these things is the passing-away of other things.

Coming-to-be and passing-away will, as we have said, always be continuous, and will never fail owing to
the cause we stated. And this continuity has a sufficient reason on our theory. For in all things, as we affirm,
Nature always strives after 'the better'. Now 'being' (we have explained elsewhere the exact variety of
meanings we recognize in this term) is better than 'not-being': but not all things can possess 'being', since
they are too far removed from the 'originative source. 'God therefore adopted the remaining alternative, and
fulfilled the perfection of the universe by making coming-to-be uninterrupted: for the greatest possible
coherence would thus be secured to existence, because that 'coming-to-be should itself come-to-be
perpetually' is the closest approximation to eternal being.

The cause of this perpetuity of coming-to-be, as we have often said, is circular motion: for that is the only
motion which is continuous. That, too, is why all the other things-the things, I mean, which are reciprocally
transformed in virtue of their 'passions' and their 'powers of action' e.g. the 'simple' bodiesimitate circular
motion. For when Water is transformed into Air, Air into Fire, and the Fire back into Water, we say the
coming-to-be 'has completed the circle', because it reverts again to the beginning. Hence it is by imitating
circular motion that rectilinear motion too is continuous.

These considerations serve at the same time to explain what is to some people a baffling problem-viz. why
the 'simple' bodies, since each them is travelling towards its own place, have not become dissevered from one
another in the infinite lapse of time. The reason is their reciprocal transformation. For, had each of them
persisted in its own place instead of being transformed by its neighbour, they would have got dissevered long
ago. They are transformed, however, owing to the motion with its dual character: and because they are
transformed, none of them is able to persist in any place allotted to it by the Order.

It is clear from what has been said (i) that coming-to-be and passing-away actually occur, (ii) what causes
them, and (iii) what subject undergoes them. But (a) if there is to be movement (as we have explained
elsewhere, in an earlier work') there must be something which initiates it; if there is to be movement always,
there must always be something which initiates it; if the movement is to be continuous, what initiates it must
be single, unmoved, ungenerated, and incapable of 'alteration'; and if the circular movements are more than
one, their initiating causes must all of them, in spite of their plurality, be in some way subordinated to a
single 'originative source'. Further (b) since time is continuous, movement must be continuous, inasmuch as
there can be no time without movement. Time, therefore, is a 'number' of some continuous movement-a
'number', therefore, of the circular movement, as was established in the discussions at the beginning. But (c)
is movement continuous because of the continuity of that which is moved, or because that in which the
movement occurs (I mean, e.g. the place or the quality) is continuous? The answer must clearly be 'because
that which is moved is continuous'. (For how can the quality be continuous except in virtue of the continuity
of the thing to which it belongs? But if the continuity of 'that in which' contributes to make the movement
continuous, this is true only of 'the place in which'; for that has 'magnitude' in a sense.) But (d) amongst
continuous bodies which are moved, only that which is moved in a circle is 'continuous' in such a way that it
preserves its continuity with itself throughout the movement. The conclusion therefore is that this is what
produces continuous movement, viz. the body which is being moved in a circle; and its movement makes
time continuous.

10 33

ON GENERATION AND CORRUPTION

Wherever there is continuity in any process (coming-to-be or 'alteration' or any kind of change whatever) we
observe consecutiveness', i.e. this coming-to-be after that without any interval. Hence we must investigate
whether, amongst the consecutive members, there is any whose future being is necessary; or whether, on the
contrary, every one of them may fail to come-to-be. For that some of them may fail to occur, is clear, (a) We
need only appeal to the distinction between the statements 'x will be' and 'x is about to which depends upon
this fact. For if it be true to say of x that it 'will be', it must at some time be true to say of it that 'it is':
whereas, though it be true to say of x now that 'it is about to occur', it is quite possible for it not to
come-to-be-thus a man might not walk, though he is now 'about to' walk. And (b) since (to appeal to a
general principle) amongst the things which 'are' some are capable also of 'not-being', it is clear that the same
ambiguous character will attach to them no less when they are coming-to-be: in other words, their
coming-to-be will not be necessary.

Then are all the things that come-to-be of this contingent character? Or, on the contrary, is it absolutely
necessary for some of them to come-to-be? Is there, in fact, a distinction in the field of 'coming-to-be'
corresponding to the distinction, within the field of 'being', between things that cannot possibly 'not-be' and
things that can 'not-be'? For instance, is it necessary that solstices shall come-to-be, i.e. impossible that they
should fail to be able to occur?

Assuming that the antecedent must have come-to-be if the consequent is to be (e.g. that foundations must
have come-to-be if there is to be a house: clay, if there are to be foundations), is the converse also true? If
foundations have come-to-be, must a house come-to-be? The answer seems to be that the necessary nexus
no longer holds, unless it is 'necessary' for the consequent (as well as for the antecedent) to
come-to-be-'necessary' absolutely. If that be the case, however, 'a house must come to-be if foundations
have come-to-be', as well as vice versa. For the antecedent was assumed to be so related to the consequent
that, if the latter is to be, the antecedent must have come-tobe before it. If, therefore, it is necessary that the
consequent should come-to-be, the antecedent also must have come-to-be: and if the antecedent has
come-to-be, then the consequent also must come-to-be-not, however, because of the antecedent, but
because the future being of the consequent was assumed as necessary. Hence, in any sequence, when the
being of the consequent is necessary, the nexus is reciprocal-in other words, when the antecedent has
come-to-be the consequent must always come-to-be too.

Now (i) if the sequence of occurrences is to proceed ad infinitum 'downwards', the coming to-be of any
determinate 'this' amongst the later members of the sequence will not be absolutely, but only conditionally,
necessary. For it will always be necessary that some other member shall have come-to-be before 'this' as the
presupposed condition of the necessity that 'this' should come-to-be: consequently, since what is 'infinite'
has no 'originative source', neither will there be in the infinite sequence any 'primary' member which will
make it 'necessary' for the remaining members to come-to-be.

Nor again (ii) will it be possible to say with truth, even in regard to the members of a limited sequence, that it
is 'absolutely necessary' for any one of them to come-to-be. We cannot truly say, e.g. that 'it is absolutely
necessary for a house to come-to-be when foundations have been laid': for (unless it is always necessary for
a house to be coming-to-be) we should be faced with the consequence that, when foundations have been
laid, a thing, which need not always be, must always be. No: if its coming-to-be is to be 'necessary', it must
be 'always' in its coming-to-be. For what is 'of necessity' coincides with what is 'always', since that which
'must be' cannot possibly 'not-be'. Hence a thing is eternal if its 'being' is necessary: and if it is eternal, its
'being' is necessary. And if, therefore, the 'coming-to-be' of a thing is necessary, its 'coming-to-be' is
eternal; and if eternal, necessary.

11 34

ON GENERATION AND CORRUPTION

It follows that the coming-to-be of anything, if it is absolutely necessary, must be cyclical-i.e. must return
upon itself. For coming to-be must either be limited or not limited: and if not limited, it must be either
rectilinear or cyclical. But the first of these last two alternatives is impossible if coming-to-be is to be
eternal, because there could not be any 'originative source' whatever in an infinite rectilinear sequence,
whether its members be taken 'downwards' (as future events) or 'upwards' (as past events). Yet coming-to-be
must have an 'originative source' (if it is to be necessary and therefore eternal), nor can it be eternal if it is
limited. Consequently it must be cyclical. Hence the nexus must be reciprocal. By this I mean that the
necessary occurrence of 'this' involves the necessary occurrence of its antecedent: and conversely that, given
the antecedent, it is also necessary for the consequent to come-to-be. And this reciprocal nexus will hold
continuously throughout the sequence: for it makes no difference whether the reciprocal nexus, of which we
are speaking, is mediated by two, or by many, members.

It is in circular movement, therefore, and in cyclical coming-to-be that the 'absolutely necessary' is to be
found. In other words, if the coming-to-be of any things is cyclical, it is 'necessary' that each of them is
coming-to-be and has come-to-be: and if the coming-to-be of any things is 'necessary', their
coming-to-be is cyclical.

The result we have reached is logically concordant with the eternity of circular motion, i.e. the eternity of the
revolution of the heavens (a fact which approved itself on other and independent evidence),' since precisely
those movements which belong to, and depend upon, this eternal revolution 'come-to-be' of necessity, and of
necessity 'will be'. For since the revolving body is always setting something else in motion, the movement of
the things it moves must also be circular. Thus, from the being of the 'upper revolution' it follows that the sun
revolves in this determinate manner; and since the sun revolves thus, the seasons in consequence come-to-be
in a cycle, i.e. return upon themselves; and since they come-to-be cyclically, so in their turn do the things
whose coming-to-be the seasons initiate.

Then why do some things manifestly come to-be in this cyclical fashion (as, e.g. showers and air, so that it
must rain if there is to be a cloud and, conversely, there must be a cloud if it is to rain), while men and
animals do not 'return upon themselves' so that the same individual comes-to-be a second time (for though
your coming-to-be presupposes your father's, his coming-to-be does not presuppose yours)? Why, on the
contrary, does this coming-to-be seem to constitute a rectilinear sequence?

In discussing this new problem, we must begin by inquiring whether all things 'return upon themselves' in a
uniform manner; or whether, on the contrary, though in some sequences what recurs is numerically the same,
in other sequences it is the same only in species. In consequence of this distinction, it is evident that those
things, whose 'substance'-that which is undergoing the process-is imperishable, will be numerically, as well
as specifically, the same in their recurrence: for the character of the process is determined by the character of
that which undergoes it. Those things, on the other hand, whose 'substance' is perish, able (not imperishable)
must 'return upon themselves' in the sense that what recurs, though specifically the same, is not the same
numerically. That why, when Water comes-to-be from Air and Air from Water, the Air is the same
'specifically', not 'numerically': and if these too recur numerically the same, at any rate this does not happen
with things whose 'substance' comes-to-be-whose 'substance' is such that it is essentially capable of
not-being.

-THE END-

11 35

ON THE GENERATION OF ANIMALS

by Aristotle

ON THE GENERATION OF ANIMALS

Table of Contents

ON THE GENERATION OF ANIMALS . 1

by Aristotle 1

Book 1 2

_1 2

2 3

_3 4

A 4

_5 5

_6 5

7 6

JO 6

11 7

12 7

13 8

14 8

15 8

16 9

17 9

18 10

19 15

.20 17

H 18

22 19

23 20

Book II . 21

1 21

2 25

1 26

A 28

1 31

6 32

2 37

_8 38

Book III 40

1 40

2 43

1 45

A 46

1 46

6 48

1_ 48

_8 49

_9 49

10 50

11 52

Book IV 55

ON THE GENERATION OF ANIMALS

Table of Contents

J. 55

2 59

_3 59

A 62

_5 66

6 67

1 69

_9 70

JO 71

Book V. 71

_1 71

2 75

3. 76

A 78

5. 79

6 79

1 80

8 82

ON THE GENERATION OF ANIMALS

by Aristotle

translated by Arthur Piatt

• Book I

• 1

• 2

• 3
•4
•5
•6
•7
•8
•9

• 10
•11
•12
•13

• 14
•11

• 16

•12

• 18

• 19

• 20

•21

• 22

•23

• Book II

• 1

• 2
•3
•4
•5
•6
•7
•8

• Book III

• 1
•2
•3
•4
•5

ON THE GENERATION OF ANIMALS

•6
•7
•8
•9

• 10

•11

• Book IV

• 1
•2
•3
•4
•5
•6
•7
•8
•9

• 10

• Book V

• 1

• 2

• 3
•4
•5
•6
•7

Book I

WE have now discussed the other parts of animals, both generally and with reference to the peculiarities of
each kind, explaining how each part exists on account of such a cause, and I mean by this the final cause.

There are four causes underlying everything: first, the final cause, that for the sake of which a thing exists;
secondly, the formal cause, the definition of its essence (and these two we may regard pretty much as one and
the same); thirdly, the material; and fourthly, the moving principle or efficient cause.

We have then already discussed the other three causes, for the definition and the final cause are the same, and
the material of animals is their parts of the whole animal the non-homogeneous parts, of these again the
homogeneous, and of these last the so-called elements of all matter. It remains to speak of those parts which
contribute to the generation of animals and of which nothing definite has yet been said, and to explain what is
the moving or efficient cause. To inquire into this last and to inquire into the generation of each animal is in a
way the same thing; and, therefore, my plan has united them together, arranging the discussion of these parts
last, and the beginning of the question of generation next to them.

Now some animals come into being from the union of male and female, i.e. all those kinds of animal which
possess the two sexes. This is not the case with all of them; though in the sanguinea with few exceptions the

Book I 2

ON THE GENERATION OF ANIMALS

creature, when its growth is complete, is either male or female, and though some bloodless animals have
sexes so that they generate offspring of the same kind, yet other bloodless animals generate indeed, but not
offspring of the same kind; such are all that come into being not from a union of the sexes, but from decaying
earth and excrements. To speak generally, if we take all animals which change their locality, some by
swimming, others by flying, others by walking, we find in these the two sexes, not only in the sanguinea but
also in some of the bloodless animals; and this applies in the case of the latter sometimes to the whole class,
as the cephalopoda and Crustacea, but in the class of insects only to the majority. Of these, all which are
produced by union of animals of the same kind generate also after their kind, but all which are not produced
by animals, but from decaying matter, generate indeed, but produce another kind, and the offspring is neither
male nor female; such are some of the insects. This is what might have been expected, for if those animals
which are not produced by parents had themselves united and produced others, then their offspring must have
been either like or unlike to themselves. If like, then their parents ought to have come into being in the same
way; this is only a reasonable postulate to make, for it is plainly the case with other animals. If unlike, and yet
able to copulate, then there would have come into being again from them another kind of creature and again
another from these, and this would have gone on to infinity. But Nature flies from the infinite, for the infinite
is unending or imperfect, and Nature ever seeks an end.

But all those creatures which do not move, as the testacea and animals that live by clinging to something else,
inasmuch as their nature resembles that of plants, have no sex any more than plants have, but as applied to
them the word is only used in virtue of a similarity and analogy. For there is a slight distinction of this sort,
since even in plants we find in the same kind some trees which bear fruit and others which, while bearing
none themselves, yet contribute to the ripening of the fruits of those which do, as in the case of the fig-tree
and caprifig.

The same holds good also in plants, some coming into being from seed and others, as it were, by the
spontaneous action of Nature, arising either from decomposition of the earth or of some parts in other plants,
for some are not formed by themselves separately but are produced upon other trees, as the mistletoe. Plants,
however, must be investigated separately.

Of the generation of animals we must speak as various questions arise in order in the case of each, and we
must connect our account with what has been said. For, as we said above, the male and female principles may
be put down first and foremost as origins of generation, the former as containing the efficient cause of
generation, the latter the material of it. The most conclusive proof of this is drawn from considering how and
whence comes the semen; for there is no doubt that it is out of this that those creatures are formed which are
produced in the ordinary course of Nature; but we must observe carefully the way in which this semen
actually comes into being from the male and female. For it is just because the semen is secreted from the two
sexes, the secretion taking place in them and from them, that they are first principles of generation. For by a
male animal we mean that which generates in another, and by a female that which generates in itself;
wherefore men apply these terms to the macrocosm also, naming Earth mother as being female, but
addressing Heaven and the Sun and other like entities as fathers, as causing generation.

Male and female differ in their essence by each having a separate ability or faculty, and anatomically by
certain parts; essentially the male is that which is able to generate in another, as said above; the female is that
which is able to generate in itself and out of which comes into being the offspring previously existing in the
parent. And since they are differentiated by an ability or faculty and by their function, and since instruments
or organs are needed for all functioning, and since the bodily parts are the instruments or organs to serve the
faculties, it follows that certain parts must exist for union of parents and production of offspring. And these
must differ from each other, so that consequently the male will differ from the female. (For even though we

ON THE GENERATION OF ANIMALS

speak of the animal as a whole as male or female, yet really it is not male or female in virtue of the whole of
itself, but only in virtue of a certain faculty and a certain part- just as with the part used for sight or
locomotion- which part is also plain to sense-perception.)

Now as a matter of fact such parts are in the female the so-called uterus, in the male the testes and the penis,
in all the sanguinea; for some of them have testes and others the corresponding passages. There are
corresponding differences of male and female in all the bloodless animals also which have this division into
opposite sexes. But if in the sanguinea it is the parts concerned in copulation that differ primarily in their
forms, we must observe that a small change in a first principle is often attended by changes in other things
depending on it. This is plain in the case of castrated animals, for, though only the generative part is disabled,
yet pretty well the whole form of the animal changes in consequence so much that it seems to be female or
not far short of it, and thus it is clear than an animal is not male or female in virtue of an isolated part or an
isolated faculty. Clearly, then, the distinction of sex is a first principle; at any rate, when that which
distinguishes male and female suffers change, many other changes accompany it, as would be the case if a
first principle is changed.

The sanguinea are not all alike as regards testes and uterus. Taking the former first, we find that some of them
have not testes at all, as the classes of fish and of serpents, but only two spermatic ducts. Others have testes
indeed, but internally by the loin in the region of the kidneys, and from each of these a duct, as in the case of
those animals which have no testes at all, these ducts unite also as with those animals; this applies (among
animals breathing air and having a lung) to all birds and oviparous quadrupeds. For all these have their testes
internal near the loin, and two ducts from these in the same way as serpents; I mean the lizards and tortoises
and all the scaly reptiles. But all the vivipara have their testes in front; some of them inside at the end of the
abdomen, as the dolphin, not with ducts but with a penis projecting externally from them; others outside,
either pendent as in man or towards the fundament as in swine. They have been discriminated more
accurately in the Enquiries about Animals.

The uterus is always double, just as the testes are always two in the male. It is situated either near the
pudendum (as in women, and all those animals which bring forth alive not only externally but also internally,
and all fish that lay eggs externally) or up towards the hypozoma (as in all birds and in viviparous fishes).
The uterus is also double in the Crustacea and the cephalopoda, for the membranes which include their
so-called eggs are of the nature of a uterus. It is particularly hard to distinguish in the case of the poulps, so
that it seems to be single, but the reason of this is that the bulk of the body is everywhere similar.

It is double also in the larger insects; in the smaller the question is uncertain owing to the small size of the
body.

Such is the description of the aforesaid parts of animals.

With regard to the difference of the spermatic organs in males, if we are to investigate the causes of their
existence, we must first grasp the final cause of the testes. Now if Nature makes everything either because it
is necessary or because it is better so, this part also must be for one of these two reasons. But that it is not
necessary for generation is plain; else had it been possessed by all creatures that generate, but as it is neither
serpents have testes nor have fish; for they have been seen uniting and with their ducts full of milt. It remains
then that it must be because it is somehow better so. Now it is true that the business of most animals is, you
may say, nothing else than to produce young, as the business of a plant is to produce seed and fruit. But still

ON THE GENERATION OF ANIMALS

as, in the case of nutriment, animals with straight intestines are more violent in their desire for food, so those
which have not testes but only ducts, or which have them indeed but internally, are all quicker in
accomplishing copulation. But those which are to be more temperate in the one case have not straight
intestines, and in the other have their ducts twisted to prevent their desire being too violent and hasty. It is for
this that the testes are contrived; for they make the movement of the spermatic secretion steadier, preserving
the folding back of the passages in the vivipara, as horses and the like, and in man. (For details see the
Enquiries about Animals.) For the testes are no part of the ducts but are only attached to them, as women
fasten stones to the loom when weaving; if they are removed the ducts are drawn up internally, so that
castrated animals are unable to generate; if they were not drawn up they would be able, and before now a bull
mounting immediately after castration has caused conception in the cow because the ducts had not yet been
drawn up. In birds and oviparous quadrupeds the testes receive the spermatic secretion, so that its expulsion is
slower than in fishes. This is clear in the case of birds, for their testes are much enlarged at the time of
copulation, and all those which pair at one season of the year have them so small when this is past that they
are almost indiscernible, but during the season they are very large. When the testes are internal the act of
copulation is quicker than when they are external, for even in the latter case the semen is not emitted before
the testes are drawn up.

Besides, quadrupeds have the organ of copulation, since it is possible for them to have it, but for birds and the
footless animals it is not possible, because the former have their legs under the middle of the abdomen and
the latter have no legs at all; now the penis depends from that region and is situated there. (Wherefore also the
legs are strained in intercourse, both the penis and the legs being sinewy.) So that, since it is not possible for
them to have this organ, they must necessarily either have no testes also, or at any rate not have them there, as
those animals that have both penis and testes have them in the same situation.

Further, with those animals at any rate that have external testes, the semen is collected together before
emission, and emission is due to the penis being heated by its movement; it is not ready for emission at
immediate contact as in fishes.

All the vivipira have their testes in front, internally or externally, except the hedgehog; he alone has them
near the loin. This is for the same reason as with birds, because their union must be quick, for the hedgehog
does not, like the other quadrupeds, mount upon the back of the female, but they conjugate standing upright
because of their spines.

So much for the reasons why those animals have testes which have them, and why they are sometimes
external and sometimes internal.

All those animals which have no testes are deficient in this part, as has been said, not because it is better to be
so but simply because of necessity, and secondly because it is necessary that their copulation should be
speedy. Such is the nature of fish and serpents. Fish copulate throwing themselves alongside of the females
and separating again quickly. For as men and all such creatures must hold their breath before emitting the
semen, so fish at such times must cease taking in the sea-water, and then they perish easily. Therefore they
must not mature the semen during copulation, as viviparous land-animals do, but they have it all matured
together before the time, so as not to be maturing it while in contact but to emit it ready matured. So they
have no testes, and the ducts are straight and simple. There is a small part similar to this connected with the
testes in the system of quadrupeds, for part of the reflected duct is sanguineous and part is not; the fluid is
already semen when it is received by and passes through this latter part, so that once it has arrived there it is

ON THE GENERATION OF ANIMALS

soon emitted in these quadrupeds also. Now in fishes the whole passage resembles the last section of the
reflected part of the duct in man and similar animals.

Serpents copulate twining round one another, and, as said above, have neither testes nor penis, the latter
because they have no legs, the former because of their length, but they have ducts like for on account of their
extreme length the seminal fluid would take too long in its passage and be cooled if it were further delayed by
testes. (This happens also if the penis is large; such men are less fertile than when it is smaller because the
semen, if cold, is not generative, and that which is carried too far is cooled.) So much for the reason why
some animals have testes and others not. Serpents intertwine because of their inaptitude to cast themselves
alongside of one another. For they are too long to unite closely with so small a part and have no organs of
attachment, so they make use of the suppleness of their bodies, intertwining. Wherefore also they seem to be
slower in copulation than fish, not only on account of the length of the ducts but also of this elaborate
arrangement in uniting.

It is not easy to state the facts about the uterus in female animals, for there are many points of difference. The
vivipara are not alike in this part; women and all the vivipara with feet have the uterus low down by the
pudendum, but the cartilaginous viviparous fish have it higher up near the hypozoma. In the ovipara, again, it
is low in fish (as in women and the viviparous quadrupeds), high in birds and all oviparous quadrupeds. Yet
even these differences are on a principle. To begin with the ovipara, they differ in the manner of laying their
eggs, for some produce them imperfect, as fishes whose eggs increase and are finally developed outside of
them. The reason is that they produce many young, and this is their function as it is with plants. If then they
perfected the egg in themselves they must needs be few in number, but as it is, they have so many that each
uterus seems to be an egg, at any rate in the small fishes. For these are the most productive, just as with the
other animals and plants whose nature is analogous to theirs, for the increase of size turns with them to seed.

But the eggs of birds and the quadrupedal ovipara are perfect when produced. In order that these may be
preserved they must have a hard covering (for their envelope is soft so long as they are increasing in size),
and the shell is made by heat squeezing out the moisture for the earthy material; consequently the place must
be hot in which this is to happen. But the part about the hypozoma is hot, as is shown by that being the part
which concocts the food. If then the eggs must be within the uterus, then the uterus must be near the
hypozoma in those creatures which produce their eggs in a perfect form. Similarly it must be low down in
those which produce them imperfect, for it is profitable that it should be so. And it is more natural for the
uterus to be low down than high up, when Nature has no other business in hand to hinder it; for its end is low
down, and where is the end, there is the function, and the uterus itself is naturally where the function is.

We find differences in the vivipara also as compared with one another. Some produce their young alive, not
only externally, but also internally, as men, horses, dogs, and all those which have hair, and among aquatic
animals, dolphins, whales, and such cetacea.

But the cartilaginous fish and the vipers produce their young alive externally, but first produce eggs
internally. The egg is perfect, for so only can an animal be generated from an egg, and nothing comes from an
imperfect one. It is because they are of a cold nature, not hot as some assert, that they do not lay their eggs

ON THE GENERATION OF ANIMALS

externally.

At least they certainly produce their eggs in a soft envelope, the reason being that they have but little heat and
so their nature does not complete the process of drying the egg-shell. Because, then, they are cold they
produce soft-shelled eggs, and because the eggs are soft they do not produce them externally; for that would
have caused their destruction.

The process is for the most part the same as in birds, for the egg descends and the young is hatched from it
near the vagina, where the young is produced in those animals which are viviparous from the beginning.
Therefore in such animals the uterus is dissimilar to that of both the vivipara and ovipara, because they
participate in both classes; for it is at once near the hypozoma and also stretching along downwards in all the
cartilaginous fishes. But the facts about this and the other kinds of uterus must be gathered from inspection of
the drawings of dissections and from the Enquiries. Thus, because they are oviparous, laying perfect eggs,
they have the uterus placed high, but, as being viviparous, low, participating in both classes.

Animals that are viviparous from the beginning all have it low, Nature here having no other business to
interfere with her, and their production having no double character. Besides this, it is impossible for animals
to be produced alive near the hypozoma, for the foetus must needs be heavy and move, and that region in the
mother is vital and would not be able to bear the weight and the movement. Thirdly, parturition would be
difficult because of the length of the passage to be traversed; even as it is there is difficulty with women if
they draw up the uterus in parturition by yawning or anything of the kind, and even when empty it causes a
feeling of suffocation if moved upwards. For if a uterus is to hold a living animal it must be stronger than in
ovipara, and therefore in all the vivipara it is fleshy, whereas when the uterus is near the hypozoma it is
membranous. And this is clear also in the case of the animals which produce young by the mixed method, for
their eggs are high up and sideways, but the living young are produced in the lower part of the uterus.

So much for the reason why differences are found in the uterus of various animals, and generally why it is
low in some and high in others near the hypozoma.

Why is the uterus always internal, but the testes sometimes internal, sometimes external? The reason for the
uterus always being internal is that in this is contained the egg or foetus, which needs guarding, shelter, and
maturation by concoction, while the outer surface of the body is easily injured and cold. The testes vary in
position because they also need shelter and a covering to preserve them and to mature the semen; for it would
be impossible for them, if chilled and stiffened, to be drawn up and discharge it. Therefore, whenever the
testes are visible, they have a cuticular covering known as the scrotum. If the nature of the skin is opposed to
this, being too hard to be adapted for enclosing them or for being soft like a true 'skin', as with the scaly
integument of fish and reptiles, then the testes must needs be internal. Therefore they are so in dolphins and
all the cetacea which have them, and in the oviparous quadrupeds among the scaly animals. The skin of birds
also is hard so that it will not conform to the size of anything and enclose it neatly. (This is another reason
with all these animals for their testes being internal besides those previously mentioned as arising necessarily
from the details of copulation.) For the same reason they are internal in the elephant and hedgehog, for the
skin of these, too, is not well suited to keep the protective part separate.

[The position of the uterus differs in animals viviparous within themselves and those externally oviparous,
and in the latter class again it differs in those which have the uterus low and those which have it near the
hypozoma, as in fishes compared with birds and oviparous quadrupeds. And it is different again in those

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ON THE GENERATION OF ANIMALS

which produce young in both ways, being oviparous internally and viviparous externally. For those which are
viviparous both internally and externally have the uterus placed on the abdomen, as men, cattle, dogs, and the
like, since it is expedient for the safety and growth of the foetus that no weight should be upon the uterus.]

The passages also are different through which the solid and liquid excreta pass out in all the vivipara.
Wherefore both males and females in this class all have a part whereby the urine is voided, and this serves
also for the issue of the semen in males, of the offspring in females. This passage is situated above and in
front of the passage of the solid excreta. The passage is the same as that of the solid nutriment in all those
animals that have no penis, in all the ovipara, even those of them that have a bladder, as the tortoises. For it is
for the sake of generation, not for the evacuation of the urine, that the passages are double; but because the
semen is naturally liquid, the liquid excretion also shares the same passage. This is clear from the fact that all
animals produce semen, but all do not void liquid excrement. Now the spermatic passages of the male must
be fixed and must not wander, and the same applies to the uterus of the female, and this fixing must take
place at either the front or the back of the body. To take the uterus first, it is in the front of the body in
vivipara because of the foetus, but at the loin and the back in ovipara. All animals which are internally
oviparous and externally viviparous are in an intermediate condition because they participate in both classes,
being at once oviparous and viviparous. For the upper part of the uterus, where the eggs are produced, is
under the hypozoma by the loin and the back, but as it advances is low at the abdomen; for it is in that part
that the animal is viviparous. In these also the passage for solid excrement and for copulation is the same, for
none of these, as has been said already, has a separate pudendum.

The same applies to the passages in the male, whether they have testes or no, as to the uterus of the ovipara.
For in all of them, not only in the ovipara, the ducts adhere to the back and the region of the spine. For they
must not wander but be settled, and that is the character of the region of the back, which gives continuity and
stability. Now in those which have internal testes, the ducts are fixed from the first, and they are fixed in like
manner if the testes are external; then they meet together towards the region of the penis.

The like applies to the ducts in the dolphins, but they have their testes hidden under the abdominal cavity.

We have now discussed the situation of the parts contributing to generation, and the causes thereof.

The bloodless animals do not agree either with the sanguinea or with each other in the fashion of the parts
contributing to generation. There are four classes still left to deal with, first the Crustacea, secondly the
cephalopoda, thirdly the insects, and fourthly the testacea. We cannot be certain about all of them, but that
most of them copulate is plain; in what manner they unite must be stated later.

The Crustacea copulate like the retromingent quadrupeds, fitting their tails to one another, the one supine and
the other prone. For the flaps attached to the sides of the tail being long prevent them from uniting with the
belly against the back. The males have fine spermatic ducts, the females a membranous uterus alongside the
intestine, cloven on each side, in which the egg is produced.

The cephalopoda entwine together at the mouth, pushing against one another and enfolding their arms. This
attitude is necessary, because Nature has bent backwards the end of the intestine and brought it round near the
mouth, as has been said before in the treatise on the parts of animals. The female has a part corresponding to

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ON THE GENERATION OF ANIMALS

the uterus, plainly to be seen in each of these animals, for it contains an egg which is at first indivisible to the
eye but afterwards splits up into many; each of these eggs is imperfect when deposited, as with the oviparous
fishes. In the cephalopoda (as also in the Crustacea) the same passage serves to void the excrement and leads
to the part like a uterus, for the male discharges the seminal fluid through this passage. And it is on the lower
surface of the body, where the mantle is open and the sea-water enters the cavity. Hence the union of the
male with the female takes place at this point, for it is necessary, if the male discharges either semen or a part
of himself or any other force, that he should unite with her at the uterine passage. But the insertion, in the
case of the poulps, of the arm of the male into the funnel of the female, by which arm the fishermen say the
male copulates with her, is only for the sake of attachment, and it is not an organ useful for generation, for it
is outside the passage in the male and indeed outside the body of the male altogether.

Sometimes also cephalopoda unite by the male mounting on the back of the female, but whether for
generation or some other cause has not yet been observed.

Some insects copulate and the offspring are produced from animals of the same name, just as with the
sanguinea; such are the locusts, cicadae, spiders, wasps, and ants. Others unite indeed and generate; but the
result is not a creature of the same kind, but only a scolex, and these insects do not come into being from
animals but from putrefying matter, liquid or solid; such are fleas, flies, and cantharides. Others again are
neither produced from animals nor unite with each other; such are gnats, 'conopes', and many similar kinds.
In most of those which unite the female is larger than the male. The males do not appear to have spermatic
passages. In most cases the male does not insert any part into the female, but the female from below upwards
into the male; this has been observed in many cases (as also that the male mounts the female), the opposite in
few cases; but observations are not yet comprehensive enough to enable us to make a distinction of classes.
And generally it is the rule with most of the oviparous fish and oviparous quadrupeds that the female is larger
than the because this is expedient in view of the increase of bulk in conception by reason of the eggs. In the
female the part analogous to the uterus is cleft and extends along the intestine, as with the other animals; in
this are produced the results of conception. This is clear in locusts and all other large insects whose nature it
is to unite; most insects are too small to be observed in this respect.

Such is the character of the generative organs in animals which were not spoken of before. It remains now to
speak of the homogeneous parts concerned, the seminal fluid and milk. We will take the former first, and
treat of milk afterwards.

Some animals manifestly emit semen, as all the sanguinea, but whether the insects and cephalopoda do so is
uncertain. Therefore this is a question to be considered, whether all males do so, or not all; and if not all, why
some do and some not; and whether the female also contributes any semen or not; and, if not semen, whether
she does not contribute anything else either, or whether she contributes something else which is not semen.
We must also inquire what those animals which emit semen contribute by means of it to generation, and
generally what is the nature of semen, and of the so-called catamenia in all animals which discharge this
liquid.

Now it is thought that all animals are generated out of semen, and that the semen comes from the parents.
Wherefore it is part of the same inquiry to ask whether both male and female produce it or only one of them,
and to ask whether it comes from the whole of the body or not from the whole; for if the latter is true it is
reasonable to suppose that it does not come from both parents either. Accordingly, since some say that it
comes from the whole of the body, we must investigate this question first.

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ON THE GENERATION OF ANIMALS

The proofs from which it can be argued that the semen comes from each and every part of the body may be
reduced to four. First, the intensity of the pleasure of coition; for the same state of feeling is more pleasant if
multiplied, and that which affects all the parts is multiplied as compared with that which affects only one or a
few. Secondly, the alleged fact that mutilations are inherited, for they argue that since the parent is deficient
in this part the semen does not come from thence, and the result is that the corresponding part is not formed
in the offspring. Thirdly, the resemblances to the parents, for the young are born like them part for part as
well as in the whole body; if then the coming of the semen from the whole body is cause of the resemblance
of the whole, so the parts would be like because it comes from each of the parts. Fourthly, it would seem to
be reasonable to say that as there is some first thing from which the whole arises, so it is also with each of the
parts, and therefore if semen or seed is cause of the whole so each of the parts would have a seed peculiar to
itself. And these opinions are plausibly supported by such evidence as that children are born with a likeness
to their parents, not in congenital but also in acquired characteristics; for before now, when the parents have
had scars, the children have been born with a mark in the form of the scar in the same place, and there was a
case at Chalcedon where the father had a brand on his arm and the letter was marked on the child, only
confused and not clearly articulated. That is pretty much the evidence on which some believe that the semen
comes from all the body.

On examining the question, however, the opposite appears more likely, for it is not hard to refute the above
arguments and the view involves impossibilities. First, then, the resemblance of children to parents is no
proof that the semen comes from the whole body, because the resemblance is found also in voice, nails, hair,
and way of moving, from which nothing comes. And men generate before they yet have certain characters,
such as a beard or grey hair. Further, children are like their more remote ancestors from whom nothing has
come, for the resemblances recur at an interval of many generations, as in the case of the woman in Elis who
had intercourse with the Aethiop; her daughter was not an Aethiop but the son of that daughter was. The
same thing applies also to plants, for it is clear that if this theory were true the seed would come from all parts
of plants also; but often a plant does not possess one part, and another part may be removed, and a third
grows afterwards. Besides, the seed does not come from the pericarp, and yet this also comes into being with
the same form as in the parent plant.

We may also ask whether the semen comes from each of the homogeneous parts only, such as flesh and bone
and sinew, or also from the heterogeneous, such as face and hands. For if from the former only, we object
that resemblance exists rather in the heterogeneous parts, such as face and hands and feet; if then it is not
because of the semen coming from all parts that children resemble their parents in these, what is there to stop
the homogeneous parts also from being like for some other reason than this? If the semen comes from the
heterogeneous alone, then it does not come from all parts; but it is more fitting that it should come from the
homogeneous parts, for they are prior to the heterogeneous which are composed of them; and as children are
born like their parents in face and hands, so they are, necessarily, in flesh and nails. If the semen comes from
both, what would be the manner of generation? For the heteroeneous parts are composed of the homogneous,
so that to come from the former would be to come from the latter and from their composition. To make this
clearer by an illustration, take a written name; if anything came from the whole of it, it would be from each of
the syllables, and if from these, from the letters and their composition. So that if really flesh and bones are
composed of fire and the like elements, the semen would come rather from the elements than anything else,
for how can it come from their composition? Yet without this composition there would be no resemblance. If
again something creates this composition later, it would be this that would be the cause of the resemblance,
not the coming of the semen from every part of the body.

Further, if the parts of the future animal are separated in the semen, how do they live? and if they are
connected, they would form a small animal.

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ON THE GENERATION OF ANIMALS

And what about the generative parts? For that which comes from the male is not similar to what comes from
the female.

Again, if the semen comes from all parts of both parents alike, the result is two animals, for the offspring will
have all the parts of both. Wherefore Empedocles seems to say what agrees pretty well with this view (if we
are to adopt it), to a certain extent at any rate, but to be wrong if we think otherwise. What he says agrees
with it when he declares that there is a sort of tally in the male and female, and that the whole offspring does
not come from either, 'but sundered is the fashion of limbs, some in man's...' For why does not the female
generate from herself if the semen comes from all parts alike and she has a receptacle ready in the uterus?
But, it seems, either it does not come from all the parts, or if it does it is in the way Empedocles says, not the
same parts coming from each parent, which is why they need intercourse with each other.

Yet this also is impossible, just as much as it is impossible for the parts when full grown to survive and have
life in them when torn apart, as Empedocles accounts for the creation of animals; in the time of his 'Reign of
Love', says he, 'many heads sprang up without necks,' and later on these isolated parts combined into animals.
Now that this is impossible is plain, for neither would the separate parts be able to survive without having any
soul or life in them, nor if they were living things, so to say, could several of them combine so as to become
one animal again. Yet those who say that semen comes from the whole of the body really have to talk in that
way, and as it happened then in the earth during the 'Reign of Love', so it happens according to them in the
body. Now it is impossible that the parts should be united together when they come into being and should
come from different parts of the parent, meeting together in one place. Then how can the upper and lower,
right and left, front and back parts have been 'sundered'? All these points are unintelligible. Further, some
parts are distinguished by possessing a faculty, others by being in certain states or conditions; the
heterogeneous, as tongue and hand, by the faculty of doing something, the homogeneous by hardness and
softness and the other similar states. Blood, then, will not be blood, nor flesh flesh, in any and every state. It
is clear, then, that that which comes from any part, as blood from blood or flesh from flesh, will not be
identical with that part. But if it is something different from which the blood of the offspring comes, the
coming of the semen from all the parts will not be the cause of the resemblance, as is held by the supporters
of this theory. For if blood is formed from something which is not blood, it is enough that the semen come
from one part only, for why should not all the other parts of the offspring as well as blood be formed from
one part of the parent? Indeed, this theory seems to be the same as that of Anaxagoras, that none of the
homogeneous parts come into being, except that these theorists assume, in the case of the generation of
animals, what he assumed of the universe.

Then, again, how will these parts that came from all the body of the parent be increased or grow? It is true
that Anaxagoras plausibly says that particles of flesh out of the food are added to the flesh. But if we do not
say this (while saying that semen comes from all parts of the body), how will the foetus become greater by
the addition of something else if that which is added remain unchanged? But if that which is added can
change, then why not say that the semen from the very first is of such a kind that blood and flesh can be made
out of it, instead of saying that it itself is blood and flesh? Nor is there any other alternative, for surely we
cannot say that it is increased later by a process of mixing, as wine when water is poured into it. For in that
case each element of the mixture would be itself at first while still unmixed, but the fact rather is that flesh
and bone and each of the other parts is such later. And to say that some part of the semen is sinew and bone is
quite above us, as the saying is.

Besides all this there is a difficulty if the sex is determined in conception (as Empedocles says: 'it is shed in
clean vessels; some wax female, if they fall in with cold'). Anyhow, it is plain that both men and women
change not only from infertile to fertile, but also from bearing female to bearing male offspring, which looks
as if the cause does not lie in the semen coming from all the parent or not, but in the mutual proportion or
disproportion of that comes from the woman and the man, or in something of this kind. It is clear, then, if we
are to put this down as being so, that the female sex is not determined by the semen coming from any

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ON THE GENERATION OF ANIMALS

particular part, and consequently neither is the special sexual part so determined (if really the same semen can
become either male or female child, which shows that the sexual part does not exist in the semen). Why, then,
should we assert this of this part any more than of others? For if semen does not come from this part, the
uterus, the same account may be given of the others.

Again, some creatures come into being neither from parents of the same kind nor from parents of a different
kind, as flies and the various kinds of what are called fleas; from these are produced animals indeed, but not
in this case of similar nature but a kind of scolex. It is plain in this case that the young of a different kind are
not produced by semen coming from all parts of the parent, for they would then resemble them, if indeed
resemblance is a sign of its coming from all parts.

Further even among animals some produce many young from a single coition (and something like this is
universal among plants, for it is plain that they bear all the fruit of a whole season from a single movement).
And yet how would this be possible if the semen were secreted from all the body? For from a single coition
and a single segregation of the semen scattered throughout the body must needs follow only a single
secretion. Nor is it possible for it to be separated in the uterus, for this would no longer be a mere separation
of semen, but, as it were, a severance from a new plant or animal.

Again, the cuttings from a plant bear seed; clearly, therefore, even before they were cut from the parent plant,
they bore their fruit from their own mass alone, and the seed did not come from all the plant.

But the greatest proof of all is derived from observations we have sufficiently established on insects. For, if
not in all, at least in most of these, the female in the act of copulation inserts a part of herself into the male.
This, as we said before, is the way they copulate, for the females manifestly insert this from below into the
males above, not in all cases, but in most of those observed. Hence it seems clear that, when the males do
emit semen, then also the cause of the generation is not its coming from all the body, but something else
which must be investigated hereafter. For even if it were true that it comes from all the body, as they say,
they ought not to claim that it comes from all parts of it, but only from the creative part- from the workman,
so to say, not the material he works in. Instead of that, they talk as if one were to say that the semen comes
from the shoes, for, generally speaking, if a son is like his father, the shoes he wears are like his father's
shoes.

As to the vehemence of pleasure in sexual intercourse, it is not because the semen comes from all the body,
but because there is a strong friction (wherefore if this intercourse is often repeated the pleasure is diminished
in the persons concerned). Moreover, the pleasure is at the end of the act, but it ought, on the theory, to be in
each of the parts, and not at the same time, but sooner in some and later in others.

If mutilated young are born of mutilated parents, it is for the same reason as that for which they are like them.
And the young of mutilated parents are not always mutilated, just as they are not always like their parents; the
cause of this must be inquired into later, for this problem is the same as that.

Again, if the female does not produce semen, it is reasonable to suppose it does not come from all the body of
the male either. Conversely, if it does not come from all the male it is not unreasonable to suppose that it does
not come from the female, but that the female is cause of the generation in some other way. Into this we must
next inquire, since it is plain that the semen is not secreted from all the parts.

In this investigation and those which follow from it, the first thing to do is to understand what semen is, for
then it will be easier to inquire into its operations and the phenomena connected with it. Now the object of
semen is to be of such a nature that from it as their origin come into being those things which are naturally
formed, not because there is any agent which makes them from it as simply because this is the semen. Now
we speak of one thing coming from another in many senses; it is one thing when we say that night comes

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ON THE GENERATION OF ANIMALS

from day or a man becomes man from boy, meaning that A follows B; it is another if we say that a statue is
made from bronze and a bed from wood, and so on in all the other cases where we say that the thing made is
made from a material, meaning that the whole is formed from something preexisting which is only put into
shape. In a third sense a man becomes unmusical from being musical, sick from being well, and generally in
this sense contraries arise from contraries. Fourthly, as in the 'climax' of Epicharmus; thus from slander
comes railing and from this fighting, and all these are from something in the sense that it is the efficient
cause. In this last class sometimes the efficient cause is in the things themselves, as in the last mentioned (for
the slander is apart of the whole trouble), and sometimes external, as the art is external to the work of art or
the torch to the burning house. Now the offspring comes from the semen, and it is plainly in one of the two
following senses that it does so- either the semen is the material from which it is made, or it is the first
efficient cause. For assuredly it is not in the sense of A being after B, as the voyage comes from, i.e. after, the
Panathenaea; nor yet as contraries come from contraries, for then one of the two contraries ceases to be, and a
third substance must exist as an immediate underlying basis from which the new thing comes into being. We
must discover then, in which of the two other classes the semen is to be put, whether it is to be regarded as
matter, and therefore acted upon by something else, or as a form, and therefore acting upon something else,
or as both at once. For perhaps at the same time we shall see clearly also how all the products of semen come
into being from contraries, since coming into being from contraries is also a natural process, for some animals
do so, i.e. from male and female, others from only one parent, as is the case with plants and all those animals
in which male and female are not separately differentiated. Now that which comes from the generating parent
is called the seminal fluid, being that which first has in it a principle of generation, in the case of all animals
whose nature it is to unite; semen is that which has in it the principles from both united parents, as the first
mixture which arises from the union of male and female, be it a foetus or an ovum, for these already have in
them that which comes from both. (Semen, or seed, and grain differ only in the one being earlier and the
other later, grain in that it comes from something else, i.e. the seed, and seed in that something else, the grain,
comes from it, for both are really the same thing.)

We must again take up the question what the primary nature of what is called semen is. Needs must
everything which we find in the body either be (1) one of the natural parts, whether homogeneous or
heterogeneous, or (2) an unnatural part such as a growth, or (3) a secretion or excretion, or (4) waste-product,
or (5) nutriment. (By secretion or excretion I mean the residue of the nutriment, by waste-product that which
is given off from the tissues by an unnatural decomposition.)

Now that semen cannot be a part of the body is plain, for it is homogeneous, and from the homogeneous
nothing is composed, e.g. from only sinew or only flesh; nor is it separated as are all the other parts. But
neither is it contrary to Nature nor a defect, for it exists in all alike, and the development of the young animal
comes from it. Nutriment, again, is obviously introduced from without.

It remains, then, that it must be either a waste-product or a secretion or excretion. Now the ancients seem to
think that it is a waste-product, for when they say that it comes from all the body by reason of the heat of the
movement of the body in copulation, they imply that it is a kind of waste-product. But these are contrary to
Nature, and from such arises nothing according to Nature. So then it must be a secretion or excretion.

But, to go further into it, every secretion or excretion is either of useless or useful nutriment; by 'useless' I
mean that from which nothing further is contributed to natural growth, but which is particularly mischievous
to the body if too much of it is consumed; by 'useful' I mean the opposite. Now it is evident that it cannot be
of the former character, for such is most abundant in persons of the worst condition of body through age or
sickness; semen, on the contrary, is least abundant in them for either they have none at all or it is not fertile,
because a useless and morbid secretion is mingled with it.

Semen, then, is part of a useful secretion. But the most useful is the last and that from which finally is formed
each of the parts of the body. For secretions are either earlier or later; of the nutriment in the first stage the

18 13

ON THE GENERATION OF ANIMALS

secretion is phlegm and the like, for phlegm also is a secretion of the useful nutriment, an indication of this
being that if it is mixed with pure nutriment it is nourishing, and that it is used up in cases of illness. The final
secretion is the smallest in proportion to the quantity of nutriment. But we must reflect that the daily
nutriment by which animals and plants grow is but small, for if a very little be added continually to the same
thing the size of it will become excessive.

So we must say the opposite of what the ancients said. For whereas they said that semen is that which comes
from all the body, we shall say it is that whose nature is to go to all of it, and what they thought a
waste-product seems rather to be a secretion. For it is more reasonable to suppose that the last extract of the
nutriment which goes to all parts resembles that which is left over from it, just as part of a painter's colour is
often left over resembling that which he has used up. Waste-products, on the contrary, are always due to
corruption or decay and to a departure from Nature.

A further proof that it is not a waste-product, but rather a secretion, is the fact that the large animals have few
young, the small many. For the large must have more waste and less secretion, since the great size of the
body causes most of the nutriment to be used up, so that the residue or secretion is small.

Again, no place has been set apart by Nature for waste-products but they flow wherever they can find an
easy passage in the body, but a place has been set apart for all the natural secretions; thus the lower intestine
serves for the excretion of the solid nutriment, the bladder for that of the liquid; for the useful part of the
nutriment we have the upper intestine, for the spermatic secretions the uterus and pudenda and breasts, for it
is collected and flows together into them.

And the resulting phenomena are evidence that semen is what we have said, and these result because such is
the nature of the secretion. For the exhaustion consequent on the loss of even a very little of the semen is
conspicuous because the body is deprived of the ultimate gain drawn from the nutriment. With some few
persons, it is true, during a short time in the flower of their youth the loss of it, if it be excessive in quantity,
is an alleviation (just as in the case of the nutriment in its first stage, if too much have been taken, since
getting rid of this also makes the body more comfortable), and so it may be also when other secretions come
away with it, for in that case it is not only semen that is lost but also other influences come away mingled
with it, and these are morbid. Wherefore, with some men at least, that which comes from them proves
sometimes incapable of procreation because the seminal element in it is so small. But still in most men and as
a general rule the result of intercourse is exhaustion and weakness rather than relief, for the reason given.
Moreover, semen does not exist in them either in childhood or in old age or in sickness- in the last case
because of weakness, in old age because they do not sufficiently concoct their food, and in childhood because
they are growing and so all the nutriment is used up too soon, for in about five years, in the case of human
beings at any rate, the body seems to gain half the height that is gained in all the rest of life.

In many animals and plants we find a difference in this connexion not only between kinds as compared with
kinds, but also between similar individuals of the same kind as compared with each other, e.g. man with man
or vine with vine. Some have much semen, others little, others again none at all, not through weakness but
the contrary, at any rate in some cases. This is because the nutriment is used up to form the body, as with
some human beings, who, being in good condition and developing much flesh or getting rather too fat,
produce less semen and are less desirous of intercourse. Like this is what happens with those vines which
'play the goat', that is, luxuriate wantonly through too much nutrition, for he-goats when fat are less inclined
to mount the female; for which reason they thin them before breeding from them, and say that the vines 'play
the goat', so calling it from the condition of the goats. And fat people, women as well as men, appear to be
less fertile than others from the fact that the secretion when in process of concoction turns to fat with those
who are too well-nourished. For fat also is a healthy secretion due to good living.

18 14

ON THE GENERATION OF ANIMALS

In some cases no semen is produced at all, as by the willow and poplar. This condition is due to each of the
two causes, weakness and strength; the former prevents concoction of the nutriment, the latter causes it to be
all consumed, as said above. In like manner other animals produce much semen through weakness as well as
through strength, when a great quantity of a useless secretion is mixed with it; this sometimes results in actual
disease when a passage is not found to carry off the impurity, and though some recover of this, others actually
die of it. For corrupt humours collect here as in the urine, which also has been known to cause disease.

[Further the same passage serves for urine and semen; and whatever animals have both kinds of excrement,
that of liquid and that of solid nutriment, discharge the semen by the same passage as the liquid excrement
(for it is a secretion of a liquid, since the nutriment of all animals is rather liquid than solid), but those which
have no liquid excrement discharge it at the passage of the solid residua. Moreover, waste-products are
always morbid, but the removal of the secretion is useful; now the discharge of the semen participates in both
characteristics because it takes up some of the non-useful nutriment. But if it were a waste-product it would
be always harmful; as it is, it is not so.]

From what has been said, it is clear that semen is a secretion of useful nutriment, and that in its last stage,
whether it is produced by all or no.

After this we must distinguish of what sort of nutriment it is a secretion, and must discuss the catamenia
which occur in certain of the vivipara. For thus we shall make it clear (1) whether the female also produces
semen like the male and the foetus is a single mixture of two semens, or whether no semen is secreted by the
female, and, (2) if not, whether she contributes nothing else either to generation but only provides a
receptacle, or whether she does contribute something, and, if so, how and in what manner she does so.

We have previously stated that the final nutriment is the blood in the sanguinea and the analogous fluid in the
other animals. Since the semen is also a secretion of the nutriment, and that in its final stage, it follows that it
will be either (1) blood or that which is analogous to blood, or (2) something formed from this. But since it is
from the blood, when concocted and somehow divided up, that each part of the body is made, and since the
semen if properly concocted is quite of a different character from the blood when it is separated from it, but if
not properly concocted has been known in some cases to issue in a bloody condition if one forces oneself too
often to coition, therefore it is plain that semen will be a secretion of the nutriment when reduced to blood,
being that which is finally distributed to the parts of the body. And this is the reason why it has so great
power, for the loss of the pure and healthy blood is an exhausting thing; for this reason also it is natural that
the offspring should resemble the parents, for that which goes to all the parts of the body resembles that
which is left over. So that the semen which is to form the hand or the face or the whole animal is already the
hand or face or whole animal undifferentiated, and what each of them is actually such is the semen
potentially, either in virtue of its own mass or because it has a certain power in itself. I mention these
alternatives here because we have not yet made it clear from the distincti;lH the vivipara. For thus we shall
make it clear (1) ons drawn hitherto whether it is the matter of the semen that is the cause of generation, or
whether it has in it some faculty and efficient cause thereof, for the hand also or any other bodily part is not
hand or other part in a true sense if it be without soul or some other power, but is only called by the same
name as the living hand.

On this subject, then, so much may be laid down. But since it is necessary (1) that the weaker animal also
should have a secretion greater in quantity and less concocted, and (2) that being of such a nature it should be
a mass of sanguineous liquid, and (3) since that which Nature endows with a smaller portion of heat is
weaker, and (4) since it has already been stated that such is the character of the female- putting all these
considerations together we see that the sanguineous matter discharged by the female is also a secretion. And

19 15

ON THE GENERATION OF ANIMALS

such is the discharge of the so-called catamenia.

It is plain, then, that the catamenia are a secretion, and that they are analogous in females to the semen in
males. The circumstances connected with them are evidence that this view is correct. For the semen begins to
appear in males and to be emitted at the same time of life that the catamenia begin to flow in females, and
that they change their voice and their breasts begin to develop. So, too, in the decline of life the generative
power fails in the one sex and the catamenia in the other.

The following signs also indicate that this discharge in females is a secretion. Generally speaking women
suffer neither from haemorrhoids nor bleeding at the nose nor anything else of the sort except when the
catamenia are ceasing, and if anything of the kind occurs the flow is interfered with because the discharge is
diverted to it.

Further, the blood-vessels of women stand out less than those of men, and women are rounder and smoother
because the secretion which in men goes to these vessels is drained away with the catamenia. We must
suppose, too, that the same cause accounts for the fact that the bulk of the body is smaller in females than in
males among the vivipara, since this is the only class in which the catamenia are discharged from the body.
And in this class the fact is clearest in women, for the discharge is greater in women than in the other
animals. Wherefore her pallor and the absence of prominent blood-vessels is most conspicuous, and the
deficient development of her body compared with a man's is obvious.

Now since this is what corresponds in the female to the semen in the male, and since it is not possible that
two such discharges should be found together, it is plain that the female does not contribute semen to the
generation of the offspring. For if she had semen she would not have the catamenia; but, as it is, because she
has the latter she has not the former.

It has been stated then that the catamenia are a secretion as the semen is, and confirmation of this view may
be drawn from some of the phenomena of animals. For fat creatures produce less semen than lean ones, as
observed before. The reason is that fat also, like semen, is a secretion, is in fact concocted blood, only not
concocted in the same way as the semen. Thus, if the secretion is consumed to form fat the semen is naturally
deficient. And so among the bloodless animals the cephalopoda and Crustacea are in best condition about the
time of producing eggs, for, because they are bloodless and no fat is formed in them, that which is analogous
in them to fat is at that season drawn off to form the spermatic secretion.

And a proof that the female does not emit similar semen to the male, and that the offspring is not formed by a
mixture of both, as some say, is that often the female conceives without the sensation of pleasure in
intercourse, and if again the pleasure is experience by her no less than by the male and the two sexes reach
their goal together, yet often no conception takes place unless the liquid of the so-called catamenia is present
in a right proportion. Hence the female does not produce young if the catamenia are absent altogether, nor
often when, they being present, the efflux still continues; but she does so after the purgation. For in the one
case she has not the nutriment or material from which the foetus can be framed by the power coming from the
male and inherent in the semen, and in the other it is washed away with the catamenia because of their
abundance. But when after their occurrence the greater part has been evacuated, the remainder is formed into
a foetus. Cases of conception when the catamenia do not occur at all, or of conception during their discharge
instead of after it, are due to the fact that in the former instance there is only so much liquid to begin with as
remains behind after the discharge in fertile women, and no greater quantity is secreted so as to come away
from the body, while in the latter instance the mouth of the uterus closes after the discharge. When, therefore,
the quantity already expelled from the body is great but the discharge still continues, only not on such a scale
as to wash away the semen, then it is that conception accompanies coition. Nor is it at all strange that the
catamenia should still continue after conception (for even after it they recur to some extent, but are scanty and
do not last during all the period of gestation; this, however, is a morbid phenomenon, wherefore it is found

19 16

ON THE GENERATION OF ANIMALS

only in a few cases and then seldom, whereas it is that which happens as a regular thing that is according to
Nature).

It is clear then that the female contributes the material for generation, and that this is in the substance of the
catamenia, and that they are a secretion.

Some think that the female contributes semen in coition because the pleasure she experiences is sometimes
similar to that of the male, and also is attended by a liquid discharge. But this discharge is not seminal; it is
merely proper to the part concerned in each case, for there is a discharge from the uterus which occurs in
some women but not in others. It is found in those who are fair-skinned and of a feminine type generally, but
not in those who are dark and of a masculine appearance. The amount of this discharge, when it occurs, is
sometimes on a different scale from the emission of semen and far exceeds it. Moreover, different kinds of
food cause a great difference in the quantity of such discharges; for instance some pungently-flavoured foods
cause them to be conspicuously increased. And as to the pleasure which accompanies coition it is due to
emission not only of semen, but also of a spiritus, the coming together of which precedes the emission. This
is plain in the case of boys who are not yet able to emit semen, but are near the proper age, and of men who
are impotent, for all these are capable of pleasure by attrition. And those who have been injured in the
generative organs sometimes suffer from diarrhoea because the secretion, which they are not able to concoct
and turn into semen, is diverted into the intestine. Now a boy is like a woman in form, and the woman is as it
were an impotent male, for it is through a certain incapacity that the female is female, being incapable of
concocting the nutriment in its last stage into semen (and this is either blood or that which is analogous to it
in animals which are bloodless owing to the coldness of their nature). As then diarrhoea is caused in the
bowels by the insufficient concoction of the blood, so are caused in the blood-vessels all discharges of blood,
including that of the catamenia, for this also is such a discharge, only it is natural whereas the others are
morbid.

Thus it is clear that it is reasonable to suppose that generation comes from this. For the catamenia are semen
not in a pure state but in need of working up, as in the formation of fruits the nutriment is present, when it is
not yet sifted thoroughly, but needs working up to purify it. Thus the catamenia cause generation mixture
with the semen, as this impure nutriment in plants is nutritious when mixed with pure nutriment.

And a sign that the female does not emit semen is the fact that the pleasure of intercourse is caused by touch
in the same region of the female as of the male; and yet is it not from thence that this flow proceeds. Further,
it is not all females that have it at all, but only the sanguinea, and not all even of these, but only those whose
uterus is not near the hypozoma and which do not lay eggs; it is not found in the animals which have no
blood but only the analogous fluid (for what is blood in the former is represented by another fluid in the
latter). The reason why neither the latter nor those sanguinea mentioned (i.e. those whose uterus is low and
which do not lay eggs) have this effluxion is the dryness of their bodies; this allows but little matter to be
secreted, only enough for generation but not enough to be discharged from the body. All animals that are
viviparous without producing eggs first (such are man and all quadrupeds which bend their hind-legs
outwards, for all these are viviparous without producing eggs)- all these have the catamenia, unless they are
defective in development as the mule, only the efflux is not abundant as in women. Details of the facts in
each animal have been given in the Enquiries concerning animals.

The catamenia are more abundant in women than in the other animals, and men emit the most semen in
proportion to their size. The reason is that the composition of their bodies is liquid and hot compared to
others, for more matter must be secreted in such a case. Further, man has no such parts in his body as those to
which the superfluous matter is diverted in the other animals; for he has no great quantity of hair in

20 17

ON THE GENERATION OF ANIMALS

proportion to his body, nor outgrowths of bones, horns, and teeth.

There is evidence that the semen is in the catamenia, for, as said before, this secretion appears in the male at
the same time of life as the catamenia in the female; this indicates that the parts destined to receive each of
these secretions are differentiated at the same time in both sexes; and as the neighboring parts in both become
swollen the hair of puberty springs forth in both alike. As the parts in question are on the point of
differentiating they are distended by the spiritus; this is clearer in males in the testes, but appears also about
the breasts; in females it is more marked in the breasts, for it is when they have risen two fingers' breadth that
the catamenia generally begin.

Now, in all living things in which the male and female are not separated the semen (or seed) is a sort of
embryo; by embryo I mean the first mixture of male and female; hence, from one semen comes one bodys-
for example, one stalk of wheat from one grain, as one animal from one egg (for twin eggs are really two
eggs). But in whatever kinds the sexes are distinguished, in these many animals may come from one emission
of semen, showing that the semen differs in its nature in plants and animals. A proof of this is that animals
which can bear more than one young one at a time do so in consequence of only one coition. Whereby, too, it
is plain that the semen does not come from the whole of the body; for neither would on to their size. The
reason is that the composition of thei2J the different parts of the semen already be separated as soon as
discharged from the same part, nor could they be separated in the uterus if they had once entered it all
together; but what does happen is just what one would expect, since what the male contributes to generation
is the form and the efficient cause, while the female contributes the material. In fact, as in the coagulation of
milk, the milk being the material, the fig-juice or rennet is that which contains the curdling principle, so acts
the secretion of the male, being divided into parts in the female. Why it is sometimes divided into more or
fewer parts, and sometimes not divided at all, will be the subject of another discussion. But because it does
not differ in kind at any rate this does not matter, but what does matter is only that each part should
correspond to the material, being neither too little to concoct it and fix it into form, nor too much so as to dry
it up; it then generates a number of offspring. But from this first formative semen, if it remains one, and is not
divided, only one young one comes into being.

That, then, the female does not contribute semen to generation, but does contribute something, and that this is
the matter of the catamenia, or that which is analogous to it in bloodless animals, is clear from what has been
said, and also from a general and abstract survey of the question. For there must needs be that which
generates and that from which it generates; even if these be one, still they must be distinct in form and their
essence must be different; and in those animals that have these powers separate in two sexes the body and
nature of the active and the passive sex must also differ. If, then, the male stands for the effective and active,
and the female, considered as female, for the passive, it follows that what the female would contribute to the
semen of the male would not be semen but material for the semen to work upon. This is just what we find to
be the case, for the catamenia have in their nature an affinity to the primitive matter.

So much for the discussion of this question. At the same time the answer to the next question we have to
investigate is clear from these considerations, I mean how it is that the male contributes to generation and
how it is that the semen from the male is the cause of the offspring. Does it exist in the body of the embryo as
a part of it from the first, mingling with the material which comes from the female? Or does the semen
communicate nothing to the material body of the embryo but only to the power and movement in it? For this
power is that which acts and makes, while that which is made and receives the form is the residue of the
secretion in the female. Now the latter alternative appears to be the right one both a priori and in view of the
facts. For, if we consider the question on general grounds, we find that, whenever one thing is made from two
of which one is active and the other passive, the active agent does not exist in that which is made; and, still

21 18

ON THE GENERATION OF ANIMALS

more generally, the same applies when one thing moves and another is moved; the moving thing does not
exist in that which is moved. But the female, as female, is passive, and the male, as male, is active, and the
principle of the movement comes from him. Therefore, if we take the highest genera under which they each
fall, the one being active and motive and the other passive and moved, that one thing which is produced
comes from them only in the sense in which a bed comes into being from the carpenter and the wood, or in
which a ball comes into being from the wax and the form. It is plain then that it is not necessary that anything
at all should come away from the male, and if anything does come away it does not follow that this gives rise
to the embryo as being in the embryo, but only as that which imparts the motion and as the form; so the
medical art cures the patient.

This a priori argument is confirmed by the facts. For it is for this reason that some males which unite with the
female do not, it appears, insert any part of themselves into the female, but on the contrary the female inserts
a part of herself into the male; this occurs in some insects. For the effect produced by the semen in the female
(in the case of those animals whose males do insert a part) is produced in the case of these insects by the heat
and power in the male animal itself when the female inserts that part of herself which receives the secretion.
And therefore such animals remain united a long time, and when they are separated the young are produced
quickly. For the union lasts until that which is analogous to the semen has done its work, and when they
separate the female produces the embryo quickly; for the young is imperfect inasmuch as all such creatures
give birth to scoleces.

What occurs in birds and oviparous fishes is the greatest proof that neither does the semen come from all
parts of the male nor does he emit anything of such a nature as to exist within that which is generated, as part
of the material embryo, but that he only makes a living creature by the power which resides in the semen (as
we said in the case of those insects whose females insert a part of themselves into the male). For if a hen-bird
is in process of producing wind-eggs and is then trodden by the cock before the egg has begun to whiten and
while it is all still yellow, then they become fertile instead of being wind-eggs. And if while it is still yellow
she be trodden by another cock, the whole brood of chicks turn out like the second cock. Hence some of those
who are anxious to rear fine birds act thus; they change the cocks for the first and second treading, not as if
they thought that the semen is mingled with the egg or exists in it, or that it comes from all parts of the cock;
for if it did it would have come from both cocks, so that the chick would have all its parts doubled. But it is
by its force that the semen of the male gives a certain quality to the material and the nutriment in the female,
for the second semen added to the first can produce this effect by heat and concoction, as the egg acquires
nutriment so long as it is growing.

The same conclusion is to be drawn from the generation of oviparous fishes. When the female has laid her
eggs, the male spinkles the milt over them, and those eggs are fertilized which it reaches, but not the others;
this shows that the male does not contribute anything to the quantity but only to the quality of the embryo.

From what has been said it is plain that the semen does not come from the whole of the body of the male in
those animals which emit it, and that the contribution of the female to the generative product is not the same
as that of the male, but the male contributes the principle of movement and the female the material. This is
why the female does not produce offspring by herself, for she needs a principle, i.e. something to begin the
movement in the embryo and to define the form it is to assume. Yet in some animals, as birds, the nature of
the female unassisted can generate to a certain extent, for they do form something, only it is incomplete; I
mean the so-called wind-eggs.

For the same reason the development of the embryo takes place in the female; neither the male himself nor
the female emits semen into the male, but the female receives within herself the share contributed by both,

22 19

ON THE GENERATION OF ANIMALS

because in the female is the material from which is made the resulting product. Not only must the mass of
material exist there from which the embryo is formed in the first instance, but further material must
constantly be added that it may increase in size. Therefore the birth must take place in the female. For the
carpenter must keep in close connexion with his timber and the potter with his clay, and generally all
workmanship and the ultimate movement imparted to matter must be connected with the material concerned,
as, for instance, architecture is in the buildings it makes.

From these considerations we may also gather how it is that the male contributes to generation. The male
does not emit semen at all in some animals, and where he does this is no part of the resulting embryo; just so
no material part comes from the carpenter to the material, i.e. the wood in which he works, nor does any part
of the carpenter's art exist within what he makes, but the shape and the form are imparted from him to the
material by means of the motion he sets up. It is his hands that move his tools, his tools that move the
material; it is his knowledge of his art, and his soul, in which is the form, that moves his hands or any other
part of him with a motion of some definite kind, a motion varying with the varying nature of the object made.
In like manner, in the male of those animals which emit semen Nature uses the semen as a tool and as
possessing motion in actuality, just as tools are used in the products of any art, for in them lies in a certain
sense the motion of the art. Such, then, is the way in which these males contribute to generation. But when
the male does not emit semen, but the female inserts some part of herself into the male, this is parallel to a
case in which a man should carry the material to the workman. For by reason of weakness in such males
Nature is not able to do anything by any secondary means, but the movements imparted to the material are
scarcely strong enough when Nature herself watches over them. Thus here she resembles a modeller in clay
rather than a carpenter, for she does not touch the work she is forming by means of tools, but, as it were, with
her own hands.

In all animals which can move about, the sexes are separated, one individual being male and one female,
though both are the same in species, as with man and horse. But in plants these powers are mingled, female
not being separated from male. Wherefore they generate out of themselves, and do not emit semen but
produce an embryo, what is called the seed. Empedocles puts this well in the line: 'and thus the tall trees
oviposit; first olives...' For as the egg is an embryo, a certain part of it giving rise to the animal and the rest
being nutriment, so also from a part of the seed springs the growing plant, and the rest is nutriment for the
shoot and the first root.

In a certain sense the same thing happens also in those animals which have the sexes separate. For when there
is need for them to generate the sexes are no longer separated any more than in plants, their nature desiring
that they shall become one; and this is plain to view when they copulate and are united, that one animal is
made out of both.

It is the nature of those creatures which do not emit semen to remain united a long time until the male
element has formed the embryo, as with those insects which copulate. The others so remain only until the
male has discharged from the parts of himself introduced something which will form the embryo in a longer
time, as among the sanguinea. For the former remain paired some part of a day, while the semen forms the
embryo in several days. And after emitting this they cease their union.

And animals seem literally to be like divided plants, as though one should separate and divide them, when
they bear seed, into the male and female existing in them.

In all this Nature acts like an intelligent workman. For to the essence of plants belongs no other function or
business than the production of seed; since, then, this is brought about by the union of male and female,

23 20

ON THE GENERATION OF ANIMALS

Nature has mixed these and set them together in plants, so that the sexes are not divided in them. Plants,
however, have been investigated elsewhere. But the function of the animal is not only to generate (which is
common to all living things), but they all of them participate also in a kind of knowledge, some more and
some less, and some very little indeed. For they have sense-perception, and this is a kind of knowledge. (If
we consider the value of this we find that it is of great importance compared with the class of lifeless objects,
but of little compared with the use of the intellect. For against the latter the mere participation in touch and
taste seems to be practically nothing, but beside absolute insensibility it seems most excellent; for it would
seem a treasure to gain even this kind of knowledge rather than to lie in a state of death and non-existence.)
Now it is by sense-perception that an animal differs from those organisms which have only life. But since, if
it is a living animal, it must also live; therefore, when it is necessary for it to accomplish the function of that
which has life, it unites and copulates, becoming like a plant, as we said before.

Testaceous animals, being intermediate between animals and plants, perform the function of neither class as
belonging to both. As plants they have no sexes, and one does not generate in another; as animals they do not
bear fruit from themselves like plants; but they are formed and generated from a liquid and earthy concretion.
However, we must speak later of the generation of these animals.

Book II

THAT the male and the female are the principles of generation has been previously stated, as also what is
their power and their essence. But why is it that one thing becomes and is male, another female? It is the
business of our discussion as it proceeds to try and point out (1) that the sexes arise from Necessity and the
first efficient cause, (2) from what sort of material they are formed. That (3) they exist because it is better and
on account of the final cause, takes us back to a principle still further remote.

Now (1) some existing things are eternal and divine whilst others admit of both existence and non-existence.
But (2) that which is noble and divine is always, in virtue of its own nature, the cause of the better in such
things as admit of being better or worse, and what is not eternal does admit of existence and non-existence,
and can partake in the better and the worse. And (3) soul is better than body, and living, having soul, is
thereby better than the lifeless which has none, and being is better than not being, living than not living.
These, then, are the reasons of the generation of animals. For since it is impossible that such a class of things
as animals should be of an eternal nature, therefore that which comes into being is eternal in the only way
possible. Now it is impossible for it to be eternal as an individual (though of course the real essence of things
is in the individual)- were it such it would be eternal- but it is possible for it as a species. This is why there is
always a class of men and animals and plants. But since the male and female essences are the first principles
of these, they will exist in the existing individuals for the sake of generation. Again, as the first efficient or
moving cause, to which belong the definition and the form, is better and more divine in its nature than the
material on which it works, it is better that the superior principle should be separated from the inferior.
Therefore, wherever it is possible and so far as it is possible, the male is separated from the female. For the
first principle of the movement, or efficient cause, whereby that which comes into being is male, is better and
more divine than the material whereby it is female. The male, however, comes together and mingles with the
female for the work of generation, because this is common to both.

A thing lives, then, in virtue of participating in the male and female principles, wherefore even plants have
some kind of life; but the class of animals exists in virtue of sense-perception. The sexes are divided in
nearly all of these that can move about, for the reasons already stated, and some of them, as said before, emit
semen in copulation, others not. The reason of this is that the higher animals are more independent in their
nature, so that they have greater size, and this cannot exist without vital heat; for the greater body requires

Book II 21

ON THE GENERATION OF ANIMALS

more force to move it, and heat is a motive force. Therefore, taking a general view, we may say that
sanguinea are of greater size than bloodless animals, and those which move about than those which remain
fixed. And these are just the animals which emit semen on account of their heat and size.

So much for the cause of the existence of the two sexes. Some animals bring to perfection and produce into
the world a creature like themselves, as all those which bring their young into the world alive; others produce
something undeveloped which has not yet acquired its own form; in this latter division the sanguinea lay
eggs, the bloodless animals either lay an egg or give birth to a scolex. The difference between egg and scolex
is this: an egg is that from a part of which the young comes into being, the rest being nutriment for it; but the
whole of a scolex is developed into the whole of the young animal. Of the vivipara, which bring into the
world an animal like themselves, some are internally viviparous (as men, horses, cattle, and of marine
animals dolphins and the other cetacea); others first lay eggs within themselves, and only after this are
externally viviparous (as the cartilaginous fishes). Among the ovipara some produce the egg in a perfect
condition (as birds and all oviparous quadrupeds and footless animals, e.g. lizards and tortoises and most
snakes; for the eggs of all these do not increase when once laid). The eggs of others are imperfect; such are
those of fishes, crustaceans, and cephalopods, for their eggs increase after being produced.

All the vivipara are sanguineous, and the sanguinea are either viviparous or oviparous, except those which are
altogether infertile. Among bloodless animals the insects produce a scolex, alike those that are generated by
copulation and those that copulate themselves though not so generated. For there are some insects of this sort,
which though they come into being by spontaneous generation are yet male and female; from their union
something is produced, only it is imperfect; the reason of this has been previously stated.

These classes admit of much cross-division. Not all bipeds are viviparous (for birds are oviparous), nor are
they all oviparous (for man is viviparous), nor are all quadrupeds oviparous (for horses, cattle, and countless
others are viviparous), nor are they all viviparous (for lizards, crocodiles, and many others lay eggs). Nor
does the presence or absence of feet make the difference between them, for not only are some footless
animals viviparous, as vipers and the cartilaginous fishes, while others are oviparous, as the other fishes and
serpents, but also among those which have feet many are oviparous and many viviparous, as the quadrupeds
above mentioned. And some which have feet, as man, and some which have not, as the whale and dolphin,
are internally viviparous. By this character then it is not possible to divide them, nor is any of the locomotive
organs the cause of this difference, but it is those animals which are more perfect in their nature and
participate in a purer element which are viviparous, for nothing is internally viviparous unless it receive and
breathe out air. But the more perfect are those which are hotter in their nature and have more moisture and are
not earthy in their composition. And the measure of natural heat is the lung when it has blood in it, for
generally those animals which have a lung are hotter than those which have not, and in the former class again
those whose lung is not spongy nor solid nor containing only a little blood, but soft and full of blood. And as
the animal is perfect but the egg and the scolex are imperfect, so the perfect is naturally produced from the
more perfect. If animals are hotter as shown by their possessing a lung but drier in their nature, or are colder
but have more moisture, then they either lay a perfect egg or are viviparous after laying an egg within
themselves. For birds and scaly reptiles because of their heat produce a perfect egg, but because of their
dryness it is only an egg; the cartilaginous fishes have less heat than these but more moisture, so that they are
intermediate, for they are both oviparous and viviparous within themselves, the former because they are cold,
the latter because of their moisture; for moisture is vivifying, whereas dryness is furthest removed from what
has life. Since they have neither feathers nor scales such as either reptiles or other fishes have, all which are
signs rather of a dry and earthy nature, the egg they produce is soft; for the earthy matter does not come to the
surface in their eggs any more than in themselves. This is why they lay eggs in themselves, for if the egg
were laid externally it would be destroyed, having no protection.

Animals that are cold and rather dry than moist also lay eggs, but the egg is imperfect; at the same time,
because they are of an earthy nature and the egg they produce is imperfect, therefore it has a hard integument

Book II 22

ON THE GENERATION OF ANIMALS

that it may be preserved by the protection of the shell-like covering. Hence fishes, because they are scaly,
and Crustacea, because they are of an earthy nature, lay eggs with a hard integument.

The cephalopods, having themselves bodies of a sticky nature, preserve in the same way the imperfect eggs
they lay, for they deposit a quantity of sticky material about the embryo. All insects produce a scolex. Now
all the insects are bloodless, wherefore all creatures that produce a scolex from themselves are so. But we
cannot say simply that all bloodless animals produce a scolex, for the classes overlap one another, (1) the
insects, (2) the animals that produce a scolex, (3) those that lay their egg imperfect, as the scaly fishes, the
Crustacea, and the cephalopoda. I say that these form a gradation, for the eggs of these latter resemble a
scolex, in that they increase after oviposition, and the scolex of insects again as it develops resembles an egg;
how so we shall explain later.

We must observe how rightly Nature orders generation in regular gradation. The more perfect and hotter
animals produce their young perfect in respect of quality (in respect of quantity this is so with no animal, for
the young always increase in size after birth), and these generate living animals within themselves from the
first. The second class do not generate perfect animals within themselves from the first (for they are only
viviparous after first laying eggs), but still they are externally viviparous. The third class do not produce a
perfect animal, but an egg, and this egg is perfect. Those whose nature is still colder than these produce an
egg, but an imperfect one, which is perfected outside the body, as the class of scaly fishes, the Crustacea, and
the cephalopods. The fifth and coldest class does not even lay an egg from itself; but so far as the young ever
attain to this condition at all, it is outside the body of the parent, as has been said already. For insects produce
a scolex first; the scolex after developing becomes egg-like (for the so-called chrysalis or pupa is equivalent
to an egg); then from this it is that a perfect animal comes into being, reaching the end of its development in
the second change.

Some animals then, as said before, do not come into being from semen, but all the sanguinea do so which are
generated by copulation, the male emitting semen into the female when this has entered into her the young
are formed and assume their peculiar character, some within the animals themselves when they are
viviparous, others in eggs.

There is a considerable difficulty in understanding how the plant is formed out of the seed or any animal out
of the semen. Everything that comes into being or is made must (1) be made out of something, (2) be made
by the agency of something, and (3) must become something. Now that out of which it is made is the
material; this some animals have in its first form within themselves, taking it from the female parent, as all
those which are not born alive but produced as a scolex or an egg; others receive it from the mother for a long
time by sucking, as the young of all those which are not only externally but also internally viviparous. Such,
then, is the material out of which things come into being, but we now are inquiring not out of what the parts
of an animal are made, but by what agency. Either it is something external which makes them, or else
something existing in the seminal fluid and the semen; and this must either be soul or a part of soul, or
something containing soul.

Now it would appear irrational to suppose that any of either the internal organs or the other parts is made by
something external, since one thing cannot set up a motion in another without touching it, nor can a thing be
affected in any way by another if it does not set up a motion in it. Something then of the sort we require exists
in the embryo itself, being either a part of it or separate from it. To suppose that it should be something else
separate from it is irrational. For after the animal has been produced does this something perish or does it
remain in it? But nothing of the kind appears to be in it, nothing which is not a part of the whole plant or
animal. Yet, on the other hand, it is absurd to say that it perishes after making either all the parts or only some
of them. If it makes some of the parts and then perishes, what is to make the rest of them? Suppose this
something makes the heart and then perishes, and the heart makes another organ, by the same argument either
all the parts must perish or all must remain. Therefore it is preserved and does not perish. Therefore it is a

Book II 23

ON THE GENERATION OF ANIMALS

part of the embryo itself which exists in the semen from the beginning; and if indeed there is no part of the
soul which does not exist in some part of the body, it would also be a part containing soul in it from the
beginning.

How, then, does it make the other parts? Either all the parts, as heart, lung, liver, eye, and all the rest, come
into being together or in succession, as is said in the verse ascribed to Orpheus, for there he says that an
animal comes into being in the same way as the knitting of a net. That the former is not the fact is plain even
to the senses, for some of the parts are clearly visible as already existing in the embryo while others are not;
that it is not because of their being too small that they are not visible is clear, for the lung is of greater size
than the heart, and yet appears later than the heart in the original development. Since, then, one is earlier and
another later, does the one make the other, and does the later part exist on account of the part which is next to
it, or rather does the one come into being only after the other? I mean, for instance, that it is not the fact that
the heart, having come into being first, then makes the liver, and the liver again another organ, but that the
liver only comes into being after the heart, and not by the agency of the heart, as a man becomes a man after
being a boy, not by his agency. An explanation of this is that, in all the productions of Nature or of art, what
already exists potentially is brought into being only by what exists actually; therefore if one organ formed
another the form and the character of the later organ would have to exist in the earlier, e.g. the form of the
liver in the heart. And otherwise also the theory is strange and fictitious.

Yet again, if the whole animal or plant is formed from semen or seed, it is impossible that any part of it
should exist ready made in the semen or seed, whether that part be able to make the other parts or no. For it is
plain that, if it exists in it from the first, it was made by that which made the semen. But semen must be made
first, and that is the function of the generating parent. So, then, it is not possible that any part should exist in
it, and therefore it has not within itself that which makes the parts.

But neither can this agent be external, and yet it must needs be one or other of the two. We must try, then, to
solve this difficulty, for perhaps some one of the statements made cannot be made without qualification, e.g.
the statement that the parts cannot be made by what is external to the semen. For if in a certain sense they
cannot, yet in another sense they can. (Now it makes no difference whether we say 'the semen' or 'that from
which the semen comes', in so far as the semen has in itself the movement initiated by the other.) It is
possible, then, that A should move B, and B move C; that, in fact, the case should be the same as with the
automatic machines shown as curiosities. For the parts of such machines while at rest have a sort of
potentiality of motion in them, and when any external force puts the first of them in motion, immediately the
next is moved in actuality. As, then, in these automatic machines the external force moves the parts in a
certain sense (not by touching any part at the moment, but by having touched one previously), in like manner
also that from which the semen comes, or in other words that which made the semen, sets up the movement
in the embryo and makes the parts of it by having first touched something though not continuing to touch it.
In a way it is the innate motion that does this, as the act of building builds the house. Plainly, then, while
there is something which makes the parts, this does not exist as a definite object, nor does it exist in the
semen at the first as a complete part.

But how is each part formed? We must answer this by starting in the first instance from the principle that, in
all products of Nature or art, a thing is made by something actually existing out of that which is potentially
such as the finished product. Now the semen is of such a nature, and has in it such a principle of motion, that
when the motion is ceasing each of the parts comes into being, and that as a part having life or soul. For there
is no such thing as face or flesh without life or soul in it; it is only equivocally that they will be called face or
flesh if the life has gone out of them, just as if they had been made of stone or wood. And the homogeneous
parts and the organic come into being together. And just as we should not say that an axe or other instrument
or organ was made by the fire alone, so neither shall we say that foot or hand were made by heat alone. The
same applies also to flesh, for this too has a function. While, then, we may allow that hardness and softness,
stickiness and brittleness, and whatever other qualities are found in the parts that have life and soul, may be

Book II 24

ON THE GENERATION OF ANIMALS

caused by mere heat and cold, yet, when we come to the principle in virtue of which flesh is flesh and bone is
bone, that is no longer so; what makes them is the movement set up by the male parent, who is in actuality
what that out of which the offspring is made is in potentiality. This is what we find in the products of art; heat
and cold may make the iron soft and hard, but what makes a sword is the movement of the tools employed,
this movement containing the principle of the art. For the art is the starting-point and form of the product;
only it exists in something else, whereas the movement of Nature exists in the product itself, issuing from
another nature which has the form in actuality.

Has the semen soul, or not? The same argument applies here as in the question concerning the parts. As no
part, if it participate not in soul, will be a part except in an equivocal sense (as the eye of a dead man is still
called an 'eye'), so no soul will exist in anything except that of which it is soul; it is plain therefore that semen
both has soul, and is soul, potentially.

But a thing existing potentially may be nearer or further from its realization in actuality, as e.g. a
mathematician when asleep is further from his realization in actuality as engaged in mathematics than when
he is awake, and when awake again but not studying mathematics he is further removed than when he is so
studying. Accordingly it is not any part that is the cause of the soul's coming into being, but it is the first
moving cause from outside. (For nothing generates itself, though when it has come into being it
thenceforward increases itself.) Hence it is that only one part comes into being first and not all of them
together. But that must first come into being which has a principle of increase (for this nutritive power exists
in all alike, whether animals or plants, and this is the same as the power that enables an animal or plant to
generate another like itself, that being the function of them all if naturally perfect). And this is necessary for
the reason that whenever a living thing is produced it must grow. It is produced, then, by something else of
the same name, as e.g. man is produced by man, but it is increased by means of itself. There is, then,
something which increases it. If this is a single part, this must come into being first. Therefore if the heart is
first made in some animals, and what is analogous to the heart in the others which have no heart, it is from
this or its analogue that the first principle of movement would arise.

We have thus discussed the difficulties previously raised on the question what is the efficient cause of
generation in each case, as the first moving and formative power.

The next question to be mooted concerns the nature of semen. For whereas when it issues from the animal it
is thick and white, yet on cooling it becomes liquid as water, and its colour is that of water. This would
appear strange, for water is not thickened by heat; yet semen is thick when it issues from within the animal's
body which is hot, and becomes liquid on cooling. Again, watery fluids freeze, but semen, if exposed in frosts
to the open air, does not freeze but liquefies, as if it was thickened by the opposite of cold. Yet it is
unreasonable, again, to suppose that it is thickened by heat. For it is only substances having a predominance
of earth in their composition that coagulate and thicken on boiling, e.g. milk. It ought then to solidify on
cooling, but as a matter of fact it does not become solid in any part but the whole of it goes like water.

This then is the difficulty. If it is water, water evidently does not thicken through heat, whereas the semen is
thick and both it and the body whence it issues are hot. If it is made of earth or a mixture of earth and water, it
ought not to liquefy entirely and turn to water.

Perhaps, however, we have not discriminated all the possibilities. It is not only the liquids composed of water
and earthy matter that thicken, but also those composed of water and air; foam, for instance, becomes thicker
and white, and the smaller and less visible the bubbles in it, the whiter and firmer does the mass appear. The
same thing happens also with oil; on mixing with air it thickens, wherefore that which is whitening becomes

2 25

ON THE GENERATION OF ANIMALS

thicker, the watery part in it being separated off by the heat and turning to air. And if oxide of lead is mixed
with water or even with oil, the mass increases greatly and changes from liquid and dark to firm and white,
the reason being that air is mixed in with it which increases the mass and makes the white shine through, as in
foam and snow (for snow is foam). And water itself on mingling with oil becomes thick and white, because
air is entangled in it by the act of pounding them together, and oil itself has much air in it (for shininess is a
property of air, not of earth or water). This too is why it floats on the surface of the water, for the air
contained in it as in a vessel bears it up and makes it float, being the cause of its lightness. So too oil is
thickened without freezing in cold weather and frosts; it does not freeze because of its heat (for the air is hot
and will not freeze), but because the air is forced together and compressed, as..., by the cold, the oil becomes
thicker. These are the reasons why semen is firm and white when it issues from within the animal; it has a
quantity of hot air in it because of the internal heat; afterwards, when the heat has evaporated and the air has
cooled, it turns liquid and dark; for the water, and any small quantity of earthy matter there may be, remain in
semen as it dries, as they do in phlegm.

Semen, then, is a compound of spirit (pneuma) and water, and the former is hot air (aerh); hence semen is
liquid in its nature because it is made of water. What Ctesias the Cnidian has asserted of the semen of
elephants is manifestly untrue; he says that it hardens so much in drying that it becomes like amber. But this
does not happen, though it is true that one semen must be more earthy than another, and especially so with
animals that have much earthy matter in them because of the bulk of their bodies. And it is thick and white
because it is mixed with spirit, for it is also an invariable rule that it is white, and Herodotus does not report
the truth when he says that the semen of the Aethiopians is black, as if everything must needs be black in
those who have a black skin, and that too when he saw their teeth were white. The reason of the whiteness of
semen is that it is a foam, and foam is white, especially that which is composed of the smallest parts, small in
the sense that each bubble is invisible, which is what happens when water and oil are mixed and shaken
together, as said before. (Even the ancients seem to have noticed that semen is of the nature of foam; at least
it was from this they named the goddess who presides over union.)

This then is the explanation of the problem proposed, and it is plain too that this is why semen does not
freeze; for air will not freeze.

The next question to raise and to answer is this. If, in the case of those animals which emit semen into the
female, that which enters makes no part of the resulting embryo, where is the material part of it diverted if (as
we have seen) it acts by means of the power residing in it? It is not only necessary to decide whether what is
forming in the female receives anything material, or not, from that which has entered her, but also concerning
the soul in virtue of which an animal is so called (and this is in virtue of the sensitive part of the soul)- does
this exist originally in the semen and in the unfertilized embryo or not, and if it does whence does it come?
For nobody would put down the unfertilized embryo as soulless or in every sense bereft of life (since both the
semen and the embryo of an animal have every bit as much life as a plant), and it is productive up to a certain
point. That then they possess the nutritive soul is plain (and plain is it from the discussions elsewhere about
soul why this soul must be acquired first). As they develop they also acquire the sensitive soul in virtue of
which an animal is an animal. For e.g. an animal does not become at the same time an animal and a man or a
horse or any other particular animal. For the end is developed last, and the peculiar character of the species is
the end of the generation in each individual. Hence arises a question of the greatest difficulty, which we must
strive to solve to the best of our ability and as far as possible. When and how and whence is a share in reason
acquired by those animals that participate in this principle? It is plain that the semen and the unfertilized
embryo, while still separate from each other, must be assumed to have the nutritive soul potentially, but not
actually, except that (like those unfertilized embryos that are separated from the mother) it absorbs
nourishment and performs the function of the nutritive soul. For at first all such embryos seem to live the life

3 26

ON THE GENERATION OF ANIMALS

of a plant. And it is clear that we must be guided by this in speaking of the sensitive and the rational soul. For
all three kinds of soul, not only the nutritive, must be possessed potentially before they are possessed in
actuality. And it is necessary either (1) that they should all come into being in the embryo without existing
previously outside it, or (2) that they should all exist previously, or (3), that some should so exist and others
not. Again, it is necessary that they should either (1) come into being in the material supplied by the female
without entering with the semen of the male, or (2) come from the male and be imparted to the material in the
female. If the latter, then either all of them, or none, or some must come into being in the male from outside.

Now that it is impossible for them all to preexist is clear from this consideration. Plainly those principles
whose activity is bodily cannot exist without a body, e.g. walking cannot exist without feet. For the same
reason also they cannot enter from outside. For neither is it possible for them to enter by themselves, being
inseparable from a body, nor yet in a body, for the semen is only a secretion of the nutriment in process of
change. It remains, then, for the reason alone so to enter and alone to be divine, for no bodily activity has any
connexion with the activity of reason.

Now it is true that the faculty of all kinds of soul seems to have a connexion with a matter different from and
more divine than the so-called elements; but as one soul differs from another in honour and dishonour, so
differs also the nature of the corresponding matter. All have in their semen that which causes it to be
productive; I mean what is called vital heat. This is not fire nor any such force, but it is the spiritus included
in the semen and the foam-like, and the natural principle in the spiritus, being analogous to the element of
the stars. Hence, whereas fire generates no animal and we do not find any living thing forming in either solids
or liquids under the influence of fire, the heat of the sun and that of animals does generate them. Not only is
this true of the heat that works through the semen, but whatever other residuum of the animal nature there
may be, this also has still a vital principle in it. From such considerations it is clear that the heat in animals
neither is fire nor derives its origin from fire.

Let us return to the material of the semen, in and with which comes away from the male the spiritus
conveying the principle of soul. Of this principle there are two kinds; the one is not connected with matter,
and belongs to those animals in which is included something divine (to wit, what is called the reason), while
the other is inseparable from matter. This material of the semen dissolves and evaporates because it has a
liquid and watery nature. Therefore we ought not to expect it always to come out again from the female or to
form any part of the embryo that has taken shape from it; the case resembles that of the fig-juice which
curdles milk, for this too changes without becoming any part of the curdling masses.

It has been settled, then, in what sense the embryo and the semen have soul, and in what sense they have not;
they have it potentially but not actually.

Now semen is a secretion and is moved with the same movement as that in virtue of which the body increases
(this increase being due to subdivision of the nutriment in its last stage). When it has entered the uterus it puts
into form the corresponding secretion of the female and moves it with the same movement wherewith it is
moved itself. For the female's contribution also is a secretion, and has all the arts in it potentially though none
of them actually; it has in it potentially even those parts which differentiate the female from the male, for just
as the young of mutilated parents are sometimes born mutilated and sometimes not, so also the young born of
a female are sometimes female and sometimes male instead. For the female is, as it were, a mutilated male,
and the catamenia are semen, only not pure; for there is only one thing they have not in them, the principle of
soul. For this reason, whenever a wind-egg is produced by any animal, the egg so forming has in it the parts
of both sexes potentially, but has not the principle in question, so that it does not develop into a living
creature, for this is introduced by the semen of the male. When such a principle has ben imparted to the
secretion of the female it becomes an embryo.

ON THE GENERATION OF ANIMALS

Liquid but corporeal substances become surrounded by some kind of covering on heating, like the solid scum
which forms on boiled foods when cooling. All bodies are held together by the glutinous; this quality, as the
embryo develops and increases in size, is acquired by the sinewy substance, which holds together the parts of
animals, being actual sinew in some and its analogue in others. To the same class belong also skin,
blood-vessels, membranes, and the like, for these differ in being more or less glutinous and generally in
excess and deficiency.

In those animals whose nature is comparatively imperfect, when a perfect embryo (which, however, is not yet
a perfect animal) has been formed, it is cast out from the mother, for reasons previously stated. An embryo is
then complete when it is either male or female, in the case of those animals who possess this distinction, for
some (i.e. all those which are not themselves produced from a male or female parent nor from a union of the
two) produce an offspring which is neither male nor female. Of the generation of these we shall speak later.

The perfect animals, those internally viviparous, keep the developing embryo within themselves and in close
connexion until they give birth to a complete animal and bring it to light.

A third class is externally viviparous but first internally oviparous; they develop the egg into a perfect
condition, and then in some cases the egg is set free as with creatures externally oviparous, and the animal is
produced from the egg within the mother's body; in other cases, when the nutriment from the egg is
consumed, development is completed by connection with the uterus, and therefore the egg is not set free from
the uterus. This character marks the cartilaginous fish, of which we must speak later by themselves.

Here we must make our first start from the first class; these are the perfect or viviparous animals, and of these
the first is man. Now the secretion of the semen takes place in all of them just as does that of any other
residual matter. For each is conveyed to its proper place without any force from the breath or compulsion of
any other cause, as some assert, saying that the generative parts attract the semen like cupping-glasses, aided
by the force of the breath, as if it were possible for either this secretion or the residue of the solid and liquid
nutriment to go anywhere else than they do without the exertion of such a force. Their reason is that the
discharge of both is attended by holding the breath, but this is a common feature of all cases when it is
necessary to move anything, because strength arises through holding the breath. Why, even without this force
the secretions or excretions are discharged in sleep if the parts concerned are full of them and are relaxed.
One might as well say that it is by the breath that the seeds of plants are always segregated to the places
where they are wont to bear fruit. No, the real cause, as has been stated already, is that there are special parts
for receiving all the secretions, alike the useless (as the residues of the liquid and solid nutriment), and the
blood, which has the so-called blood-vessels.

To consider now the region of the uterus in the female- the two blood-vessels, the great vessel and the aorta,
divide higher up, and many fine vessels from them terminate in the uterus. These become over-filled from
the nourishment they convey, nor is the female nature able to concoct it, because it is colder than man's; so
the blood is excreted through very fine vessels into the uterus, these being unable on account of their
narrowness to receive the excessive quantity, and the result is a sort of haemorrhage. The period is not
accurately defined in women, but tends to return during the waning of the moon. This we should expect, for
the bodies of animals are colder when the environment happens to become so, and the time of change from
one month to another is cold because of the absence of the moon, whence also it results that this time is
stormier than the middle of the month. When then the residue of the nourishment has changed into blood, the
catamenia tend to occur at the above-mentioned period, but when it is not concocted a little matter at a time
is always coming away, and this is why 'whites' appear in females while still small, in fact mere children. If
both these discharges of the secretions are moderate, the body remains in good health, for they act as a

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ON THE GENERATION OF ANIMALS

purification of the secretions which are the causes of a morbid state of body; if they do not occur at all or if
they are excessive, they are injurious, either causing illness or pulling down the patient; hence whites, if
continuous and excessive, prevent girls from growing. This secretion then is necessarily discharged by
females for the reasons given; for, the female nature being unable to concoct the nourishment thoroughly,
there must not only be left a residue of the useless nutriment, but also there must be a residue in the
blood-vessels, and this filling the channels of the finest vessels must overflow. Then Nature, aiming at the
best end, uses it up in this place for the sake of generation, that another creature may come into being of the
same kind as the former was going to be, for the menstrual blood is already potentially such as the body from
which it is discharged.

In all females, then, there must necessarily be such a secretion, more indeed in those that have blood and of
these most of all in man, but in the others also some matter must be collected in the uterine region. The
reason why there is more in those that have blood and most in man has been already given, but why, if all
females have such a secretion, have not all males one to correspond? For some of them do not emit semen
but, just as those which do emit it fashion by the movement in the semen the mass forming from the material
supplied by the female, so do the animals in question bring the same to pass and exert the same formative
power by the movement within themselves in that part from whence the semen is secreted. This is the region
about the diaphragm in all those animals which have one, for the heart or its analogue is the first principle of
a natural body, while the lower part is a mere addition for the sake of it. Now the reason why it is not all
males that have a generative secretion, while all females do, is that the animal is a body with Soul or life; the
female always provides the material, the male that which fashions it, for this is the power that we say they
each possess, and this is what is meant by calling them male and female. Thus while it is necessary for the
female to provide a body and a material mass, it is not necessary for the male, because it is not within the
work of art or the embryo that the tools or the maker must exist. While the body is from the female, it is the
soul that is from the male, for the soul is the reality of a particular body. For this reason if animals of a
different kind are crossed (and this is possible when the periods of gestation are equal and conception takes
place nearly at the same season and there is no great difference in the of the animals), the first cross has a
common resemblance to both parents, as the hybrid between fox and dog, partridge and domestic fowl, but as
time goes on and one generation springs from another, the final result resembles the female in form, just as
foreign seeds produce plants varying in accordance with the country in which they are sown. For it is the soil
that gives to the seeds the material and the body of the plant. And hence the part of the female which receives
the semen is not a mere passage, but the uterus has a considerable width, whereas the males that emit semen
have only passages for this purpose, and these are bloodless.

Each of the secretions becomes such at the moment when it is in its proper place; before that there is nothing
of the sort unless with much violence and contrary to nature.

We have thus stated the reason for which the generative secretions are formed in animals. But when the
semen from the male (in those animals which emit semen) has entered, it puts into form the purest part of the
female secretion (for the greater part of the catamenia also is useless and fluid, as is the most fluid part of the
male secretion, i.e. in a single emission, the earlier discharge being in most cases apt to be infertile rather than
the later, having less vital heat through want of concoction, whereas that which is concocted is thick and of a
more material nature).

If there is no external discharge, either in women or other animals, on account of there not being much
useless and superfluous matter in the secretion, then the quantity forming within the female altogether is as
much as what is retained within those animals which have an external discharge; this is put into form by the
power of the male residing in the semen secreted by him, or, as is clearly seen to happen in some insects, by
the part in the female analogous to the uterus being inserted into the male.

ON THE GENERATION OF ANIMALS

It has been previously stated that the discharge accompanying sexual pleasure in the female contributes
nothing to the embryo. The chief argument for the opposite view is that what are called bad dreams occur by
night with women as with men; but this is no proof, for the same thing happens to young men also who do
not yet emit semen, and to those who do emit semen but whose semen is infertile.

It is impossible to conceive without the emission of the male in union and without the secretion of the
corresponding female material, whether it be discharged externally or whether there is only enough within the
body. Women conceive, however, without experiencing the pleasure usual in such intercourse, if the part
chance to be in heat and the uterus to have descended. But generally speaking the opposite is the case,
because the os uteri is not closed when the discharge takes place which is usually accompanied by pleasure in
women as well as men, and when this is so there is a readier way for the semen of the male to be drawn into
the uterus.

The actual discharge does not take place within the uterus as some think, the os uteri being too narrow, but it
is in the region in front of this, where the female discharges the moisture found in some cases, that the male
emits the semen. Sometimes it remains in this place; at other times, if the uterus chance to be conveniently
placed and hot on account of the purgation of the catamenia, it draws it within itself. A proof of this is that
pessaries, though wet when applied, are removed dry. Moreover, in all those animals which have the uterus
near the hypozoma, as birds and viviparous fishes, it is impossible that the semen should be so discharged as
to enter it; it must be drawn into it. This region, on account of the heat which is in it, attracts the semen. The
discharge and collection of the catamenia also excite heat in this part. Hence it acts like cone-shaped vessels
which, when they have been washed out with hot water, their mouth being turned downwards, draw water
into themselves. And this is the way things are drawn up, but some say that nothing of the kind happens with
the organic parts concerned in copulation. Precisely the opposite is the case of those who say the woman
emits semen as well as the man, for if she emits it outside the uterus this must then draw it back again into
itself if it is to be mixed with the semen of the male. But this is a superfluous proceeding, and Nature does
nothing superfluous.

When the material secreted by the female in the uterus has been fixed by the semen of the male (this acts in
the same way as rennet acts upon milk, for rennet is a kind of milk containing vital heat, which brings into
one mass and fixes the similar material, and the relation of the semen to the catamenia is the same, milk and
the catamenia being of the same nature)- when, I say, the more solid part comes together, the liquid is
separated off from it, and as the earthy parts solidify membranes form all round it; this is both a necessary
result and for a final cause, the former because the surface of a mass must solidify on heating as well as on
cooling, the latter because the foetus must not be in a liquid but be separated from it. Some of these are called
membranes and others choria, the difference being one of more or less, and they exist in ovipara and vivipara
alike.

When the embryo is once formed, it acts like the seeds of plants. For seeds also contain the first principle of
growth in themselves, and when this (which previously exists in them only potentially) has been
differentiated, the shoot and the root are sent off from it, and it is by the root that the plant gets nourishment;
for it needs growth. So also in the embryo all the parts exist potentially in a way at the same time, but the first
principle is furthest on the road to realization. Therefore the heart is first differentiated in actuality. This is
clear not only to the senses (for it is so) but also on theoretical grounds. For whenever the young animal has
been separated from both parents it must be able to manage itself, like a son who has set up house away from
his father. Hence it must have a first principle from which comes the ordering of the body at a later stage also,
for if it is to come in from outside at later period to dwell in it, not only may the question be asked at what
time it is to do so, but also we may object that, when each of the parts is separating from the rest, it is
necessary that this principle should exist first from which comes growth and movement to the other parts.
(Wherefore all who say, as did Democritus, that the external parts of animals are first differentiated and the
internal later, are much mistaken; it is as if they were talking of animals of stone or wood. For such as these

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ON THE GENERATION OF ANIMALS

have no principle of growth at all, but all animals have, and have it within themselves.) Therefore it is that the
heart appears first distinctly marked off in all the sanguinea, for this is the first principle or origin of both
homogeneous and heterogeneous parts, since from the moment that the animal or organism needs
nourishment, from that moment does this deserve to be called its principle or origin. For the animal grows,
and the nutriment, in its final stage, of an animal is the blood or its analogue, and of this the blood-vessels
are the receptacle, wherefore the heart is the principle or origin of these also. (This is clear from the Enquiries
and the anatomical drawings.)

Since the embryo is already potentially an animal but an imperfect one, it must obtain its nourishment from
elsewhere; accordingly it makes use of the uterus and the mother, as a plant does of the earth, to get
nourishment, until it is perfected to the point of being now an animal potentially locomotive. So Nature has
first designed the two blood-vessels from the heart, and from these smaller vessels branch off to the uterus.
These are what is called the umbilicus, for this is a blood-vessel, consisting of one or more vessels in
different animals. Round these is a skin-like integument, because the weakness of the vessels needs
protection and shelter. The vessels join on to the uterus like the roots of plants, and through them the embryo
receives its nourishment. This is why the animal remains in the uterus, not, as Democritus says, that the parts
of the embryo may be moulded in conformity with those of the mother. This is plain in the ovipara, for they
have their parts differentiated in the egg after separation from the matrix.

Here a difficulty may be raised. If the blood is the nourishment, and if the heart, which first comes into being,
already contains blood, and the nourishment comes from outside, whence did the first nourishment enter?
Perhaps it is not true that all of it comes from outside just as in the seeds of plants there is something of this
nature, the substance which at first appears milky, so also in the material of the animal embryo the
superfluous matter of which it is formed is its nourishment from the first.

The embryo, then, grows by means of the umbilicus in the same way as a plant by its roots, or as animals
themselves when separated from the nutriment within the mother, of which we must speak later at the time
appropriate for discussing them. But the parts are not differentiated, as some suppose, because like is
naturally carried to like. Besides many other difficulties involved in this theory, it results from it that the
homogeneous parts ought to come into being each one separate from the rest, as bones and sinews by
themselves, and flesh by itself, if one should accept this cause. The real cause why each of them comes into
being is that the secretion of the female is potentially such as the animal is naturally, and all the parts are
potentially present in it, but none actually. It is also because when the active and the passive come in contact
with each other in that way in which the one is active and the other passive (I mean in the right manner, in the
right place, and at the right time), straightway the one acts and the other is acted upon. The female, then,
provides matter, the male the principle of motion. And as the products of art are made by means of the tools
of the artist, or to put it more truly by means of their movement, and this is the activity of the art, and the art
is the form of what is made in something else, so is it with the power of the nutritive soul. As later on in the
case of mature animals and plants this soul causes growth from the nutriment, using heat and cold as its tools
(for in these is the movement of the soul), and each thing comes into being in accordance with a certain
formula, so also from the beginning does it form the product of nature. For the material by which this latter
grows is the same as that from which it is constituted at first; consequently also the power which acts upon it
is identical with that which originally generated it; if then this acting power is the nutritive soul, this is also
the generative soul, and this is the nature of every organism, existing in all animals and plants. [But the other
parts of the soul exist in some animals, not in others.] In plants, then, the female is not separated from the
male, but in those animals in which it is separated the male needs the female besides.

And yet the question may be raised why it is that, if indeed the female possesses the same soul and if it is the
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ON THE GENERATION OF ANIMALS

secretion of the female which is the material of the embryo, she needs the male besides instead of generating
entirely from herself. The reason is that the animal differs from the plant by having sense-perception; if the
sensitive soul is not present, either actually or potentially, and either with or without qualification, it is
impossible for face, hand, flesh, or any other part to exist; it will be no better than a corpse or part of a corpse.
If then, when the sexes are separated, it is the male that has the power of making the sensitive soul, it is
impossible for the female to generate an animal from itself alone, for the process in question was seen to
involve the male quality. Certainly that there is a good deal in the difficulty stated is plain in the case of the
birds that lay wind-eggs, showing that the female can generate up to a certain point unaided. But this still
involves a difficulty; in what way are we to say that their eggs live? It neither possible that they should live in
the same way as fertile eggs (for then they would produce a chick actually alive), nor yet can they be called
eggs only in the sense in which an egg of wood or stone is so called, for the fact that these eggs go bad shows
that they previously participate in some way in life. It is plain, then, that they have some soul potentially.
What sort of soul will this be? It must be the lowest surely, and this is the nutritive, for this exists in all
animals and plants alike. Why then does it not perfect the parts and the animal? Because they must have a
sensitive soul, for the parts of animals are not like those of a plant. And so the female animal needs the help
of the male, for in these animals we are speaking of the male is separate. This is exactly what we find, for the
wind-eggs become fertile if the male tread the female in a certain space of time. About the cause of these
things, however, we shall enter into detail later.

If there is any kind of animal which is female and has no male separate from it, it is possible that this may
generate a young one from itself without copulation. No instance of this worthy of credit has been observed
up to the present at any rate, but one case in the class of fishes makes us hesitate. No male of the so-called
erythrinus has ever yet been seen, but females, and specimens full of roe, have been seen. Of this, however,
we have as yet no proof worthy of credit. Again, some members of the class of fishes are neither male nor
female, as eels and a kind of mullets found in stagnant waters. But whenever the sexes are separate the female
cannot generate perfectly by herself alone, for then the male would exist in vain, and Nature makes nothing in
vain. Hence in such animals the male always perfects the work of generation, for he imparts the sensitive
soul, either by means of the semen or without it. Now the parts of the embryo already exist potentially in the
material, and so when once the principle of movement has been imparted to them they develop in a chain one
after another, as the wheels are moved one by another in the automatic machines. When some of the natural
philosophers say that like is brought to like, this must be understood, not in the sense that the parts are moved
as changing place, but that they stay where they are and the movement is a change of quality (such as
softness, hardness, colour, and the other differences of the homogeneous parts); thus they become in actuality
what they previously were in potentiality. And what comes into being first is the first principle; this is the
heart in the sanguinea and its analogue in the rest, as has been often said already. This is plain not only to the
senses (that it is first to come into being), but also in view of its end; for life fails in the heart last of all, and it
happens in all cases that what comes into being last fails first, and the first last, Nature running a double
course, so to say, and turning back to the point from whence she started. For the process of becoming is from
the non-existent to the existent, and that of perishing is back again from the existent to the non-existent.

After this, as said already, the internal parts come into being before the external. The greater become visible
before the less, even if some of them do not come into being before them. First the parts above the hypozoma
are differentiated and are superior in size; the part below is both smaller and less differentiated. This happens
in all animals in which exists the distinction of upper and lower, except in the insects; the growth of those
that produce a scolex is towards the upper part, for this is smaller in the beginning. The cephalopoda are the
only locomotive animals in which the distinction of upper and lower does not exist.

What has been said applies to plants also, that the upper portion is earlier in development than the lower, for
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ON THE GENERATION OF ANIMALS

the roots push out from the seed before the shoots.

The agency by which the parts of animals are differentiated is air, not however that of the mother nor yet of
the embryo itself, as some of the physicists say. This is manifest in birds, fishes, and insects. For some of
these are separated from the mother and produced from an egg, within which the differentiation takes place;
other animals do not breathe at all, but are produced as a scolex or an egg; those which do breathe and whose
parts are differentiated within the mother's uterus yet do not breathe until the lung is perfected, and the lung
and the preceding parts are differentiated before they breathe. Moreover, all polydactylous quadrupeds, as
dog, lion, wolf, fox, jackal, produce their young blind, and the eyelids do not separate till after birth.
Manifestly the same holds also in all the other parts; as the qualitative, so also the quantitative differentia
comes into being, pre-existing potentially but being actualized later by the same causes by which the
qualitative distinction is produced, and so the eyelids become two instead of one. Of course air must be
present, because heat and moisture are present, the former acting and the latter being acted upon.

Some of the ancient nature-philosolphers made an attempt to state which part comes into being after which,
but were not sufficiently acquainted with the facts. It is with the parts as with other things; one naturally
exists prior to another. But the word 'prior' is used in more senses than one. For there is a difference between
the end or final cause and that which exists for the sake of it; the latter is prior in order of development, the
former is prior in reality. Again, that which exists for the sake of the end admits of division into two classes,
(1) the origin of the movement, (2) that which is used by the end; I mean, for instance, (1) that which can
generate, (2) that which serves as an instrument to what is generated, for the one of these, that which makes,
must exist first, as the teacher before the learner, and the other later, as the pipes are later than he who learns
to play upon them, for it is superfluous that men who do not know how to play should have pipes. Thus there
are three things: first, the end, by which we mean that for the sake of which something else exists; secondly,
the principle of movement and of generation, existing for the sake of the end (for that which can make and
generate, considered simply as such, exists only in relation to what is made and generated); thirdly, the
useful, that is to say what the end uses. Accordingly, there must first exist some part in which is the principle
of movement (I say a part because this is from the first one part of the end and the most important part too);
next after this the whole and the end; thirdly and lastly, the organic parts serving these for certain uses. Hence
if there is anything of this sort which must exist in animals, containing the principle and end of all their
nature, this must be the first to come into being- first, that is, considered as the moving power, but
simultaneous with the whole embryo if considered as a part of the end. Therefore all the organic parts whose
nature is to bring others into being must always themselves exist before them, for they are for the sake of
something else, as the beginning for the sake of the end; all those parts which are for the sake of something
else but are not of the nature of beginnings must come into being later. So it is not easy to distinguish which
of the parts are prior, those which are for the sake of another or that for the sake of which are the former. For
the parts which cause the movement, being prior to the end in order of development, come in to cause
confusion, and it is not easy to distinguish these as compared with the organic parts. And yet it is in
accordance with this method that we must inquire what comes into being after what; for the end is later than
some parts and earlier than others. And for this reason that part which contains the first principle comes into
being first, next to this the upper half of the body. This is why the parts about the head, and particularly the
eyes, appear largest in the embryo at an early stage, while the parts below the umbilicus, as the legs, are
small; for the lower parts are for the sake of the upper, and are neither parts of the end nor able to form it.

But they do not say well nor do they assign a necessary cause who say simply that 'it always happens so', and
imagine that this is a first principle in these cases. Thus Democritus of Abdera says that 'there is no beginning
of the infinite; now the cause is a beginning, and the eternal is infinite; in consequence, to ask the cause of
anything of this kind is to seek for a beginning of the infinite'. Yet according to this argument, which forbids
us to seek the cause, there will be no proof of any eternal truth whatever; but we see that there is a proof of
many such, whether by 'eternal' we mean what always happens or what exists eternally; it is an eternal truth
that the angles of a triangle are always equal to two right angles, or that the diagonal of a square is

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ON THE GENERATION OF ANIMALS

incommensurable with the side, and nevertheless a cause and a proof can be given for these truths. While,
then, it is well said that we must not take on us to seek a beginning (or first principle) of all things, yet this is
not well said of all things whatever that always are or always happen, but only of those which really are first
principles of the eternal things; for it is by another method, not by proof, that we acquire knowledge of the
first principle. Now in that which is immovable and unchanging the first principle is simply the essence of the
thing, but when we come to those things which come into being the principles are more than one, varying in
kind and not all of the same kind; one of this number is the principle of movement, and therefore in all the
sanguinea the heart is formed first, as was said at the beginning, and in the other animals that which is
analogous to the heart.

From the heart the blood-vessels extend throughout the body as in the anatomical diagrams which are
represented on the wall, for the parts lie round these because they are formed out of them. The homogeneous
parts are formed by heat and cold, for some are put together and solidified by the one and some by the other.
The difference between these has already been discussed elsewhere, and it has been stated what kinds of
things are soluble by liquid and fire, and what are not soluble by liquid and cannot be melted by fire. The
nutriment then oozes through the blood-vessels and the passages in each of the parts, like water in unbaked
pottery, and thus is formed the flesh or its analogues, being solidified by cold, which is why it is also
dissolved by fire. But all the particles given off which are too earthy, having but little moisture and heat, cool
as the moisture evaporates along with the heat; so they become hard and earthy in character, as nails, horns,
hoofs, and beaks, and therefore they are softened by fire but none of them is melted by it, while some of
them, as egg-shells, are soluble in liquids. The sinews and bones are formed by the internal heat as the
moisture dries, and hence the bones are insoluble by fire like pottery, for like it they have been as it were
baked in an oven by the heat in the process of development. But it is not anything whatever that is made into
flesh or bone by the heat, but only something naturally fitted for the purpose; nor is it made in any place or
time whatever, but only in a place and time naturally so fitted. For neither will that which exists potentially
be made except by that moving agent which possesses the actuality, nor will that which possesses the
actuality make anything whatever; the carpenter would not make a box except out of wood, nor will a box be
made out of the wood without the carpenter. The heat exists in the seminal secretion, and the movement and
activity in it is sufficient in kind and in quantity to correspond to each of the parts. In so far as there is any
deficiency or excess, the resulting product is in worse condition or physically defective, in like manner as in
the case of external substances which are thickened by boiling that they may be more palatable or for any
other purpose. But in the latter case it is we who apply the heat in due measure for the motion required; in the
former it is the nature of the male parent that gives it, or with animals spontaneously generated it is the
movement and heat imparted by the right season of the year that it is the cause.

Cooling, again, is mere deprivation of heat. Nature makes use of both; they have of necessity the power of
bringing about different results, but in the development of the embryo we find that the one cools and the other
heats for some definite purpose, and so each of the parts is formed; thus it is in one sense by necessity, in
another for a final cause, that they make the flesh soft, the sinews solid and elastic, the bones solid and brittle.
The skin, again, is formed by the drying of the flesh, like the scum upon boiled substances; it is so formed not
only because it is on the outside, but also because what is glutinous, being unable to evaporate, remains on
the surface. While in other animals the glutinous is dry, for which reason the covering of the invertebrates is
testaceous or crustaceous, in the vertebrates it is rather of the nature of fat. In all of these which are not of too
earthy a nature the fat is collected under the covering of the skin, a fact which points to the skin being formed
out of such a glutinous substance, for fat is somewhat glutinous. As we said, all these things must be
understood to be formed in one sense of necessity, but in another sense not of necessity but for a final cause.

The upper half of the body, then, is first marked out in the order of development; as time goes on the lower
also reaches its full size in the sanguinea. All the parts are first marked out in their outlines and acquire later
on their colour and softness or hardness, exactly as if Nature were a painter producing a work of art, for
painters, too, first sketch in the animal with lines and only after that put in the colours.

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ON THE GENERATION OF ANIMALS

Because the source of the sensations is in the heart, therefore this is the part first formed in the whole animal,
and because of the heat of this organ the cold forms the brain, where the blood-vessels terminate above,
corresponding to the heat of the heart. Hence the parts about the head begin to form next in order after the
heart, and surpass the other parts in size, for the brain is from the first large and fluid.

There is a difficulty about what happens with the eyes of animals. Though from the beginning they appear
very large in all creatures, whether they walk or swim or fly, yet they are the last of the parts to be formed
completely, for in the intervening time they collapse. The reason is this. The sense-organ of the eyes is set
upon certain passages, as are the other sense-organs. Whereas those of touch and taste are simply the body
itself or some part of the body of animals, those of smell and hearing are passages connecting with the
external air and full themselves of innate spiritus; these passages end at the small blood-vessels about the
brain which run thither from the heart. But the eye is the only sense-organ that has a bodily constitution
peculiar to itself. It is fluid and cold, and does not exist from the first in the place which it occupies later in
the same way as the other parts do, for they exist potentially to begin with and actually come into being later,
but the eye is the purest part of the liquidity about the brain drained off through the passages which are
visible running from them to the membrane round the brain. A proof of this is that, apart from the brain, there
is no other part in the head that is cold and fluid except the eye. Of necessity therefore this region is large at
first but falls in later. For the same thing happens with the brain; at first it is liquid and large, but in course of
evaporation and concoction it becomes more solid and falls in; this applies both to the brain and the eyes. The
head is very large at first, on account of the brain, and the eyes appear large because of the liquid in them.
They are the last organs to reach completion because the brain is formed with difficulty; for it is at a late
period that it gets rid of its coldness and fluidity; this applies to all animals possessing a brain, but especially
to man. For this reason the 'bregma' is the last of the bones to be formed; even after birth this bone is still soft
in children. The cause of this being so with men more than with other animals is the fact that their brain is the
most fluid and largest. This again is because the heat in man's heart is purest. His intellect shows how well he
is tempered, for man is the wisest of animals. And children for a long time have no control over their heads
on account of the heaviness of the brain; and the same applies to the parts which it is necessary to move, for it
is late that the principle of motion gets control over the upper parts, and last of all over those whose motion is
not connected directly with it, as that of the legs is not. Now the eyelid is such a part. But since Nature makes
nothing superfluous nor in vain, it is clear also that she makes nothing too late or too soon, for if she did the
result would be either in vain or superfluous. Hence it is necessary that the eyelids should be separated at the
same time as the heart is able to move them. So then the eyes of animals are perfected late because of the
amount of concoction required by the brain, and last of all the parts because the motion must be very strong
before it can affect parts so far from the first principle of motion and so cold. And it is plain that such is the
nature of the eyelids, for if the head is affected by never so little heaviness through sleepiness or drunkenness
or anything else of the kind, we cannot raise the eyelids though their own weight is so small. So much for the
question how the eyes come into being, and why and for what cause they are the last to be fully developed.

Each of the other parts is formed out of the nutriment, those most honourable and participating in the
sovereign principle from the nutriment which is first and purest and fully concocted, those which are only
necessary for the sake of the former parts from the inferior nutriment and the residues left over from the
other. For Nature, like a good householder, is not in the habit of throwing away anything from which it is
possible to make anything useful. Now in a household the best part of the food that comes in is set apart for
the free men, the inferior and the residue of the best for the slaves, and the worst is given to the animals that
live with them. Just as the intellect acts thus in the outside world with a view to the growth of the persons
concerned, so in the case of the embryo itself does Nature form from the purest material the flesh and the
body of the other sense-organs, and from the residues thereof bones, sinews, hair, and also nails and hoofs
and the like; hence these are last to assume their form, for they have to wait till the time when Nature has
some residue to spare.

ON THE GENERATION OF ANIMALS

The bones, then, are made in the first conformation of the parts from the seminal secretion or residue. As the
animal grows the bones grow from the natural nourishment, being the same as that of the sovereign parts, but
of this they only take up the superfluous residues. For everywhere the nutriment may be divided into two
kinds, the first and the second; the former is 'nutritious', being that which gives its essence both to the whole
and to the parts; the latter is concerned with growth, being that which causes quantitative increase. But these
must be distinguished more fully later on. The sinews are formed in the same way as the bones and out of the
same materials, the Seminal and nutritious residue. Nails, hair, hoofs, horns, beaks, the spurs of cocks, and
any other similar parts, are on the contrary formed from the nutriment which is taken later and only
concerned with growth, in other words that which is derived from the mother, or from the outer world after
birth. For this reason the bones on the one hand only grow up to a certain point (for there is a limit of size in
all animals, and therefore also of the growth of the bones; if these had been always able to grow, all animals
that have bone or its analogue would grow as long as they lived, for these set the limit of size to animals.
What is the reason of their not always increasing in size must be stated later.) Hair, on the contrary, and
growths akin to hair go on growing as long as they exist at all, and increase yet more in diseases and when the
body is getting old and wasting, because more residual matter is left over, as owing to old age and disease
less is expended on the important parts, though when the residual matter also fails through age the hair fails
with it. But the contrary is the case with the bones, for they waste away along with the body and the other
parts. Hair actually goes on growing after death; it does not, however, begin growing then.

About the teeth a difficulty may be raised. They have actually the same nature as the bones, and are formed
out of the bones, but nails, hair, horns, and the like are formed out of the skin, and that is why they change in
colour along with it, for they become white, black, and all sorts of colours according to that of the skin. But
the teeth do nothing of the sort, for they are made out of the bones in all animals that have both bones and
teeth. Of all the bones they alone go on growing through life, as is plain with the teeth which grow out of the
straight line so as no longer to touch each other. The reason for their growth, as a final cause, is their
function, for they would soon be worn down if there were not some means of saving them; even as it is they
are altogether worn down in old age in some animals which eat much and have not large teeth, their growth
not being in proportion to their detrition. And so Nature has contrived well to meet the case in this also, for
she causes the failure of the teeth to synchronize with old age and death. If life lasted for a thousand or ten
thousand years the original teeth must have been very large indeed, and many sets of them must have been
produced, for even if they had grown continuously they would still have been worn smooth and become
useless for their work. The final cause of their growth has been now stated, but besides this as a matter of fact
the growth of the teeth is not the same as that of the other bones. The latter all come into being in the first
formation of the embryo and none of them later, but the teeth do so later. Therefore it is possible for them to
grow again after the first set falls out, for though they touch the bones they are not connate with them. They
are formed, however, out of the nutriment distributed to the bones, and so have the same nature, even when
the bones have their own number complete.

Other animals are born in possession of teeth or their analogue (unless in cases contrary to Nature), because
when they are set free from the parent they are more perfect than man; but man (also unless in cases contrary
to Nature) is born without them.

The reason will be stated later why some teeth are formed and fall out but others do not fall out.

It is because such parts are formed from a residue that man is the most naked in body of all animals and has
the smallest nails in proportion to his size; he has the least amount of earthy residue, but that part of the blood
which is not concocted is the residue, and the earthy part in the bodies of all animals is the least concocted.
We have now stated how each of the parts is formed and what is the cause of their generation.

ON THE GENERATION OF ANIMALS

In viviparous animals, as said before, the embryo gets its growth through the umbilical cord. For since the
nutritive power of the soul, as well as the others, is present in animals, it straightway sends off this cord like a
root to the uterus. The cord consists of blood-vessels in a sheath, more numerous in the larger animals as
cattle and the like, one in the smallest, two in those of intermediate size. Through this cord the embryo
receives its nourishment in the form of blood, for the uterus is the termination of many blood-vessels. All
animals with no front teeth in the upper jaw, and all those which have them in both jaws and whose uterus
has not one great blood-vessel running through it but many close together instead- all these have in the
uterus the so-called cotyledons (with which the umbilical cord connects and is closely united; for the vessels
which pass through the cord run backwards and forwards between embryo and uterus and split up into
smaller vessels all over the uterus; where they terminate, there are found the cotyledons). Their convexity is
turned towards the uterus, the concavity towards the embryo. Between uterus and embryo are the chorion and
the membranes. As the embryo grows and approaches perfection the cotyledons become smaller and finally
disappear when it is perfected. For Nature sends the sanguineous nutriment for the embryo into this part of
the uterus as she sends milk into the breasts, and because the cotyledons are gradually aggregated from many
into a few the body of the cotyledon becomes like an eruption or inflammation. So long as the embryo is
comparatively small, being unable to receive much nutriment, they are plain and large, but when it has
increased in size they fall in together.

But most of the animals which have front teeth in both jaws and no horns have no cotyledons in the uterus,
but the umbilical cord runs to meet one blood-vessel, which is large and extends throughout the uterus. Of
such animals some produce one young at a time, some more than one, but the same description applies to
both these classes. (This should be studied with the aid of the examples drawn in the Anatomy and the
Enquiries.) For the young, if numerous, are attached each to its umbilical cord, and this to the blood-vessel of
the mother; they are arranged next to one another along the stream of the blood-vessel as along a canal; and
each embryo is enclosed in its membranes and chorion.

Those who say that children are nourished in the uterus by sucking some lump of flesh or other are mistaken.
If so, the same would have been the case with other animals, but as it is we do not find this (and this can
easily be observed by dissection). Secondly, all embryos alike, whether of creatures that fly or swim or walk,
are surrounded by fine membranes separating them from the uterus and from the fluids which are formed in
it; but neither in these themselves is there anything of the kind, nor is it possible for the embryo to take
nourishment by means of any of them. Thirdly, it is plain that all creatures developed in eggs grow when
separated from the uterus.

Natural intercourse takes place between animals of the same kind. However, those also unite whose nature is
near akin and whose form is not very different, if their size is much the same and if the periods of gestation
are equal. In other animals such cases are rare, but they occur with dogs and foxes and wolves; the Indian
dogs also spring from the union of a dog with some wild dog-like animal. A similar thing has been seen to
take place in those birds that are amative, as partridges and hens. Among birds of prey hawks of different
form are thought to unite, and the same applies to some other birds. Nothing worth mentioning has been
observed in the inhabitants of the sea, but the so-called 'rhinobates' especially is thought to spring from the
union of the 'rhini' and 'batus'. And the proverb about Libya, that 'Libya is always producing something new',
is said to have originated from animals of different species uniting with one another in that country, for it is
said that because of the want of water all meet at the few places where springs are to be found, and that even
different kinds unite in consequence.

Of the animals that arise from such union all except mules are found to copulate again with each other and to
be able to produce young of both sexes, but mules alone are sterile, for they do not generate by union with

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ON THE GENERATION OF ANIMALS

one another or with other animals. The problem why any individual, whether male or female, is sterile is a
general one, for some men and women are sterile, and so are other animals in their several kinds, as horses
and sheep. But this kind, of mules, is universally so. The causes of sterility in other animals are several. Both
men and women are sterile from birth when the parts useful for union are imperfect, so that men never grow a
beard but remain like eunuchs, and women do not attain puberty; the same thing may befall others as their
years advance, sometimes on account of the body being too well nourished (for men who are in too good
condition and women who are too fat the seminal secretion is taken up into the body, and the former have no
semen, the latter no catamenia); at other times by reason of sickness men emit the semen in a cold and liquid
state, and the discharges of women are bad and full of morbid secretions. Often, too, in both sexes this state is
caused by injuries in the parts and regions contributory to copulation. Some such cases are curable, others
incurable, but the subjects especially remain sterile if anything of the sort has happened in the first formation
of the parts in the embryo, for then are produced women of a masculine and men of a feminine appearance,
and in the former the catamenia do not occur, in the latter the semen is thin and cold. Hence it is with good
reason that the semen of men is tested in water to find out if it is infertile, for that which is thin and cold is
quickly spread out on the surface, but the fertile sinks to the bottom, for that which is well concocted is hot
indeed, but that which is firm and thick is well concocted. They test women by pessaries to see if the smells
thereof permeate from below upwards to the breath from the mouth and by colours smeared upon the eyes to
see if they colour the saliva. If these results do not follow it is a sign that the passages of the body, through
which the catamenia are secreted, are clogged and closed. For the region about the eyes is, of all the head,
that most nearly connected with the generative secretions; a proof of this is that it alone is visibly changed in
sexual intercourse, and those who indulge too much in this are seen to have their eyes sunken in. The reason
is that the nature of the semen is similar to that of the brain, for the material of it is watery (the heat being
acquired later). And the seminal purgations are from the region of the diaphragm, for the first principle of
nature is there, so that the movements from the pudenda are communicated to the chest, and the smells from
the chest are perceived through the respiration.

In men, then, and in other kinds, as said before, such deficiency occurs sporadically, but the whole of the
mule kind is sterile. The reason has not been rightly given by Empedocles and Democritus, of whom the
former expresses himself obscurely, the latter more intelligibly. For they offer their demonstration in the case
of all these animals alike which unite against their affinities. Democritus says that the genital passages of
mules are spoilt in the mother's uterus because the animals from the first are not produced from parents of the
same kind. But we find that though this is so with other animals they are none the less able to generate; yet, if
this were the reason, all others that unite in this manner ought to be barren. Empedocles assigns as his reason
that the mixture of the 'seeds' becomes dense, each of the two seminal fluids out of which it is made being
soft, for the hollows in each fit into the densities of the other, and in such cases a hard substance is formed
out of soft ones, like bronze mingled with tin. Now he does not give the correct reason in the case of bronze
and tin- (we have spoken of them in the Problems)- nor, to take general ground, does he take his principles
from the intelligible. How do the 'hollows' and 'solids' fit into one another to make the mixing, e.g. in the case
of wine and water? This saying is quite beyond us; for how we are to understand the 'hollows' of the wine and
water is too far beyond our perception. Again, when, as a matter of fact, horse is born of horse, ass of ass, and
mule of horse and ass in two ways according as the parents are stallion and she-ass or jackass and mare, why
in the last case does there result something so 'dense' that the offspring is sterile, whereas the offspring of
male and female horse, male and female ass, is not sterile? And yet the generative fluid of the male and
female horse is soft. But both sexes of the horse cross with both sexes of the ass, and the offspring of both
crosses are barren, according to Empedocles, because from both is produced something 'dense', the 'seeds'
being 'soft'. If so, the offspring of stallion and mare ought also to be sterile. If one of them alone united with
the ass, it might be said that the cause of the mule's being unable to generate was the unlikeness of that one to
the generative fluid of the ass; but, as it is, whatever be the character of that generative fluid with which it

8 38

ON THE GENERATION OF ANIMALS

unites in the ass, such it is also in the animal of its own kind. Then, again, the argument is intended to apply
to both male and female mules alike, but the male does generate at seven years of age, it is said; it is the
female alone that is entirely sterile, and even she is so only because she does not complete the development
of the embryo, for a female mule has been known to conceive.

Perhaps an abstract proof might appear to be more plausible than those already given; I call it abstract
because the more general it is the further is it removed from the special principles involved. It runs somewhat
as follows. From male and female of the same species there are born in course of nature male and female of
the same species as the parents, e.g. male and female puppies from male and female dog. From parents of
different species is born a young one different in species; thus if a dog is different from a lion, the offspring
of male dog and lioness or of lion and bitch will be different from both parents. If this is so, then since (1)
mules are produced of both sexes and are not different in species from one another, and (2) a mule is born of
horse and ass and these are different in species from mules, it is impossible that anything should be produced
from mules. For (1) another kind cannot be, because the product of male and female of the same species is
also of the same species, and (2) a mule cannot be, because that is the product of horse and ass which are
different inform, [and it was laid down that from parents different in form is born a different animal]. Now
this theory is too general and empty. For all theories not based on the special principles involved are empty;
they only appear to be connected with the facts without being so really. As geometrical arguments must start
from geometrical principles, so it is with the others; that which is empty may seem to be something, but is
really nothing. Now the basis of this particular theory is not true, for many animals of different species are
fertile with one another, as was said before. So we must not inquire into questions of natural science in this
fashion any more than any other questions; we shall be more likely to find the reason by considering the facts
peculiar to the two kinds concerned, horse and ass. In the first place, each of them, if mated with its own
kind, bears only one young one; secondly, the females are not always able to conceive from the male
(wherefore breeders put the horse to the mare again at intervals). Indeed, both the mare is deficient in
catamenia, discharging less than any other quadruped, and the she-ass does not admit the impregnation, but
ejects the semen with her urine, wherefore men follow flogging her after intercourse. Again the ass is an
animal of cold nature, and so is not wont to be produced in wintry regions because it cannot bear cold, as in
Scythia and the neighbouring country and among the Celts beyond Iberia, for this country also is cold. For
this cause they do not put the jackasses to the females at the equinox, as they do with horses, but about the
summer solstice, in order that the ass-foals may be born in a warm season, for the mothers bear at the same
season as that in which they are impregnated, the period of gestation in both horse and ass being one year.
The animal, then, being, as has been said of such a cold nature, its semen also must be cold. A proof of this is
that if a horse mount a female already impregnated by an ass he does not destroy the impregnation of the ass,
but if the ass be the second to mount her he does destroy that of the horse because of the coldness of his own
semen. When, therefore, they unite with each other, the generative elements are preserved by the heat of the
one of them, that contributed by the horse being the hotter; for in the ass both the semen of the male and the
material contributed by the female are cold, and those of the horse, in both sexes, are hotter. Now when either
hot is added to cold or cold to hot so as to mix, the result is that the embryo itself arising from these is
preserved and thus these animals are fertile when crossed with one another, but the animal produced by them
is no longer fertile but unable to produce perfect offspring.

And in general each of these animals naturally tends towards sterility. The ass has all the disadvantages
already mentioned, and if it should not begin to generate after the first shedding of teeth, it no longer
generates at all; so near is the constitution of the ass to being sterile. The horse is much the same; it tends
naturally towards sterility, and to make it entirely so it is only necessary that its generative secretion should
become colder; now this is what happens to it when mixed with the corresponding secretion of the ass. The
ass in like manner comes very near generating a sterile animal when mated with its own species. Thus when
the difficulty of a cross contrary to nature is added, (when too even in the other case when united with their
own species they with difficulty produce a single young one), the result of the cross, being still more sterile
and contrary to nature, will need nothing further to make it sterile, but will be so of necessity.

8 39

ON THE GENERATION OF ANIMALS

We find also that the bodies of female mules grow large because the matter which is secreted in other animals
to form the catamenia is diverted to growth. But since the period of gestation in such animals is a year, the
mule must not only conceive, if she is to be fertile, but must also nourish the embryo till birth, and this is
impossible if there are no catamenia. But there are none in the mule; the useless part of the nutriment is
discharged with the excretion from the bladder- this is why male mules do not smell to the pudenda of the
females, as do the other solid-hoofed ungulates, but only to the evacuation itself- and the rest of the
nutriment is used up to increase the size of the body. Hence it is sometimes possible for the female to
conceive, as has been known to happen before now, but it is impossible for her to complete the process of
nourishing the embryo and bringing it to birth.

The male, again, may sometimes generate, both because the male sex is naturally hotter than the female and
because it does not contribute any material substance to the mixture. The result in such cases is a 'ginnus', that
is to say, a dwarf mule; for 'ginni' are produced also from the crossing of horse and ass when the embryo is
diseased in the uterus. The ginnus is in fact like the so-called 'metachoera' in swine, for a 'metachoerum' also
is a pig injured in the uterus; this may happen to any pig. The origin of human dwarfs is similar, for these also
have their parts and their whole development injured during gestation, and resemble ginni and metachoera.

Book III

WE have now spoken about the sterility of mules, and about those animals which are viviparous both
externally and within themselves. The generation of the oviparous sanguinea is to a certain extent similar to
that of the animals that walk, and all may be embraced in the same general statement; but in other respects
there are differences in them both as compared with each other and with those that walk. All alike are
generated from sexual union, the male emitting semen into the female. But among the ovipara (1) birds
produce a perfect hard-shelled egg, unless it be injured by disease, and the eggs of birds are all
two-coloured. (2) The cartilaginous fishes, as has been often said already, are oviparous internally but
produce the young alive, the egg changing previously from one part of the uterus to another; and their egg is
soft-shelled and of one colour. One of this class alone does not produce the young from the egg within itself,
the so-called 'frog'; the reason of which must be stated later. (3) All other oviparous fishes produce an egg of
one colour, but this is imperfect, for its growth is completed outside the mother's body by the same cause as
are those eggs which are perfected within.

Concerning the uterus of these classes of animals, what differences there are among them and for what
reasons, has been stated previously. For in some of the viviparous creatures it is high up near the hypozoma,
in others low down by the pudenda; the former in the cartilaginous fishes, the latter in animals both internally
and externally viviparous, such as man and horse and the rest; in the ovipara it is sometimes low, as in the
oviparous fish, and sometimes high, as in birds.

Some embryos are formed in birds spontaneously, which are called wind-eggs and 'zephyria' by some; these
occur in birds which are not given to flight nor rapine but which produce many young, for these birds have
much residual matter, whereas in the birds of prey all such secretion is diverted to the wings and
wing-feathers, while the body is small and dry and hot. (The secretion corresponding in hen-birds to
catamenia, and the semen of the cock, are residues.) Since then both the wings and the semen are made from
residual matter, nature cannot afford to spend much upon both. And for this same reason the birds of prey are
neither given to treading much nor to laying many eggs, as are the heavy birds and those flying birds whose
bodies are bulky, as the pigeon and so forth. For such residual matter is secreted largely in the heavy birds not
given to flying, such as fowls, partridges, and so on, wherefore their males tread often and their females
produce much material. Of such birds some lay many eggs at a time and some lay often; for instance, the

Book III 40

ON THE GENERATION OF ANIMALS

fowl, the partridge, and the Libyan ostrich lay many eggs, while the pigeon family do not lay many but lay
often. For these are between the birds of prey and the heavy ones; they are flyers like the former, but have
bulky bodies like the latter; hence, because they are flyers and the residue is diverted that, way, they lay few
eggs, but they lay often because of their having bulky bodies and their stomachs being hot and very active in
concoction, and because moreover they can easily procure their food, whereas the birds of prey do so with
difficulty.

Small birds also tread often and are very fertile, as are sometimes small plants, for what causes bodily growth
in others turn in them to a seminal residuum. Hence the Adrianic fowls lay most eggs, for because of the
smallness of their bodies the nutriment is used up in producing young. And other birds are more fertile than
game-fowl, for their bodies are more fluid and bulkier, whereas those of game-fowl are leaner and drier,
since a passionate spirit is found rather in such bodies as the latter. Moreover the thinness and weakness of
the legs contribute to making the former class of birds naturally inclined to tread and to be fertile, as we find
also in the human species; for the nourishment which otherwise goes to the legs is turned in such into a
seminal secretion, what Nature takes from the one place being added at the other. Birds of prey, on the
contrary, have a strong walk and their legs are thick owing to their habits, so that for all these reasons they
neither tread nor lay much. The kestrel is the most fertile; for this is nearly the only bird of prey which drinks,
and its moisture, both innate and acquired, along with its heat is favourable to generative products. Even this
bird does not lay very many eggs, but four at the outside.

The cuckoo, though not a bird of prey, lays few eggs, because it is of a cold nature, as is shown by the
cowardice of the bird, whereas a generative animal should be hot and moist. That it is cowardly is plain, for it
is pursued by all the birds and lays eggs in the nests of others.

The pigeon family are in the habit of laying two for the most part, for they neither lay one (no bird does
except the cuckoo, and even that sometimes lays two) nor yet many, but they frequently produce two, or three
at the most generally two, for this number lies between one and many.

It is plain from the facts that with the birds that lay many eggs the nutriment is diverted to the semen. For
most trees, if they bear too much fruit, wither away after the crop when nutriment is not reserved for
themselves, and this seems to be what happens to annuals, as leguminous plants, corn, and the like. For they
consume all their nutriment to make seed, their kind being prolific. And some fowls after laying too much, so
as even to lay two eggs in a day, have died after this. For both the birds the plants become exhausted, and this
condition is an excess of secretion of residual matter. A similar condition is the cause of the later sterility of
the lioness, for at the first birth she produces five or six, then in the next year four, and again three cubs, then
the next number down to one, then none at all, showing that the residue is being used up and the generative
secretion is failing along with the advance of years.

We have now stated in which birds wind-eggs are found, and also what sort of birds lay many eggs or few,
and for what reasons. And wind-eggs, as said before, come into being because while it is the material for
generation that exists in the female of all animals, birds have no discharge of catamenia like viviparous
sanguinea (for they occur in all these latter, more in some, less in others, and in some only enough in quantity
just to mark the class). The same applies to fish as to birds, and so in them as in birds is found an embryonic
formation without impregnation, but it is less obvious because their nature is colder. The secretion
corresponding to the catamenia of vivipara is formed in birds at the appropriate season for the discharge of
superfluous matter, and, because the region near the hypozoma is hot, it is perfected so far as size is
concerned, but in birds and fishes alike it is imperfect for generation without the seminal fluid of the male;
the cause of this has been previously given. Wind-eggs are not formed in the flying birds, for the same
reason as prevents their laying many eggs; for the residual matter in birds of prey is small, and they need the
male to give an impulse for the discharge of it. The wind-eggs are produced in greater numbers than the
impregnated but smaller in size for one and the same reason; they are smaller in size because they are

Book III 41

ON THE GENERATION OF ANIMALS

imperfect, and because they are smaller in size they are more in number. They are less pleasant for food
because they are less concocted, for in all foods the concocted is more agreeable. It has been sufficiently
observed, then, that neither birds' nor fishes' eggs are perfected for generation without the males. As for
embryos being formed in fish also (though in a less degree) without the males, the fact has been observed
especially in river fish, for some are seen to have eggs from the first, as has been written in the Enquiries
concerning them. And generally speaking in the case of birds even the impregnated eggs are not wont for the
most part to attain their full growth unless the hen be trodden continually. The reason of this is that just as
with women intercourse with men draws down the secretion of the catamenia (for the uterus being heated
attracts the moisture and the passages are opened), so this happens also with birds; the residual matter
corresponding to the catamenia advances a little at a time, and is not discharged externally, because its
amount is small and the uterus is high up by the hypozoma, but trickles together into the uterus itself. For as
the embryo of the vivipara grows by means of the umbilical cord, so the egg grows through this matter
flowing to it through the uterus. For when once the hens have been trodden, they all continue to have eggs
almost without intermission, though very small ones. Hence some are wont to speak of wind-eggs as not
coming into being independently but as mere relics from a previous impregnation. But this is a false view, for
sufficient observations have been made of their arising without impregnation in chickens and goslings. Also
the female partridges which are taken out to act as decoys, whether they have ever been impregnated or not,
immediately on smelling the male and hearing his call, become filled with eggs in the latter case and lay them
in the former. The reason why this happens is the same as in men and quadrupeds, for if their bodies chance
to be in rut they emit semen at the mere sight of the female or at a slight touch. And such birds are of a
lascivious and fertile nature, so that the impulse they need is but small when they are in this excited
condition, and the secreting activity takes place quickly in them, wind-eggs forming in the unimpregnated
and the eggs in those which have been impregnated growing and reaching perfection swiftly.

Among creatures that lay eggs externally birds produce their egg perfect, fish imperfect, but the eggs of the
latter complete their growth outside as has been said before. The reason is that the fish kind is very fertile;
now it is impossible for many eggs to reach completion within the mother and therefore they lay them
outside. They are quickly discharged, for the uterus of externally oviparous fishes is near the generative
passage. While the eggs of birds are two-coloured, those of all fish are one-coloured. The cause of the
double colour may be seen from considering the power of each of the two parts, the white and the yolk. For
the matter of the egg is secreted from the blood [No bloodless animal lays eggs,] and that the blood is the
material of the body has been often said already. The one part, then, of the egg is nearer the form of the
animal coming into being, that is the hot part; the more earthy part gives the substance of the body and is
further removed. Hence in all two-coloured eggs the animal receives the first principle of generation from
the white (for the vital principle is in that which is hot), but the nutriment from the yolk. Now in animals of a
hotter nature the part from which the first principle arises is separated off from the part from which comes the
nutriment, the one being white and the other yellow, and the white and pure is always more than the yellow
and earthy; but in the moister and less hot the yolk is more in quantity and more fluid. This is what we find in
lake birds, for they are of a moister nature and are colder than the land birds, so that the so-called 'lecithus' or
yolk in the eggs of such birds is large and less yellow because the white is less separated off from it. But
when we come to the ovipara which are both of a cold nature and also moister (such is the fish kind) we find
the white not separated at all because of the small size of the eggs and the quantity of the cold and earthy
matter; therefore all fish eggs are of one colour, and white compared with yellow, yellow compared with
white. Even the wind-eggs of birds have this distinction of colour, for they contain that out of which will
come each of the two parts, alike that whence arises the principle of life and that whence comes the
nutriment; only both these are imperfect and need the influence of the male in addition; for wind-eggs
become fertile if impregnated by the male within a certain period. The difference in colour, however, is not
due to any difference of sex, as if the white came from the male, the yolk from the female; both on the
contrary come from the female, but the one is cold, the other hot. In all cases then where the hot part is
considerable it is separated off, but where it is little it cannot be so; hence the eggs of such animals, as has
been said, are of one colour. The semen of the male only puts them into form; and therefore at first the egg in

Book III 42

ON THE GENERATION OF ANIMALS

birds appears white and small, but as it advances it is all yellow as more of the sanguineous material is
continually mixed with it; finally as the hot part is separated the white takes up a position all round it and
equally distributed on all sides, as when a liquid boils; for the white is naturally liquid and contains in itself
the vital heat; therefore it is separated off all round, but the yellow and earthy part is inside. And if we
enclose many eggs together in a bladder or something of the kind and boil them over a fire so as not to make
the movement of the heat quicker than the separation of the white and yolk in the eggs, then the same process
takes place in the whole mass of the eggs as in a single egg, all the yellow part coming into the middle and
the white surrounding it.

We have thus stated why some eggs are of one colour and others of two.

The principle of the male is separated off in eggs at the point where the egg is attached to the uterus, and the
reason why the shape of two-coloured eggs is unsymmetrical, and not perfectly round but sharper at one end,
is that the part of the white in which is contained this principle must differ from the rest. Therefore the egg is
harder at this point than below, for it is necessary to shelter and protect this principle. And this is why the
sharp end of the egg comes out of the hen later than the blunt end; for the part attached to the uterus comes
out later, and the egg is attached at the point where is the said principle, and the principle is in the sharp end.
The same is the case also in the seeds of plants; the principle of the seed is attached sometimes to the twig,
sometimes to the husk, sometimes to the pericarp. This is plain in the leguminous plants, for where the two
cotyledons of beans and of similar seeds are united, there is the seed attached to the parent plant, and there is
the principle of the seed.

A difficulty may be raised about the growth of the egg; how is it derived from the uterus? For if animals
derive their nutriment through the umbilical cord, through what do eggs derive it? They do not, like a scolex,
acquire their growth by their own means. If there is anything by which they are attached to the uterus, what
becomes of this when the egg is perfected? It does not come out with the egg as the cord does with animals;
for when its egg is perfected the shell forms all round it. This problem is rightly raised, but it is not observed
that the shell is at first only a soft membrane, and that it is only after the egg is perfected that it becomes hard
and brittle; this is so nicely adjusted that it is still soft when it comes out (for otherwise it would cause pain in
laying), but no sooner has it come out than it is fixed hard by cooling, the moisture quickly evaporating
because there is but little of it, and the earthy part remaining. Now at first a certain part of this membrane at
the sharp end of eggs resembles an umbilical cord, and projects like a pipe from them while they are still
small. It is plainly visible in small aborted eggs, for if the bird be drenched with water or suddenly chilled in
any other way and cast out the egg too soon, it appears still sanguineous and with a small tail like an
umbilical cord running through it. As the egg becomes larger this is more twisted round and becomes smaller,
and when the egg is perfected this end is the sharp end. Under this is the inner membrane which separates the
white and the yolk from this. When the egg is perfected, the whole of it is set free, and naturally the umbilical
cord does not appear, for it is now the extreme end of the egg itself.

The egg is discharged in the opposite way from the young of vivipara; the latter are born head-first, the part
where is the first principle leading, but the egg is discharged as it were feet first; the reason of this being what
has been stated, that the egg is attached to the uterus at the point where is the first principle.

The young bird is produced out of the egg by the mother's incubating and aiding the concoction, the creature
developing out of part of the egg, and receiving growth and completion from the remaining part. For Nature
not only places the material of the creature in the egg but also the nourishment sufficient for its growth; for
since the mother bird cannot perfect her young within herself she produces the nourishment in the egg along
with it. Whereas the nourishment, what is called milk, is produced for the young of vivipara in another part,

2 43

ON THE GENERATION OF ANIMALS

in the breasts, Nature does this for birds in the egg. The opposite, however, is the case to what people think
and what is asserted by Alcmaeon of Crotona. For it is not the white that is the milk, but the yolk, for it is this
that is the nourishment of the chick, whereas they think it is the white because of the similarity of colour.

The chick then, as has been said, comes into being by the incubation of the mother; yet if the temperature of
the season is favourable, or if the place in which the eggs happen to lie is warm, the eggs are sufficiently
concocted without incubation, both those of birds and those of oviparous quadrupeds. For these all lay their
eggs upon the ground, where they are concocted by the heat in the earth. Such oviparous quadrupeds as do
visit their eggs and incubate do so rather for the sake of protecting them than of incubation.

The eggs of these quadrupeds are formed in the same way as those of birds, for they are hard-shelled and
two-coloured, and they are formed near the hypozoma as are those of birds, and in all other respects
resemble them both internally and externally, so that the inquiry into their causes is the same for all. But
whereas the eggs of quadrupeds are hatched out by the mere heat of the weather owing to their strength, those
of birds are more exposed to destruction and need the mother-bird. Nature seems to wish to implant in
animals a special sense of care for their young: in the inferior animals this lasts only to the moment of giving
birth to the incompletely developed animal; in others it continues till they are perfect; in all that are more
intelligent, during the bringing up of the young also. In those which have the greatest portion in intelligence
we find familiarity and love shown also towards the young when perfected, as with men and some
quadrupeds; with birds we find it till they have produced and brought up their young, and therefore if the
hens do not incubate after laying they get into worse condition, as if deprived of something natural to them.

The young is perfected within the egg more quickly in sunshiny weather, the season aiding in the work, for
concoction is a kind of heat. For the earth aids in the concoction by its heat, and the brooding hen does the
same, for she applies the heat that is within her. And it is in the hot season, as we should expect, that the eggs
are more apt to be spoilt and the so-called 'uria' or rotten eggs are produced; for just as wines turn sour in the
heats from the sediment rising (for this is the cause of their being spoilt), so is it with the yolk in eggs, for the
sediment and yolk are the earthy part in each case, wherefore the wine becomes turbid when the sediment
mixes with it, and the like applies to the eggs that are spoiling because of the yolk. It is natural then that such
should be the case with the birds that lay many eggs, for it is not easy to give the fitting amount of heat to all,
but (while some have too little) others have too much and this makes them turbid, as it were by putrefaction.
But this happens none the less with the birds of prey though they lay few eggs, for often one of the two
becomes rotten, and the third practically always, for being of a hot nature they make the moisture in the eggs
to overboil so to say. For the nature of the white is opposed to that of the yolk; the yolk congeals in frosts but
liquefies on heating, and therefore it liquefies on concoction in the earth or by reason of incubation, and
becoming liquid serves as nutriment for the developing chick. If exposed to heat and roasted it does not
become hard, because though earthy in nature it is only so in the same way as wax is; accordingly on heating
too much the eggs become watery and rotten, [if they be not from a liquid residue]. The white on the contrary
is not congealed by frost but rather liquefies (the reason of which has been stated before), but on exposure to
heat becomes solid. Therefore being concocted in the development of the chick it is thickened. For it is from
this that the young is formed (whereas the yolk turns to nutriment) and it is from this that the parts derive
their growth as they are formed one after another. This is why the white and the yolk are separated by
membranes, as being different in nature. The precise details of the relation of the parts to one another both at
the beginning of generation and as the animals are forming, and also the details of the membranes and
umbilical cords, must be learnt from what has been written in the Enquiries; for the present investigation it is
sufficient to understand this much clearly, that, when the heart has been first formed and the great
blood-vessel has been marked off from it, two umbilical cords run from the vessel, the one to the membrane
which encloses the yolk, the other to the membrane resembling a chorion which surrounds the whole embryo;
this latter runs round on the inside of the membrane of the shell. Through the one of these the embryo
receives the nutriment from the yolk, and the yolk becomes larger, for it becomes more liquid by heating.
This is because the nourishment, being of a material character in its first form, must become liquid before it

2 44

ON THE GENERATION OF ANIMALS

can be absorbed, just as it is with plants, and at first this embryo, whether in an egg or in the mother's uterus,
lives the life of a plant, for it receives its first growth and nourishment by being attached to something else.

The second umbilical cord runs to the surrounding chorion. For we must understand that, in the case of
animals developed in eggs, the chick has the same relation to the yolk as the embryo of the vivipara has to the
mother so long as it is within the mother (for since the nourishment of the embryo of the ovipara is not
completed within the mother, the embryo takes part of it away from her). So also the relation of the chick to
the outermost membrane, the sanguineous one, is like that of the mammalian embryo to the uterus. At the
same time the egg-shell surrounds both the yolk and the membrane analogous to the uterus, just as if it
should be put round both the embryo itself and the whole of the mother, in the vivipara. This is so because
the embryo must be in the uterus and attached to the mother. Now in the vivipara the uterus is within the
mother, but in the ovipara it is the other way about, as if one should say that the mother was in the uterus, for
that which comes from the mother, the nutriment, is the yolk. The reason is that the process of nourishment is
not completed within the mother.

As the creature grows the umbilicus running the chorion collapses first, because it is here that the young is to
come out; what is left of the yolk, and the umbilical cord running to the yolk, collapse later. For the young
must have nourishment as soon as it is hatched; it is not nursed by the mother and cannot immediately
procure its nourishment for itself; therefore the yolk enters within it along with its umbilicus and the flesh
grows round it.

This then is the manner in which animals produced from perfect eggs are hatched in all those, whether birds
or quadrupeds, which lay the egg with a hard shell. These details are plainer in the larger creatures; in the
smaller they are obscure because of the smallness of the masses concerned.

The class of fishes is also oviparous. Those among them which have the uterus low down lay an imperfect
egg for the reason previously given,' but the so-called 'selache' or cartilaginous fishes produce a perfect egg
within themselves but are externally viviparous except one which they call the 'frog'; this alone lays a perfect
egg externally. The reason is the nature of its body, for its head is many times as large as the rest of the body
and is spiny and very rough. This is also why it does not receive its young again within itself nor produce
them alive to begin with, for as the size and roughness of the head prevents their entering so it would prevent
their exit. And while the egg of the cartilaginous fishes is soft-shelled (for they cannot harden and dry its
circumference, being colder than birds), the egg of the frog-fish alone is solid and firm to protect it outside,
but those of the rest are of a moist and soft nature, for they are sheltered within and by the body of the
mother.

The young are produced from the egg in the same way both with those externally perfected (the frog-fishes)
and those internally, and the process in these eggs is partly similar to, partly different from that in birds' eggs.
In the first place they have not the second umbilicus which runs to the chorion under the surrounding shell.
The reason of this is that they have not the surrounding shell, for it is no use to them since the mother shelters
them, and the shell is a protection to the eggs against external injury between laying and hatching out.
Secondly, the process in these also begins on the surface of the egg but not where it is attached to the uterus,
as in birds, for the chick is developed from the sharp end and that is where the egg was attached. The reason
is that the egg of birds is separated from the uterus before it is perfected, but in most though not all
cartilaginous fishes the egg is still attached to the uterus when perfect. While the young develops upon the
surface the egg is consumed by it just as in birds and the other animals detached from the uterus, and at last
the umbilicus of the now perfect fish is left attached to the uterus. The like is the case with all those whose
eggs are detached from the uterus, for in some of them the egg is so detached when it is perfect.

3 45

ON THE GENERATION OF ANIMALS

The question may be asked why the development of birds and cartilaginous fishes differs in this respect. The
reason is that in birds the white and yolk are separate, but fish eggs are one-coloured, the corresponding
matter being completely mixed, so that there is nothing to stop the first principle being at the opposite end,
for the egg is of the same nature both at the point of attachment and at the opposite end, and it is easy to draw
the nourishment from the uterus by passages running from this principle. This is plain in the eggs which are
not detached, for in some of the cartilaginous fish the egg is not detached from the uterus, but is still
connected with it as it comes downwards with a view to the production of the young alive; in these the young
fish when perfected is still connected by the umbilicus to the uterus when the egg has been consumed. From
this it is clear that previously also, while the egg was still round the young, the passages ran to the uterus.
This happens as we have said in the 'smooth hound'.

In these respects and for the reasons given the development of cartilaginous fishes differs from that of birds,
but otherwise it takes place in the same way. For they have the one umbilicus in like manner as that of birds
connecting with the yolk,- only in these fishes it connects with the whole egg (for it is not divided into white
and yolk but all one-coloured),- and get their nourishment from this, and as it is being consumed the flesh in
like manner encroaches upon and grows round it.

Such is the process of development in those fish that produce a perfect egg within themselves but are
externally viviparous.

Most of the other fish are externally oviparous, all laying an imperfect egg except the frog-fish; the reason of
this exception has been previously stated, and the reason also why the others lay imperfect eggs. In these also
the development from the egg runs on the same lines as that of the cartilaginous and internally oviparous
fishes, except that the growth is quick and from small beginnings and the outside of the egg is harder. The
growth of the egg is like that of a scolex, for those animals which produce a scolex give birth to a small thing
at first and this grows by itself and not through any attachment to the parent. The reason is similar to that of
the growth of yeast, for yeast also grows great from a small beginning as the more solid part liquefies and the
liquid is aerated. This is effected in animals by the nature of the vital heat, in yeasts by the heat of the juice
commingled with them. The eggs then grow of necessity through this cause (for they have in them
superfluous yeasty matter), but also for the sake of a final cause, for it is impossible for them to attain their
whole growth in the uterus because these animals have so many eggs. Therefore are they very small when set
free and grow quickly, small because the uterus is narrow for the multitude of the eggs, and growing quickly
that the race may not perish, as it would if much of the time required for the whole development were spent
in this growth; even as it is most of those laid are destroyed before hatching. Hence the class of fish is
prolific, for Nature makes up for the destruction by numbers. Some fish actually burst because of the size of
the eggs, as the fish called 'belone', for its eggs are large instead of numerous, what Nature has taken away in
number being added in size.

So much for the growth of such eggs and its reason.

A proof that these fish also are oviparous is the fact that even viviparous fish, such as the cartilaginous, are
first internally oviparous, for hence it is plain that the whole class of fishes is oviparous. Where, however,
both sexes exist and the eggs are produced in consequence of impregnation, the eggs do not arrive at
completion unless the male sprinkle his milt upon them. Some erroneously assert that all fish are female
except in the cartilaginous fishes, for they think that the females of fish differ from what are supposed to be
males only in the same way as in those plants where the one bears fruit but the other is fruitless, as olive and

4 46

ON THE GENERATION OF ANIMALS

oleaster, fig and caprifig. They think the like applies to fish except the cartilaginous, for they do not dispute
the sexes in these. And yet there is no difference in the males of cartilaginous fishes and those belonging to
the oviparous class in respect of the organs for the milt, and it is manifest that semen can be squeezed out of
males of both classes at the right season. The female also has a uterus. But if the whole class were females
and some of them unproductive (as with mules in the class of bushy-tailed animals), then not only should
those which lay eggs have a uterus but also the others, only the uterus of the latter should be different from
that of the former. But, as it is, some of them have organs for milt and others have a uterus, and this
distinction obtains in all except two, the erythrinus and the channa, some of them having the milt organs,
others a uterus. The difficulty which drives some thinkers to this conclusion is easily solved if we look at the
facts. They say quite correctly that no animal which copulates produces many young, for of all those that
generate from themselves perfect animals or perfect eggs none is prolific on the same scale as the oviparous
fishes, for the number of eggs in these is enormous. But they had overlooked the fact that fish-eggs differ
from those of birds in one circumstance. Birds and all oviparous quadrupeds, and any of the cartilaginous fish
that are oviparous, produce a perfect egg, and it does not increase outside of them, whereas the eggs of fish
are imperfect and do so complete their growth. Moreover the same thing applies to cephalopods also and
Crustacea, yet these animals are actually seen copulating, for their union lasts a long time, and it is plain in
these cases that the one is male and the other has a uterus. Finally, it would be strange if this distinction did
not exist in the whole class, just as male and female in all the vivipara. The cause of the ignorance of those
who make this statement is that the differences in the copulation and generation of various animals are of all
kinds and not obvious, and so, speculating on a small induction, they think the same must hold good in all
cases.

So also those who assert that conception in female fishes is caused by their swallowing the semen of the male
have not observed certain points when they say this. For the males have their milt and the females their eggs
at about the same time of year, and the nearer the female is to laying the more abundant and the more liquid is
the milt formed in the male. And just as the increase of the milt in the male and of the roe in the female takes
place at the same time, so is it also with their emission, for neither do the females lay all their eggs together,
but gradually, nor do the males emit all the milt at once. All these facts are in accordance with reason. For
just as the class of birds in some cases has eggs without impregnation, but few and seldom, impregnation
being generally required, so we find the same thing, though to a less degree, in fish. But in both classes these
spontaneous eggs are infertile unless the male, in those kinds where the male exists, shed his fluid upon them.
Now in birds this must take place while the eggs are still within the mother, because they are perfect when
discharged, but in fish, because the eggs are imperfect and complete their growth outside the mother in all
cases, those outside are preserved by the sprinkling of the milt over them, even if they come into being by
impregnation, and here it is that the milt of the males is used up. Therefore it comes down the ducts and
diminishes in quantity at the same time as this happens to the eggs of the females, for the males always attend
them, shedding their milt upon the eggs as they are laid. Thus then they are male and female, and all of them
copulate (unless in any kind the distinction of sex does not exist), and without the semen of the male no such
animal comes into being.

What helps in the deception is also the fact that the union of such fishes is brief, so that it is not observed
even by many of the fishermen, for none of them ever watches anything of the sort for the sake of knowledge.
Nevertheless their copulation has been seen, for fish [when the tail part does not prevent it] copulate like the
dolphins by throwing themselves alongside of one another. But the dolphins take longer to get free again,
whereas such fishes do so quickly. Hence, not seeing this, but seeing the swallowing of the milt and the eggs,
even the fishermen repeat the same simple tale, so much noised abroad, as Herodotus the storyteller, as if fish
were conceived by the mother's swallowing the milt,- not considering that this is impossible. For the passage
which enters by way of the mouth runs to the intestines, not to the uterus, and what goes into the intestines
must be turned into nutriment, for it is concocted; the uterus, however, is plainly full of eggs, and from
whence did they enter it?

ON THE GENERATION OF ANIMALS

A similar story is told also of the generation of birds. For there are some who say that the raven and the ibis
unite at the mouth, and among quadrupeds that the weasel brings forth its young by the mouth; so say
Anaxagoras and some of the other physicists, speaking too superficially and without consideration.
Concerning the birds, they are deceived by a false reasoning, because the copulation of ravens is seldom seen,
but they are often seen uniting with one another with their beaks, as do all the birds of the raven family; this
is plain with domesticated jackdaws. Birds of the pigeon kind do the same, but, because they also plainly
copulate, therefore they have not had the same legend told of them. But the raven family is not amorous, for
they are birds that produce few young, though this bird also has been seen copulating before now. It is a
strange thing, however, that these theorists do not ask themselves how the semen enters the uterus through the
intestine, which always concocts whatever comes into it, as the nutriment; and these birds have a uterus like
others, and eggs are found them near the hypozoma. And the weasel has a uterus in like manner to the other
quadrupeds; by what passage is the embryo to get from it to the mouth? But this opinion has arisen because
the young of the weasel are very small like those of the other fissipeds, of which we shall speak later, and
because they often carry the young about in their mouths.

Much deceived also are those who make a foolish statement about the trochus and the hyena. Many say that
the hyena, and Herodorus the Heracleot says that the trochus, has two pudenda, those of the male and of the
female, and that the trochus impregnates itself but the hyena mounts and is mounted in alternate years. This is
untrue, for the hyena has been seen to have only one pudendum, there being no lack of opportunity for
observation in some districts, but hyenas have under the tail a line like the pudendum of the female. Both
male and female have such a mark, but the males are taken more frequently; this casual observation has given
rise to this opinion. But enough has been said of this.

Touching the generation of fish, the question may be raised, why it is that in the cartilaginous fish neither the
females are seen discharging their eggs nor the males their milt, whereas in the non-viviparous fishes this is
seen in both sexes. The reason is that the whole cartilaginous class do not produce much semen, and further
the females have their uterus near hypozoma. For the males and females of the one class of fish differ from
the males and females of the other class in like manner, for the cartilaginous are less productive of semen.
But in the oviparous fish, as the females lay their eggs on account of their number, so do the males shed their
milt on account of its abundance. For they have more milt than just what is required for copulation, as Nature
prefers to expend the milt in helping to perfect the eggs, when the female has deposited them, rather than in
forming them at first. For as has been said both further back and in our recent discussions, the eggs of birds
are perfected internally but those of fish externally. The latter, indeed, resemble in a way those animals which
produce a scolex, for the product discharged by them is still more imperfect than a fish's egg. It is the male
that brings about the perfection of the egg both of birds and of fishes, only in the former internally, as they
are perfected internally, and in the latter externally, because the egg is imperfect when deposited; but the
result is the same in both cases.

In birds the wind-eggs become fertile, and those previously impregnated by one kind of cock change their
nature to that of the later cock. And if the eggs be behindhand in growth, then, if the same cock treads the hen
again after leaving off treading for a time, he causes them to increase quickly, not, however, at any period
whatever of their development, but if the treading take place before the egg changes so far that the white
begins to separate from the yolk. But in the eggs of fishes no such limit of time has been laid down, but the
males shed their milt quickly upon them to preserve them. The reason is that these eggs are not
two-coloured, and hence there is no such limit of time fixed with them as with those of birds. This fact is
what we should expect, for by the time that the white and yolk are separated off from one another, the birds

6 48

ON THE GENERATION OF ANIMALS

egg already contains the principle that comes from the male parent... for the male contributes to this.

Wind-eggs, then, participate in generation so far as is possible for them. That they should be perfected into
an animal is impossible, for an animal requires sense-perception; but the nutritive faculty of the soul is
possessed by females as well as males, and indeed by all living things, as has been often said, wherefore the
egg itself is perfect only as the embryo of a plant, but imperfect as that of an animal. If, then, there had been
no male sex in the class of birds, the egg would have been produced as it is in some fishes, if indeed there is
any kind of fish of such a nature as to generate without a male; but it has been said of them before that this
has not yet been satisfactorily observed. But as it is both sexes exist in all birds, so that, considered as a plant,
the egg is perfect, but in so far as it is not a plant it is not perfect, nor does anything else result from it; for
neither has it come into being simply like a real plant nor from copulation like an animal. Eggs, however,
produced from copulation but already separated into white and yolk take after the first cock; for they already
contain both principles, which is why they do not change again after the second impregnation.

The young are produced in the same way also by the cephalopoda, e.g. sepias and the like, and by the
Crustacea, e.g. carabi and their kindred, for these also lay eggs in consequence of copulation, and the male has
often been seen uniting with the female. Therefore those who say that all fish are female and lay eggs without
copulation are plainly speaking unscientifically from this point of view also. For it is a wonderful thing to
suppose that the former animals lay eggs in consequence of copulation and that fish do not; if again they were
unaware of this, it is a sign of ignorance. The union of all these creatures lasts a considerable time, as in
insects, and naturally so, for they are bloodless and therefore of a cold nature.

In the sepias and calamaries or squids the eggs appear to be two, because the uterus is divided and appears
double, but that of the poulps appears to be single. The reason is that the shape of the uterus in the poulp is
round in form and spherical, the cleavage being obscure when it is filled with eggs. The uterus of the carabi is
also bifid. All these animals also lay an imperfect egg for the same reason as fishes. In the carabi and their
like the females produce their eggs so as to keep them attached to themselves, which is why the side-flaps of
the females are larger than those of the males, to protect the eggs; the cephalopoda lay them away from
themselves. The males of the cephalopoda sprinkle their milt over the females, as the male fish do over the
eggs, and it becomes a sticky and glutinous mass, but in the carabi and their like nothing of the sort has been
seen or can be naturally expected, for the egg is under the female and is hard-shelled. Both these eggs and
those of the cephalopoda grow after deposition like those of fishes.

The sepia while developing is attached to the egg by its front part, for here alone is it possible, because this
animal alone has its front and back pointing in the same direction. For the position and attitude of the young
while developing you must look at the Enquiries.

We have now spoken of the generation of other animals, those that walk, fly, and swim; it remains to speak of
insects and testacea according to the plan laid down. Let us begin with the insects. It was observed previously
that some of these are generated by copulation, others spontaneously, and besides this that they produce a
scolex, and why this is so. For pretty much all creatures seem in a certain way to produce a scolex first, since
the most imperfect embryo is of such a nature; and in all animals, even the viviparous and those that lay a
perfect egg, the first embryo grows in size while still undifferentiated into parts; now such is the nature of the
scolex. After this stage some of the ovipara produce the egg in a perfect condition, others in an imperfect, but
it is perfected outside as has been often stated of fish. With animals internally viviparous the embryo
becomes egg-like in a certain sense after its original formation, for the liquid is contained in a fine

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membrane, just as if we should take away the shell of the egg, wherefore they call the abortion of an embryo
at that stage an 'efflux'.

Those insects which generate at all generate a scolex, and those which come into being spontaneously and not
from copulation do so at first from a formation this nature. I say that the former generate a scolex, for we
must put down caterpillars also and the product of spiders as a sort of scolex. And yet some even of these and
many of the others may be thought to resemble eggs because of their round shape, but we must not judge by
shapes nor yet by softness and hardness (for what is produced by some is hard), but by the fact that the whole
of them is changed into the body of the creature and the animal is not developed from a part of them. All
these products that are of the nature of a scolex, after progressing and acquiring their full size, become a sort
of egg, for the husk about them hardens and they are motionless during this period. This is plain in the scolex
of bees and wasps and in caterpillars. The reason of this is that their nature, because of its imperfection,
oviposits as it were before the right time, as if the scolex, while still growing in size, were a soft egg. Similar
to this is also what happens with all other insects which come into being without copulation in wool and other
such materials and in water. For all of them after the scolex stage become immovable and their integument
dries round them, and after this the latter bursts and there comes forth as from an egg an animal perfected in
its second metamorphosis, most of those which are not aquatic being winged.

Another point is quite natural, which may wondered at by many. Caterpillars at first take nourishment, but
after this stage do so no longer, but what is called by some the chrysalis is motionless. The same applies to
the scolex of wasps and bees, but after this comes into being the so-called nymph.... and have nothing of the
kind. For an egg is also of such a nature that when it has reached perfection it grows no more in size, but at
first it grows and receives nourishment until it is differentiated and becomes a perfect egg. Sometimes the
scolex contains in itself the material from which it is nourished and obtains such an addition to its size, e.g. in
bees and wasps; sometimes it gets its nourishment from outside itself, as caterpillars and some others.

It has thus been stated why such animals go through a double development and for what reason they become
immovable again after moving. And some of them come into being by copulation, like birds and vivipara and
most fishes, others spontaneously, like some plants.

There is much difficulty about the generation of bees. If it is really true that in the case of some fishes there is
such a method of generation that they produce eggs without copulation, this may well happen also with bees,
to judge from appearances. For they must (1) either bring the young brood from elsewhere, as some say, and
if so the young must either be spontaneously generated or produced by some other animal, or (2) they must
generate them themselves, or (3) they must bring some and generate others, for this also is maintained by
some, who say that they bring the young of the drones only. Again, if they generate them it must be either
with or without copulation; if the former, then either (1) each kind must generate its own kind, or (2) some
one kind must generate the others, or (3) one kind must unite with another for the purpose (I mean for
instance (1) that bees may be generated from the union of bees, drones from that of drones, and kings from
that of kings, or (2) that all the others may be generated from one, as from what are called kings and leaders,
or (3) from the union of drones and bees, for some say that the former are male, the latter female, while
others say that the bees are male and the drones female). But all these views are impossible if we reason first
upon the facts peculiar to bees and secondly upon those which apply more generally to other animals also.

For if they do not generate the young but bring them from elsewhere, then bees ought to come into being
also, if the bees did not carry them off, in the places from which the old bees carry the germs. For why, if new
bees come into existence when the germs are transported, should they not do so if the germs are left there?
They ought to do so just as much, whether the germs are spontaneously generated in the flowers or whether

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some animal generates them. And if the germs were of some other animal, then that animal ought to be
produced from them instead of bees. Again, that they should collect honey is reasonable, for it is their food,
but it is strange that they should collect the young if they are neither their own offspring nor food. With what
object should they do so? for all animals that trouble themselves about the young labour for what appears to
be their own offspring.

But, again, it is also unreasonable to suppose that the bees are female and the drones male, for Nature does
not give weapons for fighting to any female, and while the drones are stingless all the bees have a sting. Nor
is the opposite view reasonable, that the bees are male and the drones female, for no males are in the habit of
working for their offspring, but as it is the bees do this. And generally, since the brood of the drones is found
coming into being among them even if there is no mature drone present, but that of the bees is not so found
without the presence of the kings (which is why some say that the young of the drones alone is brought in
from outside), it is plain that they are not produced from copulation, either (1) of bee with bee or drone with
drone or (2) of bees with drones. (That they should import the brood of the drones alone is impossible for the
reasons already given, and besides it is unreasonable that a similar state of things should not prevail with all
the three kinds if it prevails with one.) Then, again, it is also impossible that the bees themselves should be
some of them male and some female, for in all kinds of animals the two sexes differ. Besides they would in
that case generate their own kind, but as it is their brood is not found to come into being if the leaders are not
among them, as men say. And an argument against both theories, that the young are generated by union of the
bees with one another or with the drones, separately or with one another, is this: none of them has ever yet
been seen copulating, whereas this would have often happened if the sexes had existed in them. It remains
then, if they are generated by copulation at all, that the kings shall unite to generate them. But the drones are
found to come into being even if no leaders are present, and it is not possible that the bees should either
import their brood or themselves generate them by copulation. It remains then, as appears to be the case in
certain fishes, that the bees should generate the drones without copulation, being indeed female in respect of
generative power, but containing in themselves both sexes as plants do. Hence also they have the instrument
of offence, for we ought not to call that female in which the male sex is not separated. But if this is found to
be the case with drones, if they come into being without copulation, then as it is necessary that the same
account should be given of the bees and the kings and that they also should be generated without copulation.
Now if the brood of the bees had been found to come into being among them without the presence of the
kings, it would necessarily follow that the bees also are produced from bees themselves without copulation,
but as it is, since those occupied with the tendance of these creatures deny this, it remains that the kings must
generate both their own kind and the bees.

As bees are a peculiar and extraordinary kind of animal so also their generation appears to be peculiar. That
bees should generate without copulation is a thing which may be paralleled in other animals, but that what
they generate should not be of the same kind is peculiar to them, for the erythrinus generates an erythrinus
and the channa a channa. The reason is that bees themselves are not generated like flies and similar creatures,
but from a kind different indeed but akin to them, for they are produced from the leaders. Hence in a sort of
way their generation is analogous. For the leaders resemble the drones in size and the bees in possessing a
sting; so the bees are like them in this respect, and the drones are like them in size. For there must needs be
some overlapping unless the same kind is always to be produced from each; but this is impossible, for at that
rate the whole class would consist of leaders. The bees, then, are assimilated to them their power of
generation, the drones in size; if the latter had had a sting also they would have been leaders, but as it is this
much of the difficulty has been solved, for the leaders are like both kinds at once, like the bees in possessing
a sting, like the drones in size.

But the leaders also must be generated from something. Since it is neither from the bees nor from the drones,
it must be from their own kind. The grubs of the kings are produced last and are not many in number.

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Thus what happens is this: the leaders generate their own kind but also another kind, that of the bees; the bees
again generate another kind, the drones, but do not also generate their own kind, but this has been denied
them. And since what is according to Nature is always in due order, therefore it is necessary that it should be
denied to the drones even to generate another kind than themselves. This is just what we find happening, for
though the drones are themselves generated, they generate nothing else, but the process reaches its limit in the
third stage. And so beautifully is this arranged by Nature that the three kinds always continue in existence and
none of them fails, though they do not all generate.

Another fact is also natural, that in fine seasons much honey is collected and many drones are produced but in
rainy reasons a large brood of ordinary bees. For the wet causes more residual matter to be formed in the
bodies of the leaders, the fine weather in that of the bees, for being smaller in size they need the fine weather
more than the kings do. It is right also that the kings, being as it were made with a view to producing young,
should remain within, freed from the labour of procuring necessaries, and also that they should be of a
considerable size, their bodies being, as it were, constituted with a view to bearing young, and that the drones
should be idle as having no weapon to fight for the food and because of the slowness of their bodies. But the
bees are intermediate in size between the two other kinds, for this is useful for their work, and they are
workers as having to support not only their young but also their fathers. And it agrees with our views that the
bees attend upon their kings because they are their offspring (for if nothing of the sort had been the case the
facts about their leadership would be unreasonable), and that, while they suffer the kings to do no work as
being their parents, they punish the drones as their children, for it is nobler to punish one's children and those
who have no work to perform. The fact that the leaders, being few, generate the bees in large numbers seems
to be similar to what obtains in the generation of lions, which at first produce five, afterwards a smaller
number each time at last one and thereafter none. So the leaders at first produce a number of workers,
afterwards a few of their own kind; thus the brood of the latter is smaller in number than that of the former,
but where Nature has taken away from them in number she has made it up again in size.

Such appears to be the truth about the generation of bees, judging from theory and from what are believed to
be the facts about them; the facts, however, have not yet been sufficiently grasped; if ever they are, then
credit must be given rather to observation than to theories, and to theories only if what they affirm agrees
with the observed facts.

A further indication that bees are produced without copulation is the fact that the brood appears small in the
cells of the comb, whereas, whenever insects are generated by copulation, the parents remain united for a
long time but produce quickly something of the nature of a scolex and of a considerable size.

Concerning the generation of animals akin to them, as hornets and wasps, the facts in all cases are similar to a
certain extent, but are devoid of the extraordinary features which characterize bees; this we should expect, for
they have nothing divine about them as the bees have. For the so-called 'mothers' generate the young and
mould the first part of the combs, but they generate by copulation with one another, for their union has often
been observed. As for all the differences of each of these kind from one another and from bees, they must be
investigated with the aid of the illustrations to the Enquiries.

Having spoken of the generation of all insects, we must now speak of the testacea. Here also the facts of
generation are partly like and partly unlike those in the other classes. And this is what might be expected. For
compared with animals they resemble plants, compared with plants they resemble animals, so that in a sense
they appear to come into being from semen, but in another sense not so, and in one way they are
spontaneously generated but in another from their own kind, or some of them in the latter way, others in the
former. Because their nature answers to that of plants, therefore few or no kinds of testacea come into being

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on land, e.g. the snails and any others, few as they are, that resemble them; but in the sea and similar waters
there are many of all kinds of forms. But the class of plants has but few and one may say practically no
representatives in the sea and such places, all such growing on the land. For plants and testacea are
analogous; and in proportion as liquid has more quickening power than solid, water than earth, so much does
the nature of testacea differ from that of plants, since the object of testacea is to be in such a relation to water
as plants are to earth, as if plants were, so to say, land-oysters, oysters water-plants.

For such a reason also the testacea in the water vary more in form than those on the land. For the nature of
liquid is more plastic than that of earth and yet not much less material, and this is especially true of the
inhabitants of the sea, for fresh water, though sweet and nutritious, is cold and less material. Wherefore
animals having no blood and not of a hot nature are not produced in lakes nor in the fresher among brackish
waters, but only exceptionally, but it is in estuaries and at the mouths of rivers that they come into being, as
testacea and cephalopoda and Crustacea, all these being bloodless and of a cold nature. For they seek at the
same time the warmth of the sun and food; now the sea is not only water but much more material than fresh
water and hot in its nature; it has a share in all the parts of the universe, water and air and earth, so that it also
has a share in all living things which are produced in connexion with each of these elements. Plants may be
assigned to land, the aquatic animals to water, the land animals to air, but variations of quantity and distance
make a great and wonderful difference. The fourth class must not be sought in these regions, though there
certainly ought to be some animal corresponding to the element of fire, for this is counted in as the fourth of
the elementary bodies. But the form which fire assumes never appears to be peculiar to it, but it always exists
in some other of the elements, for that which is ignited appears to be either air or smoke or earth. Such a kind
of animal must be sought in the moon, for this appears to participate in the element removed in the third
degree from earth. The discussion of these things however belongs to another subject.

To return to testacea, some of them are formed spontaneously, some emit a sort of generative substance from
themselves, but these also often come into being from a spontaneous formation. To understand this we must
grasp the different methods of generation in plants; some of these are produced from seed, some from slips,
planted out, some by budding off alongside, as the class of onions. In the last way produced mussels, for
smaller ones are always growing off alongside the original, but the whelks, the purple-fish, and those which
are said to 'spawn' emit masses of a liquid slime as if originated by something of a seminal nature. We must
not, however, consider that anything of the sort is real semen, but that these creatures participate in the
resemblance to plants in the manner stated above. Hence when once one such creature has been produced,
then is produced a number of them. For all these creatures are liable to be even spontaneously generated, and
so to be formed still more plentifully in proportion if some are already existing. For it is natural that each
should have some superfluous residue attached to it from the original, and from this buds off each of the
creatures growing alongside of it. Again, since the nutriment and its residue possess a like power, it is likely
that the product of those testacea which 'spawn' should resemble the original formation, and so it is natural
that a new animal of the same kind should come into being from this also.

All those which do not bud off or 'spawn' are spontaneously generated. Now all things formed in this way,
whether in earth or water, manifestly come into being in connexion with putrefaction and an admixture of
rain-water. For as the sweet is separated off into the matter which is forming, the residue of the mixture takes
such a form. Nothing comes into being by putrefying, but by concocting; putrefaction and the thing putrefied
is only a residue of that which is concocted. For nothing comes into being out of the whole of anything, any
more than in the products of art; if it did art would have nothing to do, but as it is in the one case art removes
the useless material, in the other Nature does so. Animals and plants come into being in earth and in liquid
because there is water in earth, and air in water, and in all air is vital heat so that in a sense all things are full
of soul. Therefore living things form quickly whenever this air and vital heat are enclosed in anything. When
they are so enclosed, the corporeal liquids being heated, there arises as it were a frothy bubble. Whether what
is forming is to be more or less honourable in kind depends on the embracing of the psychical principle; this
again depends on the medium in which the generation takes place and the material which is included. Now in

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the sea the earthy matter is present in large quantities, and consequently the testaceous animals are formed
from a concretion of this kind, the earthy matter hardening round them and solidifying in the same manner as
bones and horns (for these cannot be melted by fire), and the matter (or body) which contains the life being
included within it.

The class of snails is the only class of such creatures that has been seen uniting, but it has never yet been
sufficiently observed whether their generation is the result of the union or not.

It may be asked, if we wish to follow the right line of investigation, what it is in such animals the formation
of which corresponds to the material principle. For in the females this is a residual secretion of the animal,
potentially such as that from which it came, by imparting motion to which the principle derived from the
male perfects the animal. But here what must be said to correspond to this, and whence comes or what is the
moving principle which corresponds to the male? We must understand that even in animals which generate it
is from the incoming nourishment that the heat in the animal makes the residue, the beginning of the
conception, by secretion and concoction. The like is the case also in plants, except that in these (and also in
some animals) there is no further need of the male principle, because they have it mingled with the female
principle within themselves, whereas the residual secretion in most animals does need it. The nourishment
again of some is earth and water, of others the more complicated combinations of these, so that what the heat
in animals produces from their nutriment, this does the heat of the warm season in the environment put
together and combine by concoction out of the sea-water on the earth. And the portion of the psychical
principle which is either included along with it or separated off in the air makes an embryo and puts motion
into it. Now in plants which are spontaneously generated the method of formation is uniform; they arise from
a part of something, and while some of it is the starting-point of the plant, some is the first nourishment of
the young shoots.... Other animals are produced in the form of a scolex, not only those bloodless animals
which are not generated from parents but even some sanguinea, as a kind of mullet and some other river
fishes and also the eel kind. For all of these, though they have but little blood by nature, are nevertheless
sanguinea, and have a heart with blood in it as the origin of the parts; and the so-called 'entrails of earth', in
which comes into being the body of the eel, have the nature of a scolex.

Hence one might suppose, in connexion with the origin of men and quadrupeds, that, if ever they were really
'earth-born' as some say, they came into being in one of two ways; that either it was by the formation of a
scolex at first or else it was out of eggs. For either they must have had in themselves the nutriment for growth
(and such a conception is a scolex) or they must have got it from elsewhere, and that either from the mother
or from part of the conception. If then the former is impossible (I mean that nourishment should flow to them
from the earth as it does in animals from the mother), then they must have got it from some part of the
conception, and such generation we say is from an egg.

It is plain then that, if there really was any such beginning of the generation of all animals, it is reasonable to
suppose to have been one of these two, scolex or egg. But it is less reasonable to suppose that it was from
eggs, for we do not see such generation occurring with any animal, but we do see the other both in the
sanguinea above mentioned and in the bloodless animals. Such are some of the insects and such are the
testacea which we are discussing; for they do not develop out of a part of something (as do animals from
eggs), and they grow like a scolex. For the scolex grows towards the upper part and the first principle, since
in the lower part is the nourishment for the upper. And this resembles the development of animals from eggs,
except that these latter consume the whole egg, whereas in the scolex, when the upper part has grown by
taking up into itself part of the substance in the lower part, the lower part is then differentiated out of the rest.
The reason is that in later life also the nourishment is absorbed by all animals in the part below the
hypozoma.

That the scolex grows in this way is plain in the case of bees and the like, for at first the lower part is large in
them and the upper is smaller. The details of growth in the testacea are similar. This is plain in the whorls of

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ON THE GENERATION OF ANIMALS

the turbinata, for always as the animal grows the whorls become larger towards the front and what is called
the head of the creature.

We have now pretty well described the manner of the development of these and the other spontaneously
generated animals. That all the testacea are formed spontaneously is clear from such facts as these. They
come into being on the side of boats when the frothy mud putrefies. In many places where previously nothing
of the kind existed, the so-called limnostrea, a kind of oyster, have come into being when the spot turned
muddy through want of water; thus when a naval armament cast anchor at Rhodes a number of clay vessels
were thrown out into the sea, and after some time, when mud had collected round them, oysters used to be
found in them. Here is another proof that such animals do not emit any generative substance from
themselves; when certain Chians carried some live oysters over from Pyrrha in Lesbos and placed them in
narrow straits of the sea where tides clash, they became no more numerous as time passed, but increased
greatly in size. The so-called eggs contribute to generation but are only a condition, like fat in the sanguinea,
and therefore the oysters are savoury at these periods. A proof that this substance is not really eggs is the fact
that such 'eggs' are always found in some testacea, as in pinnae, whelks, and purple-fish; only they are
sometimes larger and sometimes smaller; in others as pectens, mussels, and the so-called limnostrea, they are
not always present but only in the spring; as the season advances they dwindle and at last disappear
altogether; the reason being that the spring is favourable to their being in good condition. In others again, as
the ascidians, nothing of the sort is visible. (The details concerning these last, and the places in which they
come into being, must be learnt from the Enquiry.)

Book IV

WE have thus spoken of the generation of animals both generally and separately in all the different classes.
But, since male and female are distinct in the most perfect of them, and since we say that the sexes are first
principles of all living things whether animals or plants, only in some of them the sexes are separated and in
others not, therefore we must speak first of the origin of the sexes in the latter. For while the animal is still
imperfect in its kind the distinction is already made between male and female.

It is disputed, however, whether the embryo is male or female, as the case may be, even before the distinction
is plain to our senses, and further whether it is thus differentiated within the mother or even earlier. It is said
by some, as by Anaxagoras and other of the physicists, that this antithesis exists from the beginning in the
germs or seeds; for the germ, they say, comes from the male while the female only provides the place in
which it is to be developed, and the male is from the right, the female from the left testis, and so also that the
male embryo is in the right of the uterus, the female in the left. Others, as Empedocles, say that the
differentiation takes place in the uterus; for he says that if the uterus is hot or cold what enters it becomes
male or female, the cause of the heat or cold being the flow of the catamenia, according as it is colder or
hotter, more 'antique' or more 'recent'. Democritus of Abdera also says that the differentiation of sex takes
place within the mother; that however it is not because of heat and cold that one embryo becomes female and
another male, but that it depends on the question which parent it is whose semen prevails,- not the whole of
the semen, but that which has come from the part by which male and female differ from one another. This is a
better theory, for certainly Empedocles has made a rather light-hearted assumption in thinking that the
difference between them is due only to cold and heat, when he saw that there was a great difference in the
whole of the sexual parts, the difference in fact between the male pudenda and the uterus. For suppose two
animals already moulded in embryo, the one having all the parts of the female, the other those of the male;
suppose them then to be put into the uterus as into an oven, the former when the oven is hot, the latter when it
is cold; then on the view of Empedocles that which has no uterus will be female and that which has will be
male. But this is impossible. Thus the theory of Democritus would be the better of the two, at least as far as

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this goes, for he seeks for the origin of this difference and tries to set it forth; whether he does so well or not
is another question.

Again, if heat and cold were the cause of the difference of the parts, this ought to have been stated by those
who maintain the view of Empedocles; for to explain the origin of male and female is practically the same
thing as to explain this, which is the manifest difference between them. And it is no small matter, starting
from temperature as a principle, to collect the cause of the origin of these parts, as if it were a necessary
consequence for this part which they call the uterus to be formed in the embryo under the influence of cold
but not under that of heat. The same applies also to the parts which serve for intercourse, since these also
differ in the way stated previously.

Moreover male and female twins are often found together in the same part of the uterus; this we have
observed sufficiently by dissection in all the vivipara, both land animals and fish. Now if Empedocles had not
seen this it was only natural for him to fall into error in assigning this cause of his; but if he had seen it it is
strange that he should still think the heat or cold of the uterus to be the cause, since on his theory both these
twins would have become either male or female, but as it is we do not see this to be the fact.

Again he says that the parts of the embryo are 'sundered', some being in the male and some in the female
parent, which is why they desire intercourse with one another. If so it is necessary that the sexual parts like
the rest should be separated from one another, already existing as masses of a certain size, and that they
should come into being in the embryo on account of uniting with one another, not on account of cooling or
heating of the semen. But perhaps it would take too long to discuss thoroughly such a cause as this which is
stated by Empedocles, for its whole character seems to be fanciful. If, however, the facts about semen are
such as we have actually stated, if it does not come from the whole of the body of the male parent and if the
secretion of the male does not give any material at all to the embryo, then we must make a stand against both
Empedocles and Democritus and any one else who argues on the same lines. For then it is not possible that
the body of the embryo should exist 'sundered', part in the female parent and part in the male, as Empedocles
says in the words: 'But the nature of the limbs hath been sundered, part in the man's...'; nor yet that a whole
embryo is drawn off from each parent and the combination of the two becomes male or female according as
one part prevails over another.

And, to take a more general view, though it is better to say that the one part makes the embryo female by
prevailing through some superiority than to assign nothing but heat as the cause without any reflection, yet,
as the form of the pudendum also varies along with the uterus from that of the father, we need an explanation
of the fact that both these parts go along with each other. If it is because they are near each other, then each of
the other parts also ought to go with them, for one of the prevailing parts is always near another part where
the struggle is not yet decided; thus the offspring would be not only female or male but also like its mother or
father respectively in all other details.

Besides, it is absurd to suppose that these parts should come into being as something isolated, without the
body as a whole having changed along with them. Take first and foremost the blood-vessels, round which
the whole mass of the flesh lies as round a framework. It is not reasonable that these should become of a
certain quality because of the uterus, but rather that the uterus should do so on account of them. For though it
is true that each is a receptacle of blood of some kind, still the system of the vessels is prior to the other; the
moving principle must needs always be prior to that which it moves, and it is because it is itself of a certain
quality that it is the cause of the development. The difference, then, of these parts as compared with each
other in the two sexes is only a concomitant result; not this but something else must be held to be the first
principle and the cause of the development of an embryo as male or female; this is so even if no semen is
secreted by either male or female, but the embryo is formed in any way you please.

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The same argument as that with which we meet Empedocles and Democritus will serve against those who say
that the male comes from the right and the female from the left. If the male contributes no material to the
embryo, there can be nothing in this view. If, as they say, he does contribute something of the sort, we must
confront them in the same way as we did the theory of Empedocles, which accounts for the difference
between male and female by the heat and cold of the uterus. They make the same mistake as he does, when
they account for the difference by their 'right and left', though they see that the sexes differ actually by the
whole of the sexual parts; for what reason then is the body of the uterus to exist in those embryos which come
from the left and not in those from the right? For if an embryo have come from the left but has not acquired
this part, it will be a female without a uterus, and so too there is nothing to stop another from being a male
with a uterus! Besides as has been said before, a female embryo has been observed in the right part of the
uterus, a male in the left, or again both at once in the same part, and this not only once but several times.

Some again, persuaded of the truth of a view resembling that of these philosophers, say that if a man
copulates with the right or left testis tied up the result is male or female offspring respectively; so at least
Leophanes asserted. And some say that the same happens in the case of those who have one or other testis
excised, not speaking truth but vaticinating what will happen from probabilities and jumping at the
conclusion that it is so before seeing that it proves to be so. Moreover, they know not that these parts of
animals contribute nothing to the production of one sex rather than the other; a proof of this is that many
animals in which the distinction of sex exists, and which produce both male and female offspring,
nevertheless have no testes, as the footless animals; I mean the classes of fish and of serpents.

To suppose, then, either that heat and cold are the causes of male and female, or that the different sexes come
from the right and left, is not altogether unreasonable in itself; for the right of the body is hotter than the left,
and the concocted semen is hotter than the unconcocted; again, the thickened is concocted, and the more
thickened is more fertile. Yet to put it in this way is to seek for the cause from too remote a starting-point;
we must draw near the immediate causes in so far as it is possible for us.

We have, then, previously spoken elsewhere of both the body as a whole and its parts, explaining what each
part is and for what reason it exists. But (1) the male and female are distinguished by a certain capacity and
incapacity. (For the male is that which can concoct the blood into semen and which can form and secrete and
discharge a semen carrying with it the principle of form- by 'principle' I do not mean a material principle out
of which comes into being an offspring resembling the parent, but I mean the first moving cause, whether it
have power to act as such in the thing itself or in something else- but the female is that which receives
semen, indeed, but cannot form it for itself or secrete or discharge it.) And (2) all concoction works by means
of heat. Therefore the males of animals must needs be hotter than the females. For it is by reason of cold and
incapacity that the female is more abundant in blood in certain parts of her anatomy, and this abundance is an
evidence of the exact opposite of what some suppose, thinking that the female is hotter than the male for this
reason, i.e. the discharge of the catamenia. It is true that blood is hot, and that which has more of it is hotter
than that which has less. But they assume that this discharge occurs through excess of blood and of heat, as if
it could be taken for granted that all blood is equally blood if only it be liquid and sanguineous in colour, and
as if it might not become less in quantity but purer in quality in those who assimilate nourishment properly.
In fact they look upon this residual discharge in the same light as that of the intestines, when they think that a
greater amount of it is a sign of a hotter nature, whereas the truth is just the opposite. For consider the
production of fruit; the nutriment in its first stage is abundant, but the useful product derived from it is small,
indeed the final result is nothing at all compared to the quantity in the first stage. So is it with the body; the
various parts receive and work up the nutriment, from the whole of which the final result is quite small. This
is blood in some animals, in some its analogue. Now since (1) the one sex is able and the other is unable to
reduce the residual secretion to a pure form, and (2) every capacity or power in an organism has a certain
corresponding organ, whether the faculty produces the desired results in a lower degree or in a higher degree,
and the two sexes correspond in this manner (the terms 'able' and 'unable' being used in more senses than
one)- therefore it is necessary that both female and male should have organs. Accordingly the one has the

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uterus, the other the male organs.

Again, Nature gives both the faculty and the organ to each individual at the same time, for it is better so.
Hence each region comes into being along with the secretions and the faculties, as e.g. the faculty of sight is
not perfected without the eye, nor the eye without the faculty of sight; and so too the intestine and bladder
come into being along with the faculty of forming the excreta. And since that from which an organ comes
into being and that by which it is increased are the same (i.e. the nutriment), each of the parts will be made
out of such a material and such residual matter as it is able to receive. In the second place, again, it is formed,
as we say, in a certain sense, out of its opposite. Thirdly, we must understand besides this that, if it is true that
when a thing perishes it becomes the opposite of what it was, it is necessary also that what is not under the
sway of that which made it must change into its opposite. After these premisses it will perhaps be now clearer
for what reason one embryo becomes female and another male. For when the first principle does not bear
sway and cannot concoct the nourishment through lack of heat nor bring it into its proper form, but is
defeated in this respect, then must needs the material which it works on change into its opposite. Now the
female is opposite to the male, and that in so far as the one is female and the other male. And since it differs
in its faculty, its organ also is different, so that the embryo changes into this state. And as one part of
first-rate importance changes, the whole system of the animal differs greatly in form along with it. This may
be seen in the case of eunuchs, who, though mutilated in one part alone, depart so much from their original
appearance and approximate closely to the female form. The reason of this is that some of the parts are
principles, and when a principle is moved or affected needs must many of the parts that go along with it
change with it.

If then (1) the male quality or essence is a principle and a cause, and (2) the male is such in virtue of a certain
capacity and the female is such in virtue of an incapacity, and (3) the essence or definition of the capacity and
of the incapacity is ability or inability to concoct the nourishment in its ultimate stage, this being called blood
in the sanguinea and the analogue of blood in the other animals, and (4) the cause of this capacity is in the
first principle and in the part which contains the principle of natural heat- therefore a heart must be formed in
the sanguinea (and the resulting animal will be either male or female), and in the other kinds which possess
the sexes must be formed that which is analogous to the heart.

This, then, is the first principle and cause of male and female, and this is the part of the body in which it
resides. But the animal becomes definitely female or male by the time when it possesses also the parts by
which the female differs from the male, for it is not in virtue of any part you please that it is male or female,
any more than it is able to see or hear by possessing any part you please.

To recapitulate, we say that the semen, which is the foundation of the embryo, is the ultimate secretion of the
nutriment. By ultimate I mean that which is carried to every part of the body, and this is also the reason why
the offspring is like the parent. For it makes no difference whether we say that the semen comes from all the
parts or goes to all of them, but the latter is the better. But the semen of the male differs from the
corresponding secretion of the female in that it contains a principle within itself of such a kind as to set up
movements also in the embryo and to concoct thoroughly the ultimate nourishment, whereas the secretion of
the female contains material alone. If, then, the male element prevails it draws the female element into itself,
but if it is prevailed over it changes into the opposite or is destroyed. But the female is opposite to the male,
and is female because of its inability to concoct and of the coldness of the sanguineous nutriment. And Nature
assigns to each of the secretions the part fitted to receive it. But the semen is a secretion, and this in the hotter
animals with blood, i.e. the males, is moderate in quantity, wherefore the recipient parts of this secretion in
males are only passages. But the females, owing to inability to concoct, have a great quantity of blood, for it
cannot be worked up into semen. Therefore they must also have a part to receive this, and this part must be
unlike the passages of the male and of a considerable size. This is why the uterus is of such a nature, this
being the part by which the female differs from the male.

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We have thus stated for what reason the one becomes female and the other male. Observed facts confirm
what we have said. For more females are produced by the young and by those verging on old age than by
those in the prime of life; in the former the vital heat is not yet perfect, in the latter it is failing. And those of a
moister and more feminine state of body are more wont to beget females, and a liquid semen causes this more
than a thicker; now all these characteristics come of deficiency in natural heat.

Again, more males are born if copulation takes place when north than when south winds are blowing. For in
the latter case the animals produce more secretion, and too much secretion is harder to concoct; hence the
semen of the males is more liquid, and so is the discharge of the catamenia.

Also the fact that the catamenia occur in the course of nature rather when the month is waning is due to the
same causes. For this time of the month is colder and moister because of the waning and failure of the moon;
as the sun makes winter and summer in the year as a whole, so does the moon in the month. This is not due to
the turning of the moon, but it grows warmer as the light increases and colder as it wanes.

The shepherds also say that it not only makes a difference in the production of males and females if
copulation takes place during northern or southerly winds, but even if the animals while copulating look
towards the south or north; so small a thing will sometimes turn the scale and cause cold or heat, and these
again influence generation.

The male and female, then, are distinguished generally, as compared with one another in connexion with the
production of male and female offspring, for the causes stated. However, they also need a certain
correspondence with one another to produce at all, for all things that come into being as products of art or of
Nature exist in virtue of a certain ratio. Now if the hot preponderates too much it dries up the liquid; if it is
very deficient it does not solidify it; for the artistic or natural product we need the due mean between the
extremes. Otherwise it will be as in cooking; too much fire burns the meat, too little does not cook it, and in
either case the process is a failure. So also there is need of due proportion in the mixture of the male and
female elements. And for this cause it often happens to many of both sexes that they do not generate with one
another, but if divorced and remarried to others do generate; and these oppositions show themselves
sometimes in youth, sometimes in advanced age, alike as concerns fertility or infertility, and as concerns
generation of male or female offspring.

One country also differs from another in these respects, and one water from another, for the same reasons.
For the nourishment and the medical condition of the body are of such or such a kind because of the
tempering of the surrounding air and of the food entering the body, especially the water; for men consume
more of this than of anything else, and this enters as nourishment into all food, even solids. Hence hard
waters cause infertility, and cold waters the birth of females.

The same causes must be held responsible for the following groups of facts. (1) Some children resemble their
parents, while others do not; some being like the father and others like the mother, both in the body as a
whole and in each part, male and female offspring resembling father and mother respectively rather than the
other way about. (2) They resemble their parents more than remoter ancestors, and resemble those ancestors
more than any chance individual. (3) Some, though resembling none of their relations, yet do at any rate
resemble a human being, but others are not even like a human being but a monstrosity. For even he who does
not resemble his parents is already in a certain sense a monstrosity; for in these cases Nature has in a way
departed from the type. The first departure indeed is that the offspring should become female instead of male;

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ON THE GENERATION OF ANIMALS

this, however, is a natural necessity. (For the class of animals divided into sexes must be preserved, and as it
is possible for the male sometimes not to prevail over the female in the mixture of the two elements, either
through youth or age or some other such cause, it is necessary that animals should produce female young).
And the monstrosity, though not necessary in regard of a final cause and an end, yet is necessary accidentally.
As for the origin of it, we must look at it in this way. If the generative secretion in the catamenia is properly
concocted, the movement imparted by the male will make the form of the embryo in the likeness of itself.
(Whether we say that it is the semen or this movement that makes each of the parts grow, makes no
difference; nor again whether we say that it 'makes them grow' or 'forms them from the beginning', for the
formula of the movement is the same in either case.) Thus if this movement prevail, it will make the embryo
male and not female, like the father and not like the mother; if it prevail not, the embryo is deficient in that
faculty in which it has not prevailed. By 'each faculty' I mean this. That which generates is not only male but
also a particular male, e.g. Coriscus or Socrates, and it is not only Coriscus but also a man. In this way some
of the characteristics of the father are more near to him, others more remote from him considered simply as a
parent and not in reference to his accidental qualities (as for instance if the parent is a scholar or the
neighbour of some particular person). Now the peculiar and individual has always more force in generation
than the more general and wider characteristics. Coriscus is both a man and an animal, but his manhood is
nearer to his individual existence than is his animalhood. In generation both the individual and the class are
operative, but the individual is the more so of the two, for this is the only true existence. And the offspring is
produced indeed of a certain quality, but also as an individual, and this latter is the true existence. Therefore it
is from the forces of all such existences that the efficient movements come which exist in the semen;
potentially from remoter ancestors but in a higher degree and more nearly from the individual (and by the
individual I mean e.g. Coriscus or Socrates). Now since everything changes not into anything haphazard but
into its opposite, therefore also that which is not prevailed over in generation must change and become the
opposite, in respect of that particular force in which the paternal and efficient or moving element has not
prevailed. If then it has not prevailed in so far as it is male, the offspring becomes female; if in so far as it is
Coriscus or Socrates, the offspring does not resemble the father but the mother. For as 'father' and 'mother' are
opposed as general terms, so also the individual father is opposed to the individual mother. The like applies
also to the forces that come next in order, for the offspring always changes rather into the likeness of the
nearer ancestor than the more remote, both in the paternal and in the maternal line.

Some of the movements exist in the semen actually, others potentially; actually, those of the father and the
general type, as man and animal; potentially those of the female and the remoter ancestors. Thus the male and
efficient principle, if it lose its own nature, changes to its opposites, but the movements which form the
embryo change into those nearly connected with them; for instance, if the movement of the male parent be
resolved, it changes by a very slight difference into that of his father, and in the next instance into that of his
grandfather; and in this way not only in the male but also in the female line the movement of the female
parent changes into that of her mother, and, if not into this, then into that of her grandmother; and similarly
also with the more remote ancestors.

Naturally then it is most likely that the characteristics of 'male' and of the individual father will go together,
whether they prevail or are prevailed over. For the difference between them is small so that there is no
difficulty in both concurring, for Socrates is an individual man with certain characters. Hence for the most
part the male offspring resemble the father, and the female the mother. For in the latter case the loss of both
characters takes place at once, and the change is into the two opposites; now is opposed to male, and the
individual mother to the individual father.

But if the movement coming from the male principle prevails while that coming from the individual Socrates
does not, or vice versa, then the result is that male children are produced resembling the mother and female
children resembling the father.

ON THE GENERATION OF ANIMALS

If again the movements be resolved, if the male character remain but the movement coming from the
individual Socrates be resolved into that of the father of Socrates, the result will be a male child resembling
its grandfather or some other of its more remote ancestors in the male line on the same principle. If the male
principle be prevailed over, the child will be female and resembling most probably its mother, but, if the
movement coming from the mother also be resolved, it will resemble its mother's mother or the resemblance
will be to some other of its more remote ancestors in the female line on the same principle.

The same applies also to the separate parts, for often some of these take after the father, and others after the
mother, and yet others after some of the remoter ancestors. For, as has been often said already, some of the
movements which form the parts exist in the semen actually and others potentially. We must grasp certain
fundamental general principles, not only that just mentioned (that some of the movements exist potentially
and others actually), but also two others, that if a character be prevailed over it changes into its opposite, and,
if it be resolved, is resolved into the movement next allied to it- if less, into that which is near, if more, into
that which is further removed. Finally, the movements are so confused together that there is no resemblance
to any of the family or kindred, but the only character that remains is that common to the race, i.e. it is a
human being. The reason of this is that this is closely knit up with the individual characteristics; 'human
being' is the general term, while Socrates, the father, and the mother, whoever she may be, are individuals.

The reason why the movements are resolved is this. The agent is itself acted upon by that on which it acts;
thus that which cuts is blunted by that which is cut by it, that which heats is cooled by that which is heated by
it, and in general the moving or efficient cause (except in the case of the first cause of all) does itself receive
some motion in return; e.g. what pushes is itself in a way pushed again and what crushes is itself crushed
again. Sometimes it is altogether more acted upon than is the thing on which it acts, so that what is heating or
cooling something else is itself cooled or heated; sometimes having produced no effect, sometimes less than
it has itself received. (This question has been treated in the special discussion of action and reaction, where it
is laid down in what classes of things action and reaction exist.) Now that which is acted on escapes and is
not mastered by the semen, either through deficiency of power in the concocting and moving agent or
because what should be concocted and formed into distinct parts is too cold and in too great quantity. Thus
the moving agent, mastering it in one part but not in another, makes the embryo in formation to be multiform,
as happens with athletes because they eat so much. For owing to the quantity of their food their nature is not
able to master it all, so as to increase and arrange their form symmetrically; therefore their limbs develop
irregularly, sometimes indeed almost so much that no one of them resembles what it was before. Similar to
this is also the disease known as satyrism, in which the face appears like that of a satyr owing to a quantity of
unconcocted humour or wind being diverted into parts of the face.

We have thus discussed the cause of all these phenomena, (1) female and male offspring are produced, (2)
why some are similar to their parents, female to female and male to male, and others the other way about,
females being similar to the father and males to the mother, and in general why some are like their ancestors
while others are like none of them, and all this as concerns both the body as a whole and each of the parts
separately. Different accounts, however, have been given of these phenomena by some of the
nature-philosophers; I mean why children are like or unlike their parents. They give two versions of the
reason. Some say that the child is more like that parent of the two from whom comes more semen, this
applying equally both to the body as a whole and to the separate parts, on the assumption that semen comes
from each part of both parents; if an equal part comes from each, then, they say, the child is like neither. But
if this is false, if semen does not come off from the whole body of the parents, it is clear that the reason
assigned cannot be the cause of likeness and unlikeness. Moreover, they are hard put to it to explain how it is
that a female child can be like the father and a male like the mother. For (1) those who assign the same cause
of sex as Empedocles or Democritus say what is on other grounds impossible, and (2) those who say that it is
determined by the greater or smaller amount of semen coming the male or female parent, and that this is why
one child is male and another female, cannot show how the female is to resemble the father and the male the
mother, for it is impossible that more should come from both at once. Again, for what reason is a child

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generally like its ancestors, even the more remote? None of the semen has come from them at any rate.

But those who account for the similarity in the manner which remains to be discussed, explain this point
better, as well as the others. For there are some who say that the semen, though one, is as it were a common
mixture (panspermia) of many elements; just as, if one should mix many juices in one liquid and then take
some from it, it would be possible to take, not an equal quantity always from each juice, but sometimes more
of one and sometimes more of another, sometimes some of one and none at all of another, so they say it is
with the generative fluid, which is a mixture of many elements, for the offspring resembles that parent from
which it has derived most. Though this theory is obscure and in many ways fictitious, it aims at what is better
expressed by saying that what is called 'panspermia' exists potentially, not actually; it cannot exist actually,
but it can do so potentially. Also, if we assign only one sort of cause, it is not easy to explain all the
phenomena, (1) the distinction of sex, (2) why the female is often like the father and the male like the mother,
and again (3) the resemblance to remoter ancestors, and further (4) the reason why the offspring is sometimes
unlike any of these but still a human being, but sometimes, (5) proceeding further on these lines, appears
finally to be not even a human being but only some kind of animal, what is called a monstrosity.

For, following what has been said, it remains to give the reason for such monsters. If the movements imparted
by the semen are resolved and the material contributed by the mother is not controlled by them, at last there
remains the most general substratum, that is to say the animal. Then people say that the child has the head of
a ram or a bull, and so on with other animals, as that a calf has the head of a child or a sheep that of an ox. All
these monsters result from the causes stated above, but they are none of the things they are said to be; there is
only some similarity, such as may arise even where there is no defect of growth. Hence often jesters compare
some one who is not beautiful to a 'goat breathing fire', or again to a 'ram butting', and a certain
physiognomist reduced all faces to those of two or three animals, and his arguments often prevailed on
people.

That, however, it is impossible for such a monstrosity to come into existence- I mean one animal in another-
is shown by the great difference in the period of gestation between man, sheep, dog, and ox, it being
impossible for each to be developed except in its proper time.

This is the description of some of the monsters talked about; others are such because certain parts of their
form are multiplied so that they are born with many feet or many heads.

The account of the cause of monstrosities is very close and similar in a way to that of the cause of animals
being born defective in any part, for monstrosity is also a kind of deficiency.

Democritus said that monstrosities arose because two emissions of seminal fluid met together, the one
succeeding the other at an interval of time; that the later entering into the uterus reinforced the earlier so that
the parts of the embryo grow together and get confused with one another. But in birds, he says, since
copulation takes place quickly, both the eggs and their colour always cross one another. But if it is the fact, as
it manifestly is, that several young are produced from one emission of semen and a single act of intercourse,
it is better not to desert the short road to go a long way about, for in such cases it is absolutely necessary that
this should occur when the semen is not separated but all enters the female at once.

If, then, we must attribute the cause to the semen of the male, this will be the way we shall have to state it,
but we must rather by all means suppose that the cause lies in the material contributed by the female and in
the embryo as it is forming. Hence also such monstrosities appear very rarely in animals producing only one
young one, more frequently in those producing many, most of all in birds and among birds in the common

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fowl. For this bird produces many young, not only because it lays often like the pigeon family, but also
because it has many embryos at once and copulates all the year round. Therefore it produces many double
eggs, for the embryos grow together because they are near one another, as often happens with many fruits. In
such double eggs, when the yolks are separated by the membrane, two separate chickens are produced with
nothing abnormal about them; when the yolks are continuous, with no division between them, the chickens
produced are monstrous, having one body and head but four legs and four wings; this is because the upper
parts are formed earlier from the white, their nourishment being drawn from the yolk, whereas the lower part
comes into being later and its nourishment is one and indivisible.

A snake has also been observed with two heads for the same reason, this class also being oviparous and
producing many young. Monstrosities, however, are rarer among them owing to the shape of the uterus, for
by reason of its length the numerous eggs are set in a line.

Nothing of the kind occurs with bees and wasps, because their brood is in separate cells. But in the fowl the
opposite is the case, whereby it is plain that we must hold the cause of such phenomena to lie in the material.
So, too, monstrosities are commoner in other animals if they produce many young. Hence they are less
common in man, for he produces for the most part only one young one and that perfect; even in man
monstrosities occur more often in regions where the women give birth to more than one at a time, as in
Egypt. And they are commoner in sheep and goats, since they produce more young. Still more does this apply
to the fissipeds, for such animals produce many young and imperfect, as the dog, the young of these creatures
being generally blind. Why this happens and why they produce many young must be stated later, but in them
Nature has made an advance towards the production of monstrosities in that what they generate, being
imperfect, is so far unlike the parent; now monstrosities also belong to the class of things unlike the parent.
Therefore this accident also often invades animals of such a nature. So, too, it is in these that the so-called
'metachoera' are most frequent, and the condition of these also is in a way monstrous, since both deficiency
and excess are monstrous. For the monstrosity belongs to the class of things contrary to Nature, not any and
every kind of Nature, but Nature in her usual operations; nothing can happen contrary to Nature considered as
eternal and necessary, but we speak of things being contrary to her in those cases where things generally
happen in a certain way but may also happen in another way. In fact, even in the case of monstrosities,
whenever things occur contrary indeed to the established order but still always in a certain way and not at
random, the result seems to be less of a monstrosity because even that which is contrary to Nature is in a
certain sense according to Nature, whenever, that is, the formal nature has not mastered the material nature.
Therefore they do not call such things monstrosities any more than in the other cases where a phenomenon
occurs habitually, as in fruits; for instance, there is a vine which some call 'capneos'; if this bear black grapes
they do not judge it a monstrosity because it is in the habit of doing this very often. The reason is that it is in
its nature intermediate between white and black; thus the change is not a violent one nor, so to say, contrary
to Nature; at least, is it not a change into another nature. But in animals producing many young not only do
the same phenomena occur, but also the numerous embryos hinder one another from becoming perfect and
interfere with the generative motions imparted by the semen.

A difficulty may be raised concerning (1) the production of many young and the multiplication of the parts in
a single young one, and (2) the production of few young or only one and the deficiency of the parts.
Sometimes animals are born with too many toes, sometimes with one alone, and so on with the other parts,
for they may be multiplied or they may be absent. Again, they may have the generative parts doubled, the one
being male, the other female; this is known in men and especially in goats. For what are called 'tragaenae' are
such because they have both male and female generative parts; there is a case also of a goat being born with a
horn upon its leg. Changes and deficiencies are found also in the internal parts, animals either not possessing
some at all, or possessing them in a rudimentary condition, or too numerous or in the wrong place. No
animal, indeed, has ever been born without a heart, but they are born without a spleen or with two spleens or
with one kidney; there is no case again of total absence of the liver, but there are cases of its being
incomplete. And all these phenomena have been seen in animals perfect and alive. Animals also which

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naturally have a gall-bladder are found without one; others are found to have more than one. Cases are
known, too, of the organs changing places, the liver being on the left, the spleen on the right. These
phenomena have been observed, as stated above, in animals whose growth is perfected; at the time of birth
great confusion of every kind has been found. Those deficiency which only depart a little from Nature
commonly live; not so those which depart further, when the unnatural condition is in the parts which are
sovereign over life.

The question then about all these cases is this. Are we to suppose that a single cause is responsible for the
production of a single young one and for the deficiency of the parts, and another but still a single cause for
the production of many young and the multiplication of parts, or not?

In the first place it seems only reasonable to wonder why some animals produce many young, others only
one. For it is the largest animals that produce one, e.g. the elephant, camel, horse, and the other solid-hoofed
ungulates; of these some are larger than all other animals, while the others are of a remarkable size. But the
dog, the wolf, and practically all the fissipeds, produce many, even the small members of the class, as the
mouse family. The cloven-footed animals again produce few, except the pig, which belongs to those that
produce many. This certainly seems surprising, for we should expect the large animals to be able to generate
more young and to secrete more semen. But precisely what we wonder at is the reason for not wondering; it is
just because of their size that they do not produce many young, for the nutriment is expended in such animals
upon increasing the body. But in the smaller animals Nature takes away from the size and adds the excess so
gained to the seminal secretion. Moreover, more semen must needs be used in generation by the larger
animal, and little by the smaller. Therefore many small ones may be produced together, but it is hard for
many large ones to be so, and to those intermediate in size Nature has assigned the intermediate number. We
have formerly given the reason why some animals are large, some smaller, and some between the two, and
speaking generally, with regard to the number of young produced, the solid-hoofed produce one, the
cloven-footed few, the many-toed many. (The reason of this is that, generally speaking, their sizes
correspond to this difference.) It is not so, however, in all cases; for it is the largeness and smallness of the
body that is cause of few or many young being born, not the fact that the kind of animal has one, two, or
many toes. A proof of this is that the elephant is the largest of animals and yet is many-toed, and the camel,
the next largest, is cloven-footed. And not only in animals that walk but also in those that fly or swim the
large ones produce few, the small many, for the same reason. In like manner also it is not the largest plants
that bear most fruit.

We have explained then why some animals naturally produce many young, some but few, and some only one;
in the difficulty now stated we may rather be surprised with reason at those which produce many, since such
animals are often seen to conceive from a single copulation. Whether the semen of the male contributes to the
material of the embryo by itself becoming a part of it and mixing with the semen of the female, or whether, as
we say, it does not act in this way but brings together and fashions the material within the female and the
generative secretion as the fig-juice does the liquid substance of milk, what is the reason why it does not
form a single animal of considerable size? For certainly in the parallel case the fig-juice is not separated if it
has to curdle a large quantity of milk, but the more the milk and the more the fig-juice put into it, so much
the greater is the curdled mass. Now it is no use to say that the several regions of the uterus attract the semen
and therefore more young than one are formed, because the regions are many and the cotyledons are more
than one. For two embryos are often formed in the same region of the uterus, and they may be seen lying in a
row in animals that produce many, when the uterus is filled with the embryos. (This is plain from the
dissections.) Rather the truth is this. As animals complete their growth there are certain limits to their size,
both upwards and downwards, beyond which they cannot go, but it is in the space between these limits that
they exceed or fall short of one another in size, and it is within these limits that one man (or any other animal)
is larger or smaller than another. So also the generative material from which each animal is formed is not
without a quantitative limit in both directions, nor can it be formed from any quantity you please. Whenever
then an animal, for the cause assigned, discharges more of the female secretion than is needed for beginning

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the existence of a single animal, it is not possible that only one should be formed out of all this, but a number
limited by the appropriate size in each case; nor will the semen of the male, or the power residing in the
semen, form anything either more or less than what is according to Nature. In like manner, if the male emits
more semen than is necessary, or more powers in different parts of the semen as it is divided, however much
it is it will not make anything greater; on the contrary it will dry up the material of the female and destroy it.
So fire also does not continue to make water hotter in proportion as it is itself increased, but there is a fixed
limit to the heat of which water is capable; if that is once reached and the fire is then increased, the water no
longer gets hotter but rather evaporates and at last disappears and is dried up. Now since it appears that the
secretion of the female and that from the male need to stand in some proportionate relation to one another (I
mean in animals of which the male emits semen), what happens in those that produce many young is this:
from the very first the semen emitted by the male has power, being divided, to form several embryos, and the
material contributed by the female is so much that several can be formed out of it. (The parallel of curdling
milk, which we spoke of before, is no longer in point here, for what is formed by the heat of the semen is not
only of a certain quantity but also of a certain quality, whereas with fig-juice and rennet quantity alone is
concerned.) This then is just the reason why in such animals the embryos formed are numerous and do not all
unite into one whole; it is because an embryo is not formed out of any quantity you please, but whether there
is too much or too little, in either case there will be no result, for there is a limit set alike to the power of the
heat which acts on the material and to the material so acted upon.

On the same principle many embryos are not formed, though the secretion is much, in the large animals
which produce only one young one, for in them also both the material and that which works upon it are of a
certain quantity. So then they do not secrete such material in too great quantity for the reason previously
stated, and what they do secrete is naturally just enough for one embryo alone to be formed from it. If ever
too much is secreted, then twins are born. Hence such cases seem to be more portentous, because they are
contrary to the general and customary rule.

Man belongs to all three classes, for he produces one only and sometimes many or few, though naturally he
almost always produces one. Because of the moisture and heat of his body he may produce many [for semen
is naturally fluid and hot], but because of his size he produces few or one. On account of this it results that in
man alone among animals the period of gestation is irregular; whereas the period is fixed in the rest, there are
several periods in man, for children are born at seven months and at ten months and at the times between, for
even those of eight months do live though less often than the rest. The reason may be gathered from what has
just been said, and the question has been discussed in the Problems. Let this explanation suffice for these
points.

The cause why the parts may be multiplied contrary to Nature is the same as the cause of the birth of twins.
For the reason exists already in the embryo, whenever it aggregates more material at any point of itself than is
required by the nature of the part. The result is then that either one of its parts is larger than the others, as a
finger or hand or foot or any of the other extremities or limbs; or again if the embryo is cleft there may come
into being more than one such part, as eddies do in rivers; as the water in these is carried along with a certain
motion, if it dash against anything two systems or eddies come into being out of one, each retaining the same
motion; the same thing happens also with the embryos. The abnormal parts generally are attached near those
they resemble, but sometimes at a distance because of the movement- taking place in the embryo, and
especially because of the excess of material returning to that place whence it was taken away while retaining
the form of that part whence it arose as a superfluity.

In certain cases we find a double set of generative organs [one male and the other female]. When such
duplication occurs the one is always functional but not the other, because it is always insufficiently supplied
with nourishment as being contrary to Nature; it is attached like a growth (for such growths also receive
nourishment though they are a later development than the body proper and contrary to Nature.) If the
formative power prevails, both are similar; if it is altogether vanquished, both are similar; but if it prevail here

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and be vanquished there, then the one is female and the other male. (For whether we consider the reason why
the whole animal is male or female, or why the parts are so, makes no difference.)

When we meet with deficiency in such parts, e.g. an extremity or one of the other members, we must assume
the same cause as when the embryo is altogether aborted (abortion of embryos happens frequently).

Outgrowths differ from the production of many young in the manner stated before; monsters differ from these
in that most of them are due to embryos growing together. Some however are also of the following kind,
when the monstrosity affects greater and more sovereign parts, as for instance some monsters have two
spleens or more than two kidneys. Further, the parts may migrate, the movements which form the embryo
being diverted and the material changing its place. We must decide whether the monstrous animal is one or is
composed of several grown together by considering the vital principle; thus, if the heart is a part of such a
kind then that which has one heart will be one animal, the multiplied parts being mere outgrowths, but those
which have more than one heart will be two animals grown together through their embryos having been
confused.

It also often happens even in many animals that do not seem to be defective and whose growth is now
complete, that some of their passages may have grown together or others may have been diverted from the
normal course. Thus in some women before now the os uteri has remained closed, so that when the time for
the catamenia has arrived pain has attacked them, till either the passage has burst open of its own accord or
the physicians have removed the impediment; some such cases have ended in death if the rupture has been
made too violently or if it has been impossible to make it at all. In some boys on the other hand the end of the
penis has not coincided with the end of the passage where the urine is voided, but the passage has ended
below, so that they crouch sitting to void it, and if the testes are drawn up they appear from a distance to have
both male and female generative organs. The passage of the solid food also has been closed before now in
sheep and some other animals; there was a cow in Perinthus which passed fine matter, as if it were sifted,
through the bladder, and when the anus was cut open it quickly closed up again nor could they succeed in
keeping it open.

We have now spoken of the production of few and many young, and of the outgrowth of superfluous parts or
of their deficiency, and also of monstrosities.

Superfoetation does not occur at all in some animals but does in others; of the former some are able to bring
the later formed embryo to birth, while others can only do so sometimes. The reason why it does not occur in
some is that they produce only one young one, for it is not found in solid-hoofed animals and those larger
than these, as owing to their size the secretion of the female is all used up for the one embryo. For all these
have large bodies, and when an animal is large its foetus is large in proportion, e.g. the foetus of the elephant
is as big as a calf. But superfoetation occurs in those which produce many young because the production of
more than one at a birth is itself a sort of superfoetation, one being added to another. Of these all that are
large, as man, bring to birth the later embryo, if the second impregnation takes place soon after the first, for
such an event has been observed before now. The reason is that given above, for even in a single act of
intercourse the semen discharged is more than enough for one embryo, and this being divided causes more
than one child to be born, the one of which is later than the other. But when the embryo has already grown to
some size and it so happens that copulation occurs again, superfoetation sometimes takes place, but rarely,
since the uterus generally closes in women during the period of gestation. If this ever happens (for this also
has occurred) the mother cannot bring the second embryo to perfection, but it is cast out in a state like what
are called abortions. For just as, in those animals that bear only one, all the secretion of the female is
converted to the first formed embryo because of its size, so it is here also; the only difference is that in the

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former case this happens at once, in the latter when the foetus has attained to some size, for then they are in
the same state as those that bear only one. In like manner, since man naturally would produce many young,
and since the size of the uterus and the quantity of the female secretion are both greater than is necessary for
one embryo, only not so much so as to bring to birth a second, therefore women and mares are the only
animals which admit the male during gestation, the former for the reason stated, and mares both because of
the barrenness of their nature and because their uterus is of superfluous size, too large for one but too small to
allow a second embryo to be brought to perfection by superfoetation. And the mare is naturally inclined to
sexual intercourse because she is in the same case as the barren among women; these latter are barren
because they have no monthly discharge (which corresponds to the act of intercourse in males) and mares
have exceedingly little. And in all the vivipara the barren females are so inclined, because they resemble the
males when the semen has collected in the testes but is not being got rid of. For the discharge of the
catamenia is in females a sort of emission of semen, they being unconcocted semen as has been said before.
Hence it is that those women also who are incontinent in regard to such intercourse cease from their passion
for it when they have borne many children, for, the seminal secretion being then drained off, they no longer
desire this intercourse. And among birds the hens are less disposed that way than the cocks, because the
uterus of the hen-bird is up near the hypozoma; but with the cock-birds it is the other way, for their testes are
drawn up within them, so that, if any kind of such birds has much semen naturally, it is always in need of this
intercourse. In females then it encourages copulation to have the uterus low down, but in males to have the
testes drawn up.

It has been now stated why superfoetation is not found in some animals at all, why it is found in others which
sometimes bring the later embryos to birth and sometimes not, and why some such animals are inclined to
sexual intercourse while others are not.

Some of those animals in which superfoetation occurs can bring the embryos to birth even if a long time
elapses between the two impregnations, if their kind is spermatic, if their body is not of a large size, and if
they bear many young. For because they bear many their uterus is spacious, because they are spermatic the
generative discharge is copious, and because the body is not large but the discharge is excessive and in
greater measure than is required for the nourishment wanted for the embryo, therefore they can not only form
animals but also bring them to birth later on. Further, the uterus in such animals does not close up during
gestation because there is a quantity of the residual discharge left over. This has happened before now even in
women, for in some of them the discharge continues during all the time of pregnancy. In women, however,
this is contrary to Nature, so that the embryo suffers, but in such animals it is according to Nature, for their
body is so formed from the beginning, as with hares. For superfoetation occurs in these animals, since they
are not large and they bear many young (for they have many toes and the many-toed animals bear many),
and they are spermatic. This is shown by their hairiness, for the quantity of their hair is excessive, these
animals alone having hair under the feet and within the jaws. Now hairiness is a sign of abundance of residual
matter, wherefore among men also the hairy are given to sexual intercourse and have much semen rather than
the smooth. In the hare it often happens that some of the embryos are imperfect while others of its young are
produced perfect.

Some of the vivipara produce their young imperfect, others perfect; the one-hoofed and cloven-footed
perfect, most of the many-toed imperfect. The reason of this is that the one-hoofed produce one young one,
and the cloven-footed either one or two generally speaking; now it is easy to bring the few to perfection. All
the many-toed animals that bear their young imperfect give birth to many. Hence, though they are able to
nourish the embryos while newly formed, their bodies are unable to complete the process when the embryos
have grown and acquired some size. So they produce them imperfect, like those animals which generate a
scolex, for some of them when born are scarcely brought into form at all, as the fox, bear, and lion, and some

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of the rest in like manner; and nearly all of them are blind, as not only the animals mentioned but also the
dog, wolf, and jackal. The pig alone produces both many and perfect young, and thus here alone we find any
overlapping; it produces many as do the many-toed animals, but is cloven-footed or solid-hoofed (for there
certainly are solid-hoofed swine). They bear, then, many young because the nutriment which would
otherwise go to increase their size is diverted to the generative secretion (for considered as a solid-hoofed
animal the pig is not a large one), and also it is more often cloven-hoofed, striving as it were with the nature
of the solid-hoofed animals. For this reason it produces sometimes only one, sometimes two, but generally
many, and brings them to perfection before birth because of the good condition of its body, being like a rich
soil- which has sufficient and abundant nutriment for plants.

The young of some birds also are hatched imperfect, that is to say blind; this applies to all small birds which
lay many eggs, as crows and rooks, jays, sparrows, swallows, and to all those which lay few eggs without
producing abundant nourishment along with the young, as ring-doves, turtle-doves, and pigeons. Hence if
the eyes of swallows while still young be put out they recover their sight again, for the birds are still
developing, not yet developed, when the injury is inflicted, so that the eyes grow and sprout afresh. And in
general the production of young before they are perfect is owing to inability to continue nourishing them, and
they are born imperfect because they are born too soon. This is plain also with seven-months children, for
since they are not perfected it often happens that even the passages, e.g. of the ears and nostrils, are not yet
opened in some of them at birth, but only open later as they are growing, and many such infants survive.

In man males are more often born defective than females, but in the other animals this is not the case. The
reason is that in man the male is much superior to the female in natural heat, and so the male foetus moves
about more than the female, and on account of moving is more liable to injury, for what is young is easily
injured since it is weak. For this same reason also the female foetus is not perfected equally with the male in
man (but they are so in the other animals, for in them the female is not later in developing than the male). For
while within the mother the female takes longer in developing, but after birth everything is perfected more
quickly in females than in males; I mean, for instance, puberty, the prime of life, and old age. For females are
weaker and colder in nature, and we must look upon the female character as being a sort of natural
deficiency. Accordingly while it is within the mother it develops slowly because of its coldness (for
development is concoction, and it is heat that concocts, and what is hotter is easily concocted); but afterbirth
it quickly arrives at maturity and old age on account of its weakness, for all inferior things come sooner to
their perfection or end, and as this is true of works of art so it is of what is formed by Nature. For the reason
just given also twins are less likely to survive in man if one be male and one female, but this is not at all so in
the other animals; for in man it is contrary to Nature that they should run an equal course, as their
development does not take place in equal periods, but the male must needs be too late or the female too early;
in the other animals, however, it is not contrary to Nature. A difference is also found between man and the
other animals in respect of gestation, for animals are in better bodily condition most of the time, whereas in
most women gestation is attended with discomfort. Their way of life is partly responsible for this, for being
sedentary they are full of more residual matter; among nations where the women live a laborious life
gestation is not equally conspicuous and those who are accustomed to work bear children easily both there
and elsewhere; for work consumes the residual matter, but those who are sedentary have a great deal of it in
them because not only is there no monthly discharge during pregnancy but also they do no work; therefore
their travail is painful. But work exercises them so that they can hold their breath, upon which depends the
ease or difficulty of child-birth. These circumstances then, as we have said, contribute to cause the difference
between women and the other animals in this state, but the most important thing is this: in some animals the
discharge corresponding to the catamenia is but small, and in some not visible at all, but in women it is
greater than in any other animal, so that when this discharge ceases owing to pregnancy they are troubled (for
if they are not pregnant they are afflicted with ailments whenever the catamenia do not occur); and they are
more troubled as a rule at the beginning of pregnancy, for the embryo is able indeed to stop the catamenia but
is too small at first to consume any quantity of the secretion; later on it takes up some of it and so alleviates
the mother. In the other animals, on the contrary, the residual matter is but small and so corresponds with the

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growth of the foetus, and as the secretions which hinder nourishment are being consumed by the foetus the
mother is in better bodily condition than usual. The same holds good also with aquatic animals and birds. If it
ever happens that the body of the mother is no longer in good condition when the foetus is now becoming
large, the reason is that its growth needs more nourishment than the residual matter supplies. (In some few
women it happens that the body is in a better state during pregnancy; these are women in whose body the
residual matter is small so that it is all used up along with the nourishment that goes to the foetus.)

We must also speak of what is known as mola uteri, which occurs rarely in women but still is found
sometimes during pregnancy. For they produce what is called a mola; it has happened before now to a
woman, after she had had intercourse with her husband and supposed she had conceived, that at first the size
of her belly increased and everything else happened accordingly, but yet when the time for birth came on, she
neither bore a child nor was her size reduced, but she continued thus for three or four years until dysentery
came on, endangering her life, and she produced a lump of flesh which is called mola. Moreover this
condition may continue till old age and death. Such masses when expelled from the body become so hard that
they can hardly be cut through even by iron. Concerning the cause of this phenomenon we have spoken in the
Problems; the same thing happens to the embryo in the womb as to meats half cooked in roasting, and it is
not due to heat, as some say, but rather to the weakness of the maternal heat. (For their nature seems to be
incapable, and unable to perfect or to put the last touches to the process of generation. Hence it is that the
mola remains in them till old age or at any rate for a long time, for in its nature it is neither perfect nor
altogether a foreign body.) It is want of concoction that is the reason of its hardness, as with half-cooked
meat, for this half-dressing of meat is also a sort of want of concoction.

A difficulty is raised as to why this does not occur in other animals, unless indeed it does occur and has
entirely escaped observation. We must suppose the reason to be that woman alone among animals is subject
to troubles of the uterus, and alone has a superfluous amount of catamenia and is unable to concoct them;
when, then, the embryo has been formed of a liquid hard to concoct, then comes the so-called mola into
being, and this happens naturally in women alone or at any rate more than in other animals.

Milk is formed in the females of all internally viviparous animals, becoming useful for the time of birth. For
Nature has made it for the sake of the nourishment of animals after birth, so that it may neither fail at this
time at all nor yet be at all superfluous; this is just what we find happening, unless anything chance contrary
to Nature. In the other animals the period of gestation does not vary, and so the milk is concocted in time to
suit this moment, but in man, since there are several times of birth, it must be ready at the first of these; hence
in women the milk is useless before the seventh month and only then becomes useful. That it is only
concocted at the last stages is what we should expect to happen also as being due to a necessary cause. For at
first such residual matter when secreted is used up for the development of the embryo; now the nutritious part
in all things is the sweetest and the most concocted, and thus when all such elements are removed what
remains must become of necessity bitter and ill-flavoured. As the embryo is perfecting, the residual matter
left over increases in quantity because the part consumed by the embryo is less; it is also sweeter since the
easily concocted part is less drawn away from it. For it is no longer expended on moulding the embryo but
only on slightly increasing its growth, it being now fixed because it has reached perfection (for in a sense
there is a perfection even of an embryo). Therefore it comes forth from the mother and changes its mode of
development, as now possessing what belongs to it; and no longer takes that which does not belong to it; and
it is at this season that the milk becomes useful.

ON THE GENERATION OF ANIMALS

The milk collects in the upper part of the body and the breasts because of the original plan of the organism.
For the part above the hypozoma is the sovereign part of the animal, while that below is concerned with
nourishment and residual matter, in order that all animals which move about may contain within themselves
nourishment enough to make them independent when they move from one place to another. From this upper
part also is produced the generative secretion for the reason mentioned in the opening of our discussion. But
both the secretion of the male and the catamenia of the female are of a sanguineous nature, and the first
principle of this blood and of the blood-vessels is the heart, and the heart is in this part of the body.
Therefore it is here that the change of such a secretion must first become plain. This is why the voice changes
in both sexes when they begin to bear seed (for the first principle of the voice resides there, and is itself
changed when its moving cause changes). At the same time the parts about the breasts are raised visibly even
in males but still more in females, for the region of the breasts becomes empty and spongy in them because so
much material is drained away below. This is so not only in women but also in those animals which have the
mammae low down.

This change in the voice and the parts about the mammae is plain even in other creatures to those who have
experience of each kind of animal, but is most remarkable in man. The reason is that in man the production of
secretion is greatest in both sexes in proportion to their size as compared with other animals; I mean that of
the catamenia in women and the emission of semen in men. When, therefore, the embryo no longer takes up
the secretion in question but yet prevents its being discharged from the mother, it is necessary that the
residual matter should collect in all those empty parts which are set upon the same passages. And such is the
position of the mammae in each kind of animals for both causes; it is so both for the sake of what is best and
of necessity.

It is here, then, that the nourishment in animals is now formed and becomes thoroughly concocted. As for the
cause of concoction, we may take that already given, or we may take the opposite, for it is a reasonable view
also that the embryo being larger takes more nourishment, so that less is left over about this time, and the less
is concocted more quickly.

That milk has the same nature as the secretion from which each animal is formed is plain, and has been stated
previously. For the material which nourishes is the same as that from which Nature forms the animal in
generation. Now this is the sanguineous liquid in the sanguinea, and milk is blood concocted (not corrupted;
Empedocles either mistook the fact or made a bad metaphor when he composed the line: 'On the tenth day of
the eighth month the milk comes into being, a white pus', for putrefaction and concoction are opposite things,
and pus is a kind of putrefaction but milk is concocted). While women are suckling children the catamenia do
not occur according to Nature, nor do they conceive; if they do conceive, the milk dries up. This is because
the nature of the milk and of the catamenia is the same, and Nature cannot be so productive as to supply both
at once; if the secretion is diverted in the one direction it must needs cease in the other, unless some violence
is done contrary to the general rule. But this is as much as to say that it is contrary to Nature, for in all cases
where it is not impossible for things to be otherwise than they generally are but where they may so happen,
still what is the general rule is what is 'according to Nature'.

The time also at which the young animal is born has been well arranged. For when the nourishment coming
through the umbilical cord is no longer sufficient for the foetus because of its size, then at the same time the
milk becomes useful for the nourishment of the newly-born animal, and the blood-vessels round which the
so-called umbilical cord lies as a coat collapse as the nourishment is no longer passing through it; for these
reasons it is at that time also that the young animal enters into the world.

The natural birth of all animals is head-foremost, because the parts above the umbilical cord are larger than
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those below. The body then, being suspended from the cord as in a balance, inclines towards the heavy end,
and the larger parts are the heavier.

The period of gestation is, as a matter of fact, determined generally in each animal in proportion to the length
of its life. This we should expect, for it is reasonable that the development of the long-lived animals should
take a longer time. Yet this is not the cause of it, but the periods only correspond accidentally for the most
part; for though the larger and more perfect sanguinea do live a long time, yet the larger are not all
longer-lived. Man lives a longer time than any animal of which we have any credible experience except the
elephant, and yet the human kind is smaller than that of the bushy-tailed animals and many others. The real
cause of long life in any animal is its being tempered in a manner resembling the environing air, along with
certain other circumstances of its nature, of which we will speak later; but the cause of the time of gestation is
the size of the offspring. For it is not easy for large masses to arrive at their perfection in a small time,
whether they be animals or, one may say, anything else whatever. That is why horses and animals akin to
them, though living a shorter time than man, yet carry their young longer; for the time in the former is a year,
but in the latter ten months at the outside. For the same reason also the time is long in elephants; they carry
their young two years on account of their excessive size.

We find, as we might expect, that in all animals the time of gestation and development and the length of life
aims at being measured by naturally complete periods. By a natural period I mean, e.g. a day and night, a
month, a year, and the greater times measured by these, and also the periods of the moon, that is to say, the
full moon and her disappearance and the halves of the times between these, for it is by these that the moon's
orbit fits in with that of the sun [the month being a period common to both] .

The moon is a first principle because of her connexion with the sun and her participation in his light, being as
it were a second smaller sun, and therefore she contributes to all generation and development. For heat and
cold varying within certain limits make things to come into being and after this to perish, and it is the motions
of the sun and moon that fix the limit both of the beginning and of the end of these processes. Just as we see
the sea and all bodies of water settling and changing according to the movement or rest of the winds, and the
air and winds again according to the course of the sun and moon, so also the things which grow out of these
or are in these must needs follow suit. For it is reasonable that the periods of the less important should follow
those of the more important. For in a sense a wind, too, has a life and birth and death.

As for the revolutions of the sun and moon, they may perhaps depend on other principles. It is the aim, then,
of Nature to measure the coming into being and the end of animals by the measure of these higher periods,
but she does not bring this to pass accurately because matter cannot be easily brought under rule and because
there are many principles which hinder generation and decay from being according to Nature, and often cause
things to fall out contrary to Nature.

We have now spoken of the nourishment of animals within the mother and of their birth into the world, both
of each kind separately and of all in common.

BookV

WE must now investigate the qualities by which the parts of animals differ. I mean such qualities of the parts
as blueness and blackness in the eyes, height and depth of pitch in the voice, and differences in colour
whether of the skin or of hair and feathers. Some such qualities are found to characterize the whole of a kind

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of animals sometimes, while in other kinds they occur at random, as is especially the case in man. Further, in
connexion with the changes in the time of life, all animals are alike in some points, but are opposed in others
as in the case of the voice and the colour of the hair, for some do not grow grey visibly in old age, while man
is subject to this more than any other animal. And some of these affections appear immediately after birth,
while others become plain as age advances or in old age.

Now we must no longer suppose that the cause of these and all such phenomena is the same. For whenever
things are not the product of Nature working upon the animal kingdom as a whole, nor yet characteristic of
each separate kind, then none of these things is such as it is or is so developed for any final cause. The eye for
instance exists for a final cause, but it is not blue for a final cause unless this condition be characteristic of the
kind of animal. In fact in some cases this condition has no connexion with the essence of the animal's being,
but we must refer the causes to the material and the motive principle or efficient cause, on the view that these
things come into being by Necessity. For, as was said originally in the outset of our discussion, when we are
dealing with definite and ordered products of Nature, we must not say that each is of a certain quality because
it becomes so, but rather that they become so and so because they are so and so, for the process of Becoming
or development attends upon Being and is for the sake of Being, not vice versa.

The ancient Nature-philosophers however took the opposite view. The reason of this is that they did not see
that the causes were numerous, but only saw the material and efficient and did not distinguish even these,
while they made no inquiry at all into the formal and final causes.

Everything then exists for a final cause, and all those things which are included in the definition of each
animal, or which either are means to an end or are ends in themselves, come into being both through this
cause and the rest. But when we come to those things which come into being without falling under the heads
just mentioned, their course must be sought in the movement or process of coming into being, on the view
that the differences which mark them arise in the actual formation of the animal. An eye, for instance, the
animal must have of necessity (for the fundamental idea of the animal is of such a kind), but it will have an
eye of a particular kind of necessity in another sense, not the sense mentioned just above, because it is its
nature to act or be acted on in this or that way.

These distinctions being drawn let us speak of what comes next in order. As soon then as the offspring of all
animals are born, especially those born imperfect, they are in the habit of sleeping, because they continue
sleeping also within the mother when they first acquire sensation. But there is a difficulty about the earliest
period of development, whether the state of wakefulness exists in animals first, or that of sleep. Since they
plainly wake up more as they grow older, it is reasonable to suppose that the opposite state, that of sleep,
exists in the first stages of development. Moreover the change from not being to being must pass through the
intermediate condition, and sleep seems to be in its nature such a condition, being as it were a boundary
between living and not living, and the sleeper being neither altogether non-existent nor yet existent. For life
most of all appertains to wakefulness, on account of sensation. But on the other hand, if it is necessary that
the animal should have sensation and if it is then first an animal when it has acquired sensation, we ought to
consider the original condition to be not sleep but only something resembling sleep, such a condition as we
find also in plants, for indeed at this time animals do actually live the life of a plant. But it is impossible that
plants should sleep, for there is no sleep which cannot be broken, and the condition in plants which is
analogous to sleep cannot be broken.

It is necessary then for the embryo animal to sleep most of the time because the growth takes place in the
upper part of the body, which is consequently heavier (and we have stated elsewhere that such is the cause of
sleep). But nevertheless they are found to wake even in the womb (this is clear in dissections and in the
ovipara), and then they immediately fall into a sleep again. This is why after birth also they spend most of
their time in sleep.

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When awake infants do not laugh, but while asleep they both laugh and cry. For animals have sensations even
while asleep, not only what are called dreams but also others besides dreams, as those persons who arise
while sleeping and do many things without dreaming. For there are some who get up while sleeping and walk
about seeing just like those who are awake; these have perception of what is happening, and though they are
not awake, yet this perception is not like a dream. So infants presumably have sense-perception and live in
their sleep owing to previous habit, being as it were without knowledge of the waking state. As time goes on
and their growth is transferred to the lower part of the body, they now wake up more and spend most of their
time in that condition. Children continue asleep at first more than other animals, for they are born in a more
imperfect condition than other animals that are produced in anything like a perfect state, and their growth has
taken place more in the upper part of the body.

The eyes of all children are bluish immediately after birth; later on they change to the colour which is to be
theirs permanently. But in the case of other animals this is not visible. The reason of this is that the eyes of
other animals are more apt to have only one colour for each kind of animal; e.g. cattle are dark-eyed, the eye
of all sheep is pale, of others again the whole kind is blue or grey-eyed, and some are yellow (goat-eyed), as
the majority of goats themselves, whereas the eyes of men happen to be of many colours, for they are blue or
grey or dark in some cases and yellow in others. Hence, as the individuals in other kinds of animals do not
differ from one another in the colour, so neither do they differ from themselves, for they are not of a nature to
have more than one colour. Of the other animals the horse has the greatest variety of colour in the eye, for
some of them are actually heteroglaucous; this phenomenon is not to be seen in any of the other animals, but
man is sometimes heteroglaucous.

Why then is it that there is no visible change in the other animals if we compare their condition when newly
born with their condition at a more advanced age, but that there is such a change in children? We must
consider just this to be a sufficient cause, that the part concerned has only one colour in the former but several
colours in the latter. And the reason why the eyes of infants are bluish and have no other colour is that the
parts are weaker in the newly born and blueness is a sort of weakness.

We must also gain a general notion about the difference in eyes, for what reason some are blue, some grey,
some yellow, and some dark. To suppose that the blue are fiery, as Empedocles says, while the dark have
more water than fire in them, and that this is why the former, the blue, have not keen sight by day, viz. owing
to deficiency of water in their composition, and the latter are in like condition by night, viz. owing to
deficiency of fire- this is not well said if indeed we are to assume sight to be connected with water, not fire,
in all cases. Moreover it is possible to render another account of the cause of the colours, but if indeed the
fact is as was stated before in the treatise on the senses, and still earlier than that in the investigations
concerning soul- if this sense organ is composed of water and if we were right in saying for what reason it is
composed of water and not of air or fire- then we must assume the water to be the cause of the colours
mentioned. For some eyes have too much liquid to be adapted to the movement, others have too little, others
the due amount. Those eyes therefore in which there is much liquid are dark because much liquid is not
transparent, those which have little are blue; (so we find in the sea that the transparent part of it appears light
blue, the less transparent watery, and the unfathomable water is dark or deep-blue on account of its depth).
When we come to the eyes between these, they differ only in degree.

We must suppose the same cause also to be responsible for the fact that blue eyes are not keen-sighted by
day nor dark eyes by night. Blue eyes, because there is little liquid in them, are too much moved by the light
and by visible objects in respect of their liquidity as well as their transparency, but sight is the movement of
this part in so far as it is transparent, not in so far as it is liquid. Dark eyes are less moved because of the
quantity of liquid in them. And so they see less well in the dusk, for the nocturnal light is weak; at the same
time also liquid is in general hard to move in the night. But if the eye is to see, it must neither not be moved
at all nor yet more than in so far as it is transparent, for the stronger movement drives out the weaker. Hence
it is that on changing from strong colours, or on going out of the sun into the dark, men cannot see, for the

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motion already existing in the eye, being strong, stops that from outside, and in general neither a strong nor a
weak sight can see bright things because the liquid is acted upon and moved too much.

The same thing is shown also by the morbid affections of each kind of sight. Cataract attacks the blue-eyed
more, but what is called 'nyctalopia' the dark-eyed. Now cataract is a sort of dryness of the eyes and therefore
it is found more in the aged, for this part also like the rest of the body gets dry towards old age; but is an
excess of liquidity and so is found more in the younger, for their brain is more liquid.

The sight of the eye which is intermediate between too much and too little liquid is the best, for it has neither
too little so as to be disturbed and hinder the movement of the colours, nor too much so as to cause difficulty
of movement.

Not only the above-mentioned facts are causes of seeing keenly or the reverse, but also the nature of the skin
upon what is called the pupil. This ought to be transparent, and it is necessary that the transparent should be
thin and white and even, thin that the movement coming from without may pass straight through it, even that
it may not cast a shade the liquid behind it by wrinkling (for this also is a reason why old men have not keen
sight, the skin of the eye like the rest of the skin wrinkling and becoming thicker in old age), and white
because black is not transparent, for that is just what is meant by 'black', what is not shone through, and that is
why lanterns cannot give light if they be made of black skin. It is for these reasons then that the sight is not
keen in old age nor in the diseases in question, but it is because of the small amount of liquid that the eyes of
children appear blue at first.

And the reason why men especially and horses occasionally are heteroglaucous is the same as the reason why
man alone grows grey and the horse is the only other animal whose hairs whiten visibly in old age. For
greyness is a weakness of the fluid in the brain and an incapacity to concoct properly, and so is blueness of
the eyes; excess of thinness or of thickness produces the same effect, according as this liquidity is too little or
too much. Whenever then Nature cannot make the eyes correspond exactly, either by concocting or by not
concocting the liquid in both, but concocts the one and not the other, then the result is heteroglaucia.

The cause of some animals being keen-sighted and others not so is not simple but double. For the word 'keen'
has pretty much a double sense (and this is the case in like manner with hearing and smelling). In one sense
keen sight means the power of seeing at a distance, in another it means the power of distinguishing as
accurately as possible the objects seen. These two faculties are not necessarily combined in the same
individual. For the same person, if he shades his eyes with his hand or look through a tube, does not
distinguish the differences of colour either more or less in any way, but he will see further; in fact, men in pits
or wells sometimes see the stars. Therefore if any animal's brows project far over the eye, but if the liquid in
the pupil is not pure nor suited to the movement coming from external objects and if the skin over the surface
is not thin, this animal will not distinguish accurately the differences of the colours but it will be able to see
from a long distance (just as it can from a short one) better than those in which the liquid and the covering
membrane are pure but which have no brows projecting over the eyes. For the cause of seeing keenly in the
sense of distinguishing the differences is in the eye itself; as on a clean garment even small stains are visible,
so also in a pure sight even small movements are plain and cause sensation. But it is the position of the eyes
that is the cause of seeing things far off and of the movements in the transparent medium coming to the eyes
from distant objects. A proof of this is that animals with prominent eyes do not see well at a distance,
whereas those which have their eyes lying deep in the head can see things at a distance because the
movement is not dispersed in space but comes straight to the eye. For it makes no difference whether we say,
as some do, that seeing is caused by the sight going forth from the eye- on that view, if there is nothing
projecting over the eyes, the sight must be scattered and so less of it will fall on the objects of vision and
things at a distance will not be seen so well- or whether we say that seeing is due to the movement coming
from the objects; for the sight also must see, in a manner resembling the movement. Things at a distance,
then, would be seen best if there were, so to say, a continuous tube straight from the sight to its object, for the

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movement from the object would not then be dissipated; but, if that is impossible, still the further the tube
extends the more accurately must distant objects be seen.

Let these, then, be given as the causes of the difference in eyes.

It is the same also with hearing and smell; to hear and smell accurately mean in one sense to perceive as
precisely as possible all the distinctions of the objects of perception, in another sense to hear and smell far
off. As with sight, so here the sense-organ is the cause of judging well the distinctions, if both that organ
itself and the membrane round it be pure. For the passages of all the sense-organs, as has been said in the
treatise on sensation, run to the heart, or to its analogue in creatures that have no heart. The passage of the
hearing, then, since this sense-organ is of air, ends at the place where the innate spiritus causes in some
animals the pulsation of the heart and in others respiration; wherefore also it is that we are able to understand
what is said and repeat what we have heard, for as was the movement which entered through the
sense-organ, such again is the movement which is caused by means of the voice, being as it were of one and
the same stamp, so that a man can say what he has heard. And we hear less well during a yawn or expiration
than during inspiration, because the starting-point of the sense-organ of hearing is set upon the part
concerned with breathing and is shaken and moved as the organ moves the breath, for while setting the breath
in motion it is moved itself. The same thing happens in wet weather or a damp atmosphere.... And the ears
seemed to be filled with air because their starting-point is near the region of breathing.

Accuracy then in judging the differences of sounds and smells depends on the purity of the sense-organ and
of the membrane lying upon its surface, for then all the movements become clear in such cases, as in the case
of sight. Perception and non-perception at a distance also depend on the same things with hearing and smell
as with sight. For those animals can perceive at a distance which have channels, so to say, running through
the parts concerned and projecting far in front of the sense-organs. Therefore all animals whose nostrils are
long, as the Laconian hounds, are keen-scented, for the sense-organ being above them, the movements from
a distance are not dissipated but go straight to the mark, just as the movements which cause sight do with
those who shadow the eyes with the hand.

Similar is the case of animals whose ears are long and project far like the eaves of a house, as in some
quadrupeds, with the internal spiral passage long; these also catch the movement from afar and pass it on to
the sense-organ.

In respect of sense-perception at a distance, man is, one may say, the worst of all animals in proportion to his
size, but in respect of judging the differences of quality in the objects he is the best of all. The reason is that
the sense-organ in man is pure and least earthy and material, and he is by nature the thinnest-skinned of all
animals for his size.

The workmanship of Nature is admirable also in the seal, for though a viviparous quadruped it has no ears but
only passages for hearing. This is because its life is passed in the water; now the ear is a part added to the
passages to preserve the movement of the air at a distance; therefore an ear is no use to it but would even
bring about the contrary result by receiving a mass of water into itself.

We have thus spoken of sight, hearing, and smell.

ON THE GENERATION OF ANIMALS

As for hair, men differ in this themselves at different ages, and also from all other kinds of animals that have
hair. These are almost all which are internally viviparous, for even when the covering of such animals is
spiny it must be considered as a kind of hair, as in the land hedgehog and any other such animal among the
vivipara. Hairs differ in respect of hardness and softness, length and shortness, straightness and curliness,
quantity and scantiness, and in addition to these qualities, in their colours, whiteness and blackness and the
intermediate shades. They differ also in some of these respects according to age, as they are young or
growing old. This is especially plain in man; the hair gets coarser as time goes on, and some go bald on the
front of the head; children indeed do not go bald, nor do women, but men do so by the time their age is
advancing. Human beings also go grey on the head as they grow old, but this is not visible in practically any
other animal, though more so in the horse than others. Men go bald on the front of the head, but turn grey first
on the temples; no one goes bald first on these or on the back of the head. Some such affections occur in a
corresponding manner also in all animals which have not hair but something analogous to it, as the feathers of
birds and scales in the class of fish.

For what purpose Nature has made hair in general for animals has been previously stated in the work dealing
with the causes of the parts of animals; it is the business of the present inquiry to show under what
circumstances and for what necessary causes each particular kind of hair occurs. The principal cause then of
thickness and thinness is the skin, for this is thick in some animals and thin in others, rare in some and dense
in others. The different quality of the included moisture is also a helping cause, for in some animals this is
greasy and in others watery. For generally speaking the substratum of the skin is of an earthy nature; being on
the surface of the body it becomes solid and earthy as the moisture evaporates. Now the hairs or their
analogue are not formed out of the flesh but out of the skin moisture evaporating and exhaling in them, and
therefore thick hairs arise from a thick skin and thin from thin. If then the skin is rarer and thicker, the hairs
are thick because of the quantity of earthy matter and the size of the pores, but if it is denser they are thin
because of the narrowness of the pores. Further, if the moisture be watery it dries up quickly and the hairs do
not gain in size, but if it be greasy the opposite happens, for the greasy is not easily dried up. Therefore the
thicker-skinned animals are as a general rule thicker-haired for the causes mentioned; however, the
thickest-skinned are not more so than other thick-skinned ones, as is shown by the class of swine compared
to that of oxen and to the elephant and many others. And for the same reason also the hairs of the head in man
are thickest, for this part of his skin is thickest and lies over most moisture and besides is very porous.

The cause of the hairs being long or short depends on the evaporating moisture not being easily dried. Of this
there are two causes, quantity and quality; if the liquid is much it does not dry up easily nor if it is greasy.
And for this reason the hairs of the head are longest in man, for the brain, being fluid and cold, supplies great
abundance of moisture.

The hairs become straight or curly on account of the vapour arising in them. If it be smoke-like, it is hot and
dry and so makes the hair curly, for it is twisted as being carried with a double motion, the earthy part tending
downwards and the hot upwards. Thus, being easily bent, it is twisted owing to its weakness, and this is what
is meant by curliness in hair. It is possible then that this is the cause, but it is also possible that, owing to its
having but little moisture and much earthy matter in it, it is dried by the surrounding air and so coiled up
together. For what is straight becomes bent, if the moisture in it is evaporated, and runs together as a hair
does when burning upon the fire; curliness will then be a contraction owing to deficiency of moisture caused
by the heat of the environment. A sign of this is the fact that curly hair is harder than straight, for the dry is
hard. And animals with much moisture are straight-haired; for in these hairs the moisture advances as a
stream, not in drops. For this reason the Scythians on the Black Sea and the Thracians are straight-haired, for
both they themselves and the environing air are moist, whereas the Aethiopians and men in hot countries are
curly-haired, for their brains and the surrounding air are dry.

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Some, however, of the thick-skinned animals are fine-haired for the cause previously stated, for the finer the
pores are the finer must the hairs be. Hence the class of sheep have such hairs (for wool is only a multitude of
hairs).

There are some animals whose hair is soft and yet less fine, as is the case with the class of hares compared
with that of sheep; in such animals the hair is on the surface of the skin, not deeply rooted in it, and so is not
long but in much the same state as the scrapings from linen, for these also are not long but are soft and do not
admit of weaving.

The condition of sheep in cold climates is opposite to that of man; the hair of the Scythians is soft but that of
the Sauromatic sheep is hard. The reason of this is the same as it is also all wild animals. The cold hardens
and solidifies them by drying them, for as the heat is pressed out the moisture evaporates, and both hair and
skin become earthy and hard. In wild animals then the exposure to the cold is the cause of hardness in the
hair, in the others the nature of the climate is the cause. A proof of this is also what happens in the
sea-urchins which are used as a remedy in stranguries. For these, too, though small themselves, have large
and hard spines because the sea in which they live is cold on account of its depth (for they are found in sixty
fathoms and even more). The spines are large because the growth of the body is diverted to them, since
having little heat in them they do not concoct their nutriment and so have much residual matter and it is from
this that spines, hairs, and such things are formed; they are hard and petrified through the congealing effect of
the cold. In the same way also plants are found to be harder, more earthy, and stony, if the region in which
they grow looks to the north than if it looks to the south, and those in windy places than those in sheltered, for
they are all more chilled and their moisture evaporates.

Hardening, then, comes of both heat and cold, for both cause the moisture to evaporate, heat per se and cold
per accidens (since the moisture goes out of things along with the heat, there being no moisture without heat),
but whereas cold not only hardens but also condenses, heat makes a substance rarer.

For the same reason, as animals grow older, the hairs become harder in those which have hairs, and the
feathers and scales in the feathered and scaly kinds. For their skins become harder and thicker as they get
older, for they are dried up, and old age, as the word denotes, is earthy because the heat fails and the moisture
along with it.

Men go bald visibly more than any other animal, but still such a state is something general, for among plants
also some are evergreens while others are deciduous, and birds which hibernate shed their feathers. Similar to
this is the condition of baldness in those human beings to whom it is incident. For leaves are shed by all
plants, from one part of the plant at a time, and so are feathers and hairs by those animals that have them; it is
when they are all shed together that the condition is described by the terms mentioned, for it is called 'going
bald' and 'the fall of the leaf and 'moulting'. The cause of the condition is deficiency of hot moisture, such
moisture being especially the unctuous, and hence unctuous plants are more evergreen. (However we must
elsewhere state the cause of this phenomena in plants, for other causes also contribute to it.) It is in winter
that this happens to plants (for the change from summer to winter is more important to them than the time of
life), and to those animals which hibernate (for these, too, are by nature less hot and moist than man); in the
latter it is the seasons of life that correspond to summer and winter. Hence no one goes bald before the time
of sexual intercourse, and at that time it is in those naturally inclined to such intercourse that baldness
appears, for the brain is naturally the coldest part of the body and sexual intercourse makes men cold, being a
loss of pure natural heat. Thus we should expect the brain to feel the effect of it first, for a little cause turns
the scale where the thing concerned is weak and in poor condition. Thus if we reckon up these points, that the
brain itself has but little heat, and further that the skin round it must needs have still less, and again that the
hair must have still less than the skin inasmuch as it is furthest removed from the brain, we should reasonably
expect baldness to come about this age upon those who have much semen. And it is for the same reason that
the front part of the head alone goes bald in man and that he is the only animal to do so; the front part goes

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bald because the brain is there, and man is the only animal to go bald because his brain is much the largest
and the moistest. Women do not go bald because their nature is like that of children, both alike being
incapable of producing seminal secretion. Eunuchs do not become bald, because they change into the female
condition. And as to the hair that comes later in life, eunuchs either do not grow it at all, or lose it if they
happen to have it, with the exception of the pubic hair; for women also grow that though they have not the
other, and this mutilation is a change from the male to the female condition.

The reason why the hair does not grow again in cases of baldness, although both hibernating animals recover
their feathers or hair and trees that have shed their leaves grow leaves again, is this. The seasons of the year
are the turning-points of their lives, rather than their age, so that when these seasons change they change with
them by growing and losing feathers, hairs, or leaves respectively. But the winter and summer, spring and
autumn of man are defined by his age, so that, since his ages do not return, neither do the conditions caused
by them return, although the cause of the change of condition is similar in man to what it is in the animals
and plants in question.

We have now spoken pretty much of all the other conditions of hair.

But as to their colour, it is the nature of the skin that is the cause of this in other animals and also of their
being uni-coloured or vari-coloured); but in man it is not the cause, except of the hair going grey through
disease (not through old age), for in what is called leprosy the hairs become white; on the contrary, if the
hairs are white the whiteness does not invade the skin. The reason is that the hairs grow out of skin; if, then,
the skin is diseased and white the hair becomes diseased with it, and the disease of hair is greyness. But the
greyness of hair which is due to age results from weakness and deficiency of heat. For as the body declines in
vigour we tend to cold at every time of life, and especially in old age, this age being cold and dry. We must
remember that the nutriment coming to each part of the body is concocted by the heat appropriate to the part;
if the heat is inadequate the part loses its efficiency, and destruction or disease results. (We shall speak more
in detail of causes in the treatise on growth and nutrition.) Whenever, then, the hair in man has naturally little
heat and too much moisture enters it, its own proper heat is unable to concoct the moisture and so it is
decayed by the heat in the environing air. All decay is caused by heat, not the innate heat but external heat, as
has been stated elsewhere. And as there is a decay of water, of earth, and all such material bodies, so there is
also of the earthy vapour, for instance what is called mould (for mould is a decay of earthy vapour). Thus also
the liquid nutriment in the hair decays because it is not concocted, and what is called greyness results. It is
white because mould also, practically alone among decayed things, is white. The reason of this is that it has
much air in it, all earthy vapour being equivalent to thick air. For mould is, as it were, the antithesis of
hoar-frost; if the ascending vapour be frozen it becomes hoar-frost, if it be decayed, mould. Hence both are
on the surface of things, for vapour is superficial. And so the comic poets make a good metaphor in jest when
they call grey hairs 'mould of old age' and For the one is generically the same as greyness, the other
specifically; hoar-frost generically (for both are a vapour), mould specifically (for both are a form of decay).
A proof that this is so is this: grey hairs have often grown on men in consequence of disease, and later on
dark hairs instead of them after restoration to health. The reason is that in sickness the whole body is deficient
in natural heat and so the parts besides, even the very small ones, participate in this weakness; and again,
much residual matter is formed in the body and all its parts in illness, wherefore the incapacity in the flesh to
concoct the nutriment causes the grey hairs. But when men have recovered health and strength again they
change, becoming as it were young again instead of old; in consequence the states change also. Indeed, we
may rightly call disease an acquired old age, old age a natural disease; at any rate, some diseases produce the
same effects as old age.

Men go grey on the temples first, because the back of the head is empty of moisture owing to its containing
4 78

ON THE GENERATION OF ANIMALS

no brain, and the 'bregma' has a great deal of moisture, a large quantity not being liable to decay; the hair on
the temples however has neither so little that it can concoct it nor so much that it cannot decay, for this region
of the head being between the two extremes is exempt from both states. The cause of greyness in man has
now been stated.

The reason why this change does not take place visibly on account of age in other animals is the same as that
already given in the case of baldness; their brain is small and less fluid than in man, so that the heat required
for concoction does not altogether fail. Among them it is most clear in horses of all animals that we know,
because the bone about the brain is thinner in them than in others in proportion to their size. A sign of this is
that a blow to this spot is fatal to them, wherefore Homer also has said: 'where the first hairs grow on the
skull of horses, and a wound is most fatal.' As then the moisture easily flows to these hairs because of the
thinness of the bone, whilst the heat fails on account of age, they go grey. The reddish hairs go grey sooner
than the black, redness also being a sort of weakness of hair and all weak things ageing sooner. It is said,
however, that cranes become darker as they grow old. The reason of this would be, if it should prove true,
that their feathers are naturally moister than others and as they grow old the moisture in the feathers is too
much to decay easily.

Greyness comes about by some sort of decay, and is not, as some think, a withering. (1) A proof of the former
statement is the fact that hair protected by hats or other coverings goes grey sooner (for the winds prevent
decay and the protection keeps off the winds), and the fact that it is aided by anointing with a mixture of oil
and water. For, though water cools things, the oil mingled with it prevents the hair from drying quickly, water
being easily dried up. (2) That the process is not a withering, that the hair does not whiten as grass does by
withering, is shown by the fact that some hairs grow grey from the first, whereas nothing springs up in a
withered state. Many hairs also whiten at the tip, for there is least heat in the extremities and thinnest parts.

When the hairs of other animals are white, this is caused by nature, not by any affection. The cause of the
colours in other animals is the skin; if they are white, the skin is white, if they are dark it is dark, if they are
piebald in consequence of a mixture of the hairs, it is found to be white in the one part and dark in the other.
But in man the skin is in no way the cause, for even white-skinned men have very dark hair. The reason is
that man has the thinnest skin of all animals in proportion to his size and therefore it has not strength to
change the hairs; on the contrary the skin itself changes its colour through its weakness and is darkened by
sun and wind, while the hairs do not change along with it at all. But in the other animals the skin, owing to its
thickness, has the influence belonging to the soil in which a thing grows, therefore the hairs change according
to the skin but the skin does not change at all in consequence of the winds and the sun.

Of animals some are uni-coloured (I mean by this term those of which the kind as a whole has one colour, as
all lions are tawny; and this condition exists also in birds, fish, and the other classes of animals alike); others
though many-coloured are yet whole-coloured (I mean those whose body as a whole has the same colour, as
a bull is white as a whole or dark as a whole); others are vari-coloured. This last term is used in both ways;
sometimes the whole kind is vari-coloured, as leopards and peacocks, and some fish, e.g. the so-called
'thrattai'; sometimes the kind as a whole is not so, but such individuals are found in it, as with cattle and goats
and, among birds, pigeons; the same applies also to other kinds of birds. The whole-coloured change much
more than the uniformly coloured, both into the simple colour of another individual of the same kind (as dark
changing into white and vice versa) and into both colours mingled. This is because it is a natural
characteristic of the kind as a whole not to have one colour only, the kind being easily moved in both
directions so that the colours both change more into one another and are more varied. The opposite holds with

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ON THE GENERATION OF ANIMALS

the uniformly coloured; they do not change except by an affection of the colour, and that rarely; but still they
do so change, for before now white individuals have been observed among partridges, ravens, sparrows, and
bears. This happens when the course of development is perverted, for what is small is easily spoilt and easily
moved, and what is developing is small, the beginning of all such things being on a small scale.

Change is especially found in those animals of which by nature the individual is whole-coloured but the kind
many-coloured. This is owing to the water which they drink, for hot waters make the hair white, cold makes
it dark, an effect found also in plants. The reason is that the hot have more air than water in them, and the air
shining through causes whiteness, as also in froth. As, then, skins which are white by reason of some
affection differ from those white by nature, so also in the hair the whiteness due to disease or age differs from
that due to nature in that the cause is different; the latter are whitened by the natural heat, the former by the
external heat. Whiteness is caused in all things by the vaporous air imprisoned in them. Hence also in all
animals not uniformly coloured all the part under the belly is whiter. For practically all white animals are
both hotter and better flavoured for the same reason; the concoction of their nutriment makes them
well-flavoured, and heat causes the concoction. The same cause holds for those animals which are
uniformly-coloured, but either dark or white; heat and cold are the causes of the nature of the skin and hair,
each of the parts having its own special heat.

The tongue also varies in colour in the simply coloured as compared with the vari-coloured animals, and
again in the simply coloured which differ from one another, as white and dark. The reason is that assigned
before, that the skins of the vari-coloured are vari-coloured, and the skins of the white-haired and
dark-haired are white and dark in each case. Now we must conceive of the tongue as one of the external
parts, not taking into account the fact that it is covered by the mouth but looking on it as we do on the hand or
foot; thus since the skin of the vari-coloured animals is not uniformly coloured, this is the cause of the skin
on the tongue being also vari-coloured.

Some birds and some wild quadrupeds change their colour according to the seasons of the year. The reason is
that, as men change according to their age, so the same thing happens to them according to the season; for
this makes a greater difference to them than the change of age.

The more omnivorous animals are more vari-coloured to speak generally, and this is what might be
expected; thus bees are more uniformly coloured than hornets and wasps. For if the food is responsible for the
change we should expect varied food to increase the variety in the movements which cause the development
and so in the residual matter of the food, from which come into being hairs and feathers and skins.

So much for colours and hairs.

As to the voice, it is deep in some animals, high in others, in others again well-pitched and in due proportion
between both extremes. Again, in some it is loud, in others small, and it differs in smoothness and roughness,
flexibility and inflexibility. We must inquire then into the causes of each of these distinctions.

We must suppose then that the same cause is responsible for high and deep voices as for the change which
they undergo in passing from youth to age. The voice is higher in all other animals when younger, but in
cattle that of calves is deeper. We find the same thing also in the male and female sexes; in the other kinds of
animals the voice of the female is higher than that of the male (this being especially plain in man, for Nature
has given this faculty to him in the highest degree because he alone of animals makes use of speech and the
voice is the material of speech), but in cattle the opposite obtains, for the voice of cows is deeper than that of
bulls.

ON THE GENERATION OF ANIMALS

Now the purpose for which animals have a voice, and what is meant by 'voice' and by 'sound' generally, has
been stated partly in the treatise on sensation, partly in that on the soul. But since lowness of voice depends
on the movement of the air being slow and its highness on its being quick, there is a difficulty in knowing
whether it is that which moves or that which is moved that is the cause of the slowness or quickness. For
some say that what is much is moved slowly, what is little quickly, and that the quantity of the air is the cause
of some animals having a deep and others a high voice. Up to a certain point this is well said (for it seems to
be rightly said in a general way that the depth depends on a certain amount of the air put in motion), but not
altogether, for if this were true it would not be easy to speak both soft and deep at once, nor again both loud
and high. Again, the depth seems to belong to the nobler nature, and in songs the deep note is better than the
high-pitched ones, the better lying in superiority, and depth of tone being a sort of superiority. But then depth
and height in the voice are different from loudness and softness, and some high-voiced animals are
loud-voiced, and in like manner some soft-voiced ones are deep-voiced, and the same applies to the tones
lying between these extremes. And by what else can we define these (I mean loudness and softness of voice)
except by the large and small amount of the air put in motion? If then height and depth are to be decided in
accordance with the distinction postulated, the result will be that the same animals will be deep-and
loud-voiced, and the same will be high-and not loud-voiced; but this is false.

The reason of the difficulty is that the words 'great' and 'small', 'much' and 'little' are used sometimes
absolutely, sometimes relatively to one another. Whether an animal has a great (or loud) voice depends on the
air which is moved being much absolutely, whether it has a small voice depends on its being little absolutely;
but whether they have a deep or high voice depends on their being thus differentiated in relation to one
another. For if that which is moved surpass the strength of that which moves it, the air that is sent forth must
go slowly; if the opposite, quickly. The strong, then, on account of their strength, sometimes move much air
and make the movement slow, sometimes, having complete command over it, make the movement swift. On
the same principle the weak either move too much air for their strength and so make the movement slow, or if
they make it swift move but little because of their weakness.

These, then, are the reasons of these contrarieties, that neither are all young animals high-voiced nor all
deep-voiced, nor are all the older, nor yet are the two sexes thus opposed, and again that not only the sick
speak in a high voice but also those in good bodily condition, and, further, that as men verge on old age they
become higher-voiced, though this age is opposite to that of youth.

Most young animals, then, and most females set but little air in motion because of their want of power, and
are consequently high-voiced, for a little air is carried along quickly, and in the voice what is quick is high.
But in calves and cows, in the one case because of their age, in the other because of their female nature, the
part by which they set the air in motion is not strong; at the same time they set a great quantity in motion and
so are deep-voiced; for that which is borne along slowly is heavy, and much air is borne along slowly. And
these animals set much in movement whereas the others set but little, because the vessel through which the
breath is first borne has in them a large opening and necessarily sets much air in motion, whereas in the rest
the air is better dispensed. As their age advances this part which moves the air gains more strength in each
animal, so that they change into the opposite condition, the high-voiced becoming deeper-voiced than they
were, and the deep-voiced higher-voiced, which is why bulls have a higher voice than calves and cows. Now
the strength of all animals is in their sinews, and so those in the prime of life are stronger, the young being
weaker in the joints and sinews; moreover, in the young they are not yet tense, and in those now growing old
the tension relaxes, wherefore both these ages are weak and powerless for movement. And bulls are
particularly sinewy, even their hearts, and therefore that part by which they set the air in motion is in a tense
state, like a sinewy string stretched tight. (That the heart of bulls is of such a nature is shown by the fact that a
bone is actually found in some of them, and bones are naturally connected with sinew.)

All animals when castrated change to the female character, and utter a voice like that of the females because
the sinewy strength in the principle of the voice is relaxed. This relaxation is just as if one should stretch a

7 81

ON THE GENERATION OF ANIMALS

string and make it taut by hanging some weight on to it, as women do who weave at the loom, for they stretch
the warp by attaching to it what are called 'laiai'. For in this way are the testes attached to the seminal
passages, and these again to the blood-vessel which takes its origin in the heart near the organ which sets the
voice in motion. Hence as the seminal passages change towards the age at which they are now able to secrete
the semen, this part also changes along with them. As this changes, the voice again changes, more indeed in
males, but the same thing happens in females too, only not so plainly, the result being what some call
'bleating' when the voice is uneven. After this it settles into the deep or high voice of the succeeding time of
life. If the testes are removed the tension of the passages relaxes, as when the weight is taken off the string or
the warp; as this relaxes, the organ which moves the voice is loosened in the same proportion. This, then, is
the reason why the voice and the form generally changes to the female character in castrated animals; it is
because the principle is relaxed upon which depends the tension of the body; not that, as some suppose, the
testes are themselves a ganglion of many principles, but small changes are the causes of great ones, not per se
but when it happens that a principle changes with them. For the principles, though small in size, are great in
potency; this, indeed, is what is meant by a principle, that it is itself the cause of many things without
anything else being higher than it for it to depend upon.

The heat or cold also of their habitat contributes to make some animals of such a character as to be
deep-voiced, and others high-voiced. For hot breath being thick causes depth, cold breath being thin the
opposite. This is clear also in pipe-playing, for if the breath of the performer is hotter, that is to say if it is
expelled as by a groan, the note is deeper.

The cause of roughness and smoothness in the voice, and of all similar inequality, is that the part or organ
through which the voice is conveyed is rough or smooth or generally even or uneven. This is plain when there
is any moisture about the trachea or when it is roughened by any affection, for then the voice also becomes
uneven.

Flexibility depends on the softness or hardness of the organ, for what is soft can be regulated and assume any
form, while what is hard cannot; thus the soft organ can utter a loud or a small note, and accordingly a high or
a deep one, since it easily regulates the breath, becoming itself easily great or small. But hardness cannot be
regulated.

Let this be enough on all those points concerning the voice which have not been previously discussed in the
treatise on sensation and in that on the soul.

With regard to the teeth it has been stated previously that they do not exist for a single purpose nor for the
same purpose in all animals, but in some for nutrition only, in others also for fighting and for vocal speech.
We must, however, consider it not alien to the discussion of generation and development to inquire into the
reason why the front teeth are formed first and the grinders later, and why the latter are not shed but the
former are shed and grow again.

Democritus has spoken of these questions but not well, for he assigns the cause too generally without
investigating the facts in all cases. He says that the early teeth are shed because they are formed in animals
too early, for it is when animals are practically in their prime that they grow according to Nature, and
suckling is the cause he assigns for their being found too early. Yet the pig also suckles but does not shed its
teeth, and, further, all the animals with carnivorous dentition suckle, but some of them do not shed any teeth
except the canines, e.g. lions. This mistake, then, was due to his speaking generally without examining what
happens in all cases; but this is what we to do, for any one who makes any general statement must speak of
all the particular cases.

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ON THE GENERATION OF ANIMALS

Now we assume, basing our assumption upon what we see, that Nature never fails nor does anything in vain
so far as is possible in each case. And it is necessary, if an animal is to obtain food after the time of taking
milk is over, that it should have instruments for the treatment of the food. If, then, as Democritus says, this
happened about the time of reaching maturity, Nature would fail in something possible for her to do. And,
besides, the operation of Nature would be contrary to Nature, for what is done by violence is contrary to
Nature, and it is by violence that he says the formation of the first teeth is brought about. That this view then
is not true is plain from these and other similar considerations.

Now these teeth are developed before the flat teeth, in the first place because their function is earlier (for
dividing comes before crushing, and the flat teeth are for crushing, the others for dividing), in the second
place because the smaller is naturally developed quicker than the larger, even if both start together, and these
teeth are smaller in size than the grinders, because the bone of the jaw is flat in that part but narrow towards
the mouth. From the greater part, therefore, must flow more nutriment to form the teeth, and from the
narrower part less.

The act of sucking in itself contributes nothing to the formation of the teeth, but the heat of the milk makes
them appear more quickly. A proof of this is that even in suckling animals those young which enjoy hotter
milk grow their teeth quicker, heat being conducive to growth.

They are shed, after they have been formed, partly because it is better so (for what is sharp is soon blunted, so
that a fresh relay is needed for the work, whereas the flat teeth cannot be blunted but are only smoothed in
time by wearing down), partly from necessity because, while the roots of the grinders are fixed where the jaw
is flat and the bone strong, those of the front teeth are in a thin part, so that they are weak and easily moved.
They grow again because they are shed while the bone is still growing and the animal is still young enough to
grow teeth. A proof of this is that even the flat teeth grow for a long time, the last of them cutting the gum at
about twenty years of age; indeed in some cases the last teeth have been grown in quite old age. This is
because there is much nutriment in the broad part of the bones, whereas the front part being thin soon reaches
perfection and no residual matter is found in it, the nutriment being consumed in its own growth.

Democritus, however, neglecting the final cause, reduces to necessity all the operations of Nature. Now they
are necessary, it is true, but yet they are for a final cause and for the sake of what is best in each case. Thus
nothing prevents the teeth from being formed and being shed in this way; but it is not on account of these
causes but on account of the end (or final cause); these are causes only in the sense of being the moving and
efficient instruments and the material. So it is reasonable that Nature should perform most of her operations
using breath as an instrument, for as some instruments serve many uses in the arts, e.g. the hammer and anvil
in the smith's art, so does breath in the living things formed by Nature. But to say that necessity is the only
cause is much as if we should think that the water has been drawn off from a dropsical patient on account of
the lancet, not on account of health, for the sake of which the lancet made the incision.

We have thus spoken of the teeth, saying why some are shed and grow again, and others not, and generally
for what cause they are formed. And we have spoken of the other affections of the parts which are found to
occur not for any final end but of necessity and on account of the motive or efficient cause.

-THE END-

HISTORY OF ANIMALS

by Aristotle

HISTORY OF ANIMALS

Table of Contents

HISTORY OF ANIMALS 1

by Aristotle 1

Book 1 6

_1 6

2 9

_3 10

A 10

_5 10

_6 12

2 13

_8 13

_9 14

10 14

11 14

V2 16

13 16

14 16

15 17

16 18

11 19

Book II . 21

1 21

2 26

1 26

A 26

_5 26

_6 26

1_ 27

_8 27

_9 27

10 28

11 28

12 29

13 30

14 31

15 31

16 32

17 33

Book III 35

1 35

2 38

1 39

A 41

1 43

_6 43

1_ 44

_8 45

9 45

HISTORY OF ANIMALS

Table of Contents

10 45

11 46

V2 47

13 48

14 48

15 48

16 49

17 49

18 49

19 50

10 51

11 52

22 53

Book IV 53

1 53

1 55

1 58

1 61

_6 61

1 62

1 64

1 66

10 68

11 69

Book V. 70

1 70

1 71

1 72

_6 73

1 73

1 74

10 75

11 75

12 76

13 76

14 77

15 79

16 81

17 82

18 83

19 84

20 86

11 87

22 87

HISTORY OF ANIMALS

Table of Contents

13 89

14 89

15 89

16 89

TL 89

18 90

19 90

JO 90

31 91

M 92

33 92

3A 93

Book VI 93

_1 93

2 94

3 95

A 97

3 97

_6 98

1 98

3 99

_9 99

10 99

H 101

12 101

J3 102

U 103

15 104

16 105

H 106

18 107

19 109

20 110

H Ill

12 Ill

23 113

14 113

15 114

16 114

2J 114

18 114

19 115

JO 115

11 116

12 116

J3 116

14 116

35 117

HISTORY OF ANIMALS

Table of Contents

.36 117

31 117

Book VII 118

_1 118

2 119

_3 120

A 121

_5 123

6 123

1_ 124

_8 124

_9 125

10 125

11 126

V2 126

Book VIII 127

_1 127

2 128

1 131

A 133

_5 133

6 134

1_ 134

_8 135

9. 135

10 135

11 136

12 136

13 137

14 139

15 139

16 140

11 140

18 141

19 141

20 143

H 143

22 144

23 144

24 144

15 145

26 145

17 145

18 146

19 147

10 147

Book IX 148

1 148

HISTORY OF ANIMALS

Table of Contents

1 151

A 152

_5 152

_6 153

1 154

_8 154

_9 155

10 156

H 156

V2 156

V3 157

14 157

15 158

16 158

H 158

18 158

19 158

10 159

21 159

22 159

23 159

14 159

15 159

16 160

21 160

18 160

19 160

10 160

11 161

12 161

13 162

14 162

15 162

16 162

21 163

18 165

19 165

40 166

H 170

42 171

43 172

44 172

45 173

46 173

17 173

18 174

49 174

HISTORY OF ANIMALS

Table of Contents

.50 174

49R 175

HISTORY OF ANIMALS

by Aristotle

translated by D'Arcy Wentworth Thompson

« Book I

12
« Book II

12
13
14
15
16
12
« Book III

HISTORY OF ANIMALS

21
22
« Book IV

1
2
3
4
5
6
7
8
9

1Q
U
« Book V

12
12
11
12
16

12
18

HISTORY OF ANIMALS

21
22
23
24
25
26
27
28
29
30
31
32
33
34
« Book VI

1
2
3
4
5
6
7
8
9
10

12
13
H

15
16

12
18
12
20
21
22
22
24
25
26
27
28
22
30
31
22
33
34

HISTORY OF ANIMALS

•35
•36

• 37

• Book VII

• 1

• 2
•3
•4
•5
•6
•7
•8
•9

• 10
•li
•12

• Book VIII

• 1
•2
•3
•4
•5
•6
•7
•8
•9

• 10

•u

•12
•13
•14
•15

• 16
•12

•18
•19

• 20

•21

• 22

• 23

• 24
•25.

• 26

• 27

• 28

• 29
•30

• Book IX

• 1

• 2
•3

HISTORY OF ANIMALS

22
24
25
26
27
28
22
30
31
22
33
M
35
36
37
38
39
40
11
42
43
44
45
46
47
48
49
50
49B

HISTORY OF ANIMALS

Book I

OF the parts of animals some are simple: to wit, all such as divide into parts uniform with themselves, as
flesh into flesh; others are composite, such as divide into parts not uniform with themselves, as, for instance,
the hand does not divide into hands nor the face into faces.

And of such as these, some are called not parts merely, but limbs or members. Such are those parts that, while
entire in themselves, have within themselves other diverse parts: as for instance, the head, foot, hand, the arm
as a whole, the chest; for these are all in themselves entire parts, and there are other diverse parts belonging to
them.

All those parts that do not subdivide into parts uniform with themselves are composed of parts that do so
subdivide, for instance, hand is composed of flesh, sinews, and bones. Of animals, some resemble one
another in all their parts, while others have parts wherein they differ. Sometimes the parts are identical in
form or species, as, for instance, one man's nose or eye resembles another man's nose or eye, flesh flesh, and
bone bone; and in like manner with a horse, and with all other animals which we reckon to be of one and the
same species: for as the whole is to the whole, so each to each are the parts severally. In other cases the parts
are identical, save only for a difference in the way of excess or defect, as is the case in such animals as are of
one and the same genus. By 'genus' I mean, for instance, Bird or Fish, for each of these is subject to
difference in respect of its genus, and there are many species of fishes and of birds.

Within the limits of genera, most of the parts as a rule exhibit differences through contrast of the property or
accident, such as colour and shape, to which they are subject: in that some are more and some in a less degree
the subject of the same property or accident; and also in the way of multitude or fewness, magnitude or
parvitude, in short in the way of excess or defect. Thus in some the texture of the flesh is soft, in others firm;
some have a long bill, others a short one; some have abundance of feathers, others have only a small quantity.
It happens further that some have parts that others have not: for instance, some have spurs and others not,
some have crests and others not; but as a general rule, most parts and those that go to make up the bulk of the
body are either identical with one another, or differ from one another in the way of contrast and of excess and
defect. For 'the more' and 'the less' may be represented as 'excess' or 'defect'.

Once again, we may have to do with animals whose parts are neither identical in form nor yet identical save
for differences in the way of excess or defect: but they are the same only in the way of analogy, as, for
instance, bone is only analogous to fish-bone, nail to hoof, hand to claw, and scale to feather; for what the
feather is in a bird, the scale is in a fish.

The parts, then, which animals severally possess are diverse from, or identical with, one another in the
fashion above described. And they are so furthermore in the way of local disposition: for many animals have
identical organs that differ in position; for instance, some have teats in the breast, others close to the thighs.

Of the substances that are composed of parts uniform (or homogeneous) with themselves, some are soft and
moist, others are dry and solid. The soft and moist are such either absolutely or so long as they are in their
natural conditions, as, for instance, blood, serum, lard, suet, marrow, sperm, gall, milk in such as have it flesh
and the like; and also, in a different way, the superfluities, as phlegm and the excretions of the belly and the
bladder. The dry and solid are such as sinew, skin, vein, hair, bone, gristle, nail, horn (a term which as
applied to the part involves an ambiguity, since the whole also by virtue of its form is designated horn), and
such parts as present an analogy to these.

Book I

HISTORY OF ANIMALS

Animals differ from one another in their modes of subsistence, in their actions, in their habits, and in their
parts. Concerning these differences we shall first speak in broad and general terms, and subsequently we shall
treat of the same with close reference to each particular genus.

Differences are manifested in modes of subsistence, in habits, in actions performed. For instance, some
animals live in water and others on land. And of those that live in water some do so in one way, and some in
another: that is to say, some live and feed in the water, take in and emit water, and cannot live if deprived of
water, as is the case with the great majority of fishes; others get their food and spend their days in the water,
but do not take in water but air, nor do they bring forth in the water. Many of these creatures are furnished
with feet, as the otter, the beaver, and the crocodile; some are furnished with wings, as the diver and the
grebe; some are destitute of feet, as the water-snake. Some creatures get their living in the water and cannot
exist outside it: but for all that do not take in either air or water, as, for instance, the sea-nettle and the oyster.
And of creatures that live in the water some live in the sea, some in rivers, some in lakes, and some in
marshes, as the frog and the newt.

Of animals that live on dry land some take in air and emit it, which phenomena are termed 'inhalation' and
'exhalation'; as, for instance, man and all such land animals as are furnished with lungs. Others, again, do not
inhale air, yet live and find their sustenance on dry land; as, for instance, the wasp, the bee, and all other
insects. And by 'insects' I mean such creatures as have nicks or notches on their bodies, either on their bellies
or on both backs and bellies.

And of land animals many, as has been said, derive their subsistence from the water; but of creatures that live
in and inhale water not a single one derives its subsistence from dry land.

Some animals at first live in water, and by and by change their shape and live out of water, as is the case with
river worms, for out of these the gadfly develops.

Furthermore, some animals are stationary, and some are erratic. Stationary animals are found in water, but no
such creature is found on dry land. In the water are many creatures that live in close adhesion to an external
object, as is the case with several kinds of oyster. And, by the way, the sponge appears to be endowed with a
certain sensibility: as a proof of which it is alleged that the difficulty in detaching it from its moorings is
increased if the movement to detach it be not covertly applied.

Other creatures adhere at one time to an object and detach themselves from it at other times, as is the case
with a species of the so-called sea-nettle; for some of these creatures seek their food in the night-time loose
and unattached.

Many creatures are unattached but motionless, as is the case with oysters and the so-called holothuria. Some
can swim, as, for instance, fishes, molluscs, and crustaceans, such as the crawfish. But some of these last
move by walking, as the crab, for it is the nature of the creature, though it lives in water, to move by walking.

Of land animals some are furnished with wings, such as birds and bees, and these are so furnished in different
ways one from another; others are furnished with feet. Of the animals that are furnished with feet some walk,
some creep, and some wriggle. But no creature is able only to move by flying, as the fish is able only to
swim, for the animals with leathern wings can walk; the bat has feet and the seal has imperfect feet.

Some birds have feet of little power, and are therefore called Apodes. This little bird is powerful on the wing;
and, as a rule, birds that resemble it are weak-footed and strong winged, such as the swallow and the
drepanis or (?) Alpine swift; for all these birds resemble one another in their habits and in their plumage, and
may easily be mistaken one for another. (The apus is to be seen at all seasons, but the drepanis only after
rainy weather in summer; for this is the time when it is seen and captured, though, as a general rule, it is a

Book I 7

HISTORY OF ANIMALS

rare bird.)

Again, some animals move by walking on the ground as well as by swimming in water.

Furthermore, the following differences are manifest in their modes of living and in their actions. Some are
gregarious, some are solitary, whether they be furnished with feet or wings or be fitted for a life in the water;
and some partake of both characters, the solitary and the gregarious. And of the gregarious, some are
disposed to combine for social purposes, others to live each for its own self.

Gregarious creatures are, among birds, such as the pigeon, the crane, and the swan; and, by the way, no bird
furnished with crooked talons is gregarious. Of creatures that live in water many kinds of fishes are
gregarious, such as the so-called migrants, the tunny, the pelamys, and the bonito.

Man, by the way, presents a mixture of the two characters, the gregarious and the solitary.

Social creatures are such as have some one common object in view; and this property is not common to all
creatures that are gregarious. Such social creatures are man, the bee, the wasp, the ant, and the crane.

Again, of these social creatures some submit to a ruler, others are subject to no governance: as, for instance,
the crane and the several sorts of bee submit to a ruler, whereas ants and numerous other creatures are every
one his own master.

And again, both of gregarious and of solitary animals, some are attached to a fixed home and others are
erratic or nomad.

Also, some are carnivorous, some graminivorous, some omnivorous: whilst some feed on a peculiar diet, as
for instance the bees and the spiders, for the bee lives on honey and certain other sweets, and the spider lives
by catching flies; and some creatures live on fish. Again, some creatures catch their food, others treasure it
up; whereas others do not so.

Some creatures provide themselves with a dwelling, others go without one: of the former kind are the mole,
the mouse, the ant, the bee; of the latter kind are many insects and quadrupeds. Further, in respect to locality
of dwelling place, some creatures dwell under ground, as the lizard and the snake; others live on the surface
of the ground, as the horse and the dog. make to themselves holes, others do not

Some are nocturnal, as the owl and the bat; others live in the daylight.

Moreover, some creatures are tame and some are wild: some are at all times tame, as man and the mule;
others are at all times savage, as the leopard and the wolf; and some creatures can be rapidly tamed, as the
elephant.

Again, we may regard animals in another light. For, whenever a race of animals is found domesticated, the
same is always to be found in a wild condition; as we find to be the case with horses, kine, swine, (men),
sheep, goats, and dogs.

Further, some animals emit sound while others are mute, and some are endowed with voice: of these latter
some have articulate speech, while others are inarticulate; some are given to continual chirping and twittering
some are prone to silence; some are musical, and some unmusical; but all animals without exception exercise
their power of singing or chattering chiefly in connexion with the intercourse of the sexes.

Book I

HISTORY OF ANIMALS

Again, some creatures live in the fields, as the cushat; some on the mountains, as the hoopoe; some frequent
the abodes of men, as the pigeon.

Some, again, are peculiarly salacious, as the partridge, the barn-door cock and their congeners; others are
inclined to chastity, as the whole tribe of crows, for birds of this kind indulge but rarely in sexual intercourse.

Of marine animals, again, some live in the open seas, some near the shore, some on rocks.

Furthermore, some are combative under offence; others are provident for defence. Of the former kind are
such as act as aggressors upon others or retaliate when subjected to ill usage, and of the latter kind are such as
merely have some means of guarding themselves against attack.

Animals also differ from one another in regard to character in the following respects. Some are
good-tempered, sluggish, and little prone to ferocity, as the ox; others are quick tempered, ferocious and
unteachable, as the wild boar; some are intelligent and timid, as the stag and the hare; others are mean and
treacherous, as the snake; others are noble and courageous and high-bred, as the lion; others are
thorough-bred and wild and treacherous, as the wolf: for, by the way, an animal is highbred if it come from a
noble stock, and an animal is thorough-bred if it does not deflect from its racial characteristics.

Further, some are crafty and mischievous, as the fox; some are spirited and affectionate and fawning, as the
dog; others are easy-tempered and easily domesticated, as the elephant; others are cautious and watchful, as
the goose; others are jealous and self-conceited, as the peacock. But of all animals man alone is capable of
deliberation.

Many animals have memory, and are capable of instruction; but no other creature except man can recall the
past at will.

With regard to the several genera of animals, particulars as to their habits of life and modes of existence will
be discussed more fully by and by.

Common to all animals are the organs whereby they take food and the organs where into they take it; and
these are either identical with one another, or are diverse in the ways above specified: to wit, either identical
in form, or varying in respect of excess or defect, or resembling one another analogically, or differing in
position.

Furthermore, the great majority of animals have other organs besides these in common, whereby they
discharge the residuum of their food: I say, the great majority, for this statement does not apply to all. And,
by the way, the organ whereby food is taken in is called the mouth, and the organ whereinto it is taken, the
belly; the remainder of the alimentary system has a great variety of names.

Now the residuum of food is twofold in kind, wet and dry, and such creatures as have organs receptive of wet
residuum are invariably found with organs receptive of dry residuum; but such as have organs receptive of
dry residuum need not possess organs receptive of wet residuum. In other words, an animal has a bowel or
intestine if it have a bladder; but an animal may have a bowel and be without a bladder. And, by the way, I
may here remark that the organ receptive of wet residuum is termed 'bladder', and the organ receptive of dry
residuum 'intestine or 'bowel'.

HISTORY OF ANIMALS

Of animals otherwise, a great many have, besides the organs above-mentioned, an organ for excretion of the
sperm: and of animals capable of generation one secretes into another, and the other into itself. The latter is
termed 'female', and the former 'male'; but some animals have neither male nor female. Consequently, the
organs connected with this function differ in form, for some animals have a womb and others an organ
analogous thereto. The above-mentioned organs, then, are the most indispensable parts of animals; and with
some of them all animals without exception, and with others animals for the most part, must needs be
provided.

One sense, and one alone, is common to all animals-the sense of touch. Consequently, there is no special
name for the organ in which it has its seat; for in some groups of animals the organ is identical, in others it is
only analogous.

Every animal is supplied with moisture, and, if the animal be deprived of the same by natural causes or
artificial means, death ensues: further, every animal has another part in which the moisture is contained.
These parts are blood and vein, and in other animals there is something to correspond; but in these latter the
parts are imperfect, being merely fibre and serum or lymph.

Touch has its seat in a part uniform and homogeneous, as in the flesh or something of the kind, and generally,
with animals supplied with blood, in the parts charged with blood. In other animals it has its seat in parts
analogous to the parts charged with blood; but in all cases it is seated in parts that in their texture are
homogeneous.

The active faculties, on the contrary, are seated in the parts that are heterogeneous: as, for instance, the
business of preparing the food is seated in the mouth, and the office of locomotion in the feet, the wings, or in
organs to correspond.

Again, some animals are supplied with blood, as man, the horse, and all such animals as are, when
full-grown, either destitute of feet, or two-footed, or four-footed; other animals are bloodless, such as the
bee and the wasp, and, of marine animals, the cuttle-fish, the crawfish, and all such animals as have more
than four feet.

Again, some animals are viviparous, others oviparous, others vermiparous or 'grub-bearing'. Some are
viviparous, such as man, the horse, the seal, and all other animals that are hair-coated, and, of marine
animals, the cetaceans, as the dolphin, and the so-called Selachia. (Of these latter animals, some have a
tubular air-passage and no gills, as the dolphin and the whale: the dolphin with the air-passage going
through its back, the whale with the air-passage in its forehead; others have uncovered gills, as the Selachia,
the sharks and rays.)

What we term an egg is a certain completed result of conception out of which the animal that is to be
develops, and in such a way that in respect to its primitive germ it comes from part only of the egg, while the
rest serves for food as the germ develops. A 'grub' on the other hand is a thing out of which in its entirety the
animal in its entirety develops, by differentiation and growth of the embryo.

HISTORY OF ANIMALS

Of viviparous animals, some hatch eggs in their own interior, as creatures of the shark kind; others engender
in their interior a live foetus, as man and the horse. When the result of conception is perfected, with some
animals a living creature is brought forth, with others an egg is brought to light, with others a grub. Of the
eggs, some have egg-shells and are of two different colours within, such as birds' eggs; others are
soft-skinned and of uniform colour, as the eggs of animals of the shark kind. Of the grubs, some are from the
first capable of movement, others are motionless. However, with regard to these phenomena we shall speak
precisely hereafter when we come to treat of Generation.

Furthermore, some animals have feet and some are destitute thereof. Of such as have feet some animals have
two, as is the case with men and birds, and with men and birds only; some have four, as the lizard and the
dog; some have more, as the centipede and the bee; but allsoever that have feet have an even number of them.

Of swimming creatures that are destitute of feet, some have winglets or fins, as fishes: and of these some
have four fins, two above on the back, two below on the belly, as the gilthead and the basse; some have two
only,-to wit, such as are exceedingly long and smooth, as the eel and the conger; some have none at all, as
the muraena, but use the sea just as snakes use dry ground-and by the way, snakes swim in water in just the
same way. Of the shark-kind some have no fins, such as those that are flat and long-tailed, as the ray and the
sting-ray, but these fishes swim actually by the undulatory motion of their flat bodies; the fishing frog,
however, has fins, and so likewise have all such fishes as have not their flat surfaces thinned off to a sharp
edge.

Of those swimming creatures that appear to have feet, as is the case with the molluscs, these creatures swim
by the aid of their feet and their fins as well, and they swim most rapidly backwards in the direction of the
trunk, as is the case with the cuttle-fish or sepia and the calamary; and, by the way, neither of these latter can
walk as the poulpe or octopus can.

The hard-skinned or crustaceous animals, like the crawfish, swim by the instrumentality of their tail-parts;
and they swim most rapidly tail foremost, by the aid of the fins developed upon that member. The newt
swims by means of its feet and tail; and its tail resembles that of the sheatfish, to compare little with great.

Of animals that can fly some are furnished with feathered wings, as the eagle and the hawk; some are
furnished with membranous wings, as the bee and the cockchafer; others are furnished with leathern wings,
as the flying fox and the bat. All flying creatures possessed of blood have feathered wings or leathern wings;
the bloodless creatures have membranous wings, as insects. The creatures that have feathered wings or
leathern wings have either two feet or no feet at all: for there are said to be certain flying serpents in Ethiopia
that are destitute of feet.

Creatures that have feathered wings are classed as a genus under the name of 'bird'; the other two genera, the
leathern-winged and membrane-winged, are as yet without a generic title.

Of creatures that can fly and are bloodless some are coleopterous or sheath-winged, for they have their wings
in a sheath or shard, like the cockchafer and the dung-beetle; others are sheathless, and of these latter some
are dipterous and some tetrapterous: tetrapterous, such as are comparatively large or have their stings in the
tail, dipterous, such as are comparatively small or have their stings in front. The coleoptera are, without
exception, devoid of stings; the diptera have the sting in front, as the fly, the horsefly, the gadfly, and the
gnat.

Bloodless animals as a general rule are inferior in point of size to blooded animals; though, by the way, there
are found in the sea some few bloodless creatures of abnormal size, as in the case of certain molluscs. And of
these bloodless genera, those are the largest that dwell in milder climates, and those that inhabit the sea are
larger than those living on dry land or in fresh water.

3 11

HISTORY OF ANIMALS

All creatures that are capable of motion move with four or more points of motion; the blooded animals with
four only: as, for instance, man with two hands and two feet, birds with two wings and two feet, quadrupeds
and fishes severally with four feet and four fins. Creatures that have two winglets or fins, or that have none at
all like serpents, move all the same with not less than four points of motion; for there are four bends in their
bodies as they move, or two bends together with their fins. Bloodless and many footed animals, whether
furnished with wings or feet, move with more than four points of motion; as, for instance, the dayfly moves
with four feet and four wings: and, I may observe in passing, this creature is exceptional not only in regard to
the duration of its existence, whence it receives its name, but also because though a quadruped it has wings
also.

All animals move alike, four-footed and many-footed; in other words, they all move cross-corner-wise.
And animals in general have two feet in advance; the crab alone has four.

Very extensive genera of animals, into which other subdivisions fall, are the following: one, of birds; one, of
fishes; and another, of cetaceans. Now all these creatures are blooded.

There is another genus of the hard-shell kind, which is called oyster; another of the soft-shell kind, not as yet
designated by a single term, such as the spiny crawfish and the various kinds of crabs and lobsters; and
another of molluscs, as the two kinds of calamary and the cuttle-fish; that of insects is different. All these
latter creatures are bloodless, and such of them as have feet have a goodly number of them; and of the insects
some have wings as well as feet.

Of the other animals the genera are not extensive. For in them one species does not comprehend many
species; but in one case, as man, the species is simple, admitting of no differentiation, while other cases admit
of differentiation, but the forms lack particular designations.

So, for instance, creatures that are qudapedal and unprovided with wings are blooded without exception, but
some of them are viviparous, and some oviparous. Such as are viviparous are hair-coated, and such as are
oviparous are covered with a kind of tessellated hard substance; and the tessellated bits of this substance are,
as it were, similar in regard to position to a scale.

An animal that is blooded and capable of movement on dry land, but is naturally unprovided with feet,
belongs to the serpent genus; and animals of this genus are coated with the tessellated horny substance.
Serpents in general are oviparous; the adder, an exceptional case, is viviparous: for not all viviparous animals
are hair-coated, and some fishes also are viviparous.

All animals, however, that are hair-coated are viviparous. For, by the way, one must regard as a kind of hair
such prickly hairs as hedgehogs and porcupines carry; for these spines perform the office of hair, and not of
feet as is the case with similar parts of sea-urchins.

In the genus that combines all viviparous quadrupeds are many species, but under no common appellation.
They are only named as it were one by one, as we say man, lion, stag, horse, dog, and so on; though, by the
way, there is a sort of genus that embraces all creatures that have bushy manes and bushy tails, such as the
horse, the ass, the mule, the jennet, and the animals that are called Hemioni in Syria,-from their externally
resembling mules, though they are not strictly of the same species. And that they are not so is proved by the
fact that they mate with and breed from one another. For all these reasons, we must take animals species by
species, and discuss their peculiarities severally'

HISTORY OF ANIMALS

These preceding statements, then, have been put forward thus in a general way, as a kind of foretaste of the
number of subjects and of the properties that we have to consider in order that we may first get a clear notion
of distinctive character and common properties. By and by we shall discuss these matters with greater
minuteness.

After this we shall pass on to the discussion of causes. For to do this when the investigation of the details is
complete is the proper and natural method, and that whereby the subjects and the premisses of our argument
will afterwards be rendered plain.

In the first place we must look to the constituent parts of animals. For it is in a way relative to these parts,
first and foremost, that animals in their entirety differ from one another: either in the fact that some have this
or that, while they have not that or this; or by peculiarities of position or of arrangement; or by the differences
that have been previously mentioned, depending upon diversity of form, or excess or defect in this or that
particular, on analogy, or on contrasts of the accidental qualities.

To begin with, we must take into consideration the parts of Man. For, just as each nation is wont to reckon by
that monetary standard with which it is most familiar, so must we do in other matters. And, of course, man is
the animal with which we are all of us the most familiar.

Now the parts are obvious enough to physical perception. However, with the view of observing due order and
sequence and of combining rational notions with physical perception, we shall proceed to enumerate the
parts: firstly, the organic, and afterwards the simple or non-composite.

The chief parts into which the body as a whole is subdivided, are the head, the neck, the trunk (extending
from the neck to the privy parts), which is called the thorax, two arms and two legs.

Of the parts of which the head is composed the hair-covered portion is called the 'skull'. The front portion of
it is termed 'bregma' or 'sinciput', developed after birth-for it is the last of all the bones in the body to acquire
solidity,-the hinder part is termed the 'occiput', and the part intervening between the sinciput and the occiput
is the 'crown'. The brain lies underneath the sinciput; the occiput is hollow. The skull consists entirely of thin
bone, rounded in shape, and contained within a wrapper of fleshless skin.

The skull has sutures: one, of circular form, in the case of women; in the case of men, as a general rule, three
meeting at a point. Instances have been known of a man's skull devoid of suture altogether. In the skull the
middle line, where the hair parts, is called the crown or vertex. In some cases the parting is double; that is to
say, some men are double crowned, not in regard to the bony skull, but in consequence of the double fall or
set of the hair.

The part that lies under the skull is called the 'face': but in the case of man only, for the term is not applied to
a fish or to an ox. In the face the part below the sinciput and between the eyes is termed the forehead. When
men have large foreheads, they are slow to move; when they have small ones, they are fickle; when they have
broad ones, they are apt to be distraught; when they have foreheads rounded or bulging out, they are
quick-tempered.

HISTORY OF ANIMALS

Underneath the forehead are two eyebrows. Straight eyebrows are a sign of softness of disposition; such as
curve in towards the nose, of harshness; such as curve out towards the temples, of humour and dissimulation;
such as are drawn in towards one another, of jealousy.

Under the eyebrows come the eyes. These are naturally two in number. Each of them has an upper and a
lower eyelid, and the hairs on the edges of these are termed 'eyelashes'. The central part of the eye includes
the moist part whereby vision is effected, termed the 'pupil', and the part surrounding it called the 'black'; the
part outside this is the 'white'. A part common to the upper and lower eyelid is a pair of nicks or corners, one
in the direction of the nose, and the other in the direction of the temples. When these are long they are a sign
of bad disposition; if the side toward the nostril be fleshy and comb-like, they are a sign of dishonesty.

All animals, as a general rule, are provided with eyes, excepting the ostracoderms and other imperfect
creatures; at all events, all viviparous animals have eyes, with the exception of the mole. And yet one might
assert that, though the mole has not eyes in the full sense, yet it has eyes in a kind of a way. For in point of
absolute fact it cannot see, and has no eyes visible externally; but when the outer skin is removed, it is found
to have the place where eyes are usually situated, and the black parts of the eyes rightly situated, and all the
place that is usually devoted on the outside to eyes: showing that the parts are stunted in development, and
the skin allowed to grow over.

Of the eye the white is pretty much the same in all creatures; but what is called the black differs in various
animals. Some have the rim black, some distinctly blue, some greyish-blue, some greenish; and this last
colour is the sign of an excellent disposition, and is particularly well adapted for sharpness of vision. Man is
the only, or nearly the only, creature, that has eyes of diverse colours. Animals, as a rule, have eyes of one
colour only. Some horses have blue eyes.

Of eyes, some are large, some small, some medium-sized; of these, the medium-sized are the best.
Moreover, eyes sometimes protrude, sometimes recede, sometimes are neither protruding nor receding. Of
these, the receding eye is in all animals the most acute; but the last kind are the sign of the best disposition.
Again, eyes are sometimes inclined to wink under observation, sometimes to remain open and staring, and
sometimes are disposed neither to wink nor stare. The last kind are the sign of the best nature, and of the
others, the latter kind indicates impudence, and the former indecision.

Furthermore, there is a portion of the head, whereby an animal hears, a part incapable of breathing, the 'ear'. I
say 'incapable of breathing', for Alcmaeon is mistaken when he says that goats inspire through their ears. Of
the ear one part is unnamed, the other part is called the 'lobe'; and it is entirely composed of gristle and flesh.
The ear is constructed internally like the trumpet-shell, and the innermost bone is like the ear itself, and into
it at the end the sound makes its way, as into the bottom of a jar. This receptacle does not communicate by
any passage with the brain, but does so with the palate, and a vein extends from the brain towards it. The eyes
also are connected with the brain, and each of them lies at the end of a little vein. Of animals possessed of
ears man is the only one that cannot move this organ. Of creatures possessed of hearing, some have ears,
whilst others have none, but merely have the passages for ears visible, as, for example, feathered animals or
animals coated with horny tessellates.

HISTORY OF ANIMALS

Viviparous animals, with the exception of the seal, the dolphin, and those others which after a similar fashion
to these are cetaceans, are all provided with ears; for, by the way, the shark-kind are also viviparous. Now,
the seal has the passages visible whereby it hears; but the dolphin can hear, but has no ears, nor yet any
passages visible. But man alone is unable to move his ears, and all other animals can move them. And the
ears lie, with man, in the same horizontal plane with the eyes, and not in a plane above them as is the case
with some quadrupeds. Of ears, some are fine, some are coarse, and some are of medium texture; the last kind
are best for hearing, but they serve in no way to indicate character. Some ears are large, some small, some
medium-sized; again, some stand out far, some lie in close and tight, and some take up a medium position; of
these such as are of medium size and of medium position are indications of the best disposition, while the
large and outstanding ones indicate a tendency to irrelevant talk or chattering. The part intercepted between
the eye, the ear, and the crown is termed the 'temple'. Again, there is a part of the countenance that serves as a
passage for the breath, the 'nose'. For a man inhales and exhales by this organ, and sneezing is effected by its
means: which last is an outward rush of collected breath, and is the only mode of breath used as an omen and
regarded as supernatural. Both inhalation and exhalation go right on from the nose towards the chest; and
with the nostrils alone and separately it is impossible to inhale or exhale, owing to the fact that the inspiration
and respiration take place from the chest along the windpipe, and not by any portion connected with the head;
and indeed it is possible for a creature to live without using this process of nasal respiration.

Again, smelling takes place by means of the nose,-smelling, or the sensible discrimination of odour. And the
nostril admits of easy motion, and is not, like the ear, intrinsically immovable. A part of it, composed of
gristle, constitutes, a septum or partition, and part is an open passage; for the nostril consists of two separate
channels. The nostril (or nose) of the elephant is long and strong, and the animal uses it like a hand; for by
means of this organ it draws objects towards it, and takes hold of them, and introduces its food into its mouth,
whether liquid or dry food, and it is the only living creature that does so.

Furthermore, there are two jaws; the front part of them constitutes the chin, and the hinder part the cheek. All
animals move the lower jaw, with the exception of the river crocodile; this creature moves the upper jaw
only.

Next after the nose come two lips, composed of flesh, and facile of motion. The mouth lies inside the jaws
and lips. Parts of the mouth are the roof or palate and the pharynx.

The part that is sensible of taste is the tongue. The sensation has its seat at the tip of the tongue; if the object
to be tasted be placed on the flat surface of the organ, the taste is less sensibly experienced. The tongue is
sensitive in all other ways wherein flesh in general is so: that is, it can appreciate hardness, or warmth and
cold, in any part of it, just as it can appreciate taste. The tongue is sometimes broad, sometimes narrow, and
sometimes of medium width; the last kind is the best and the clearest in its discrimination of taste. Moreover,
the tongue is sometimes loosely hung, and sometimes fastened: as in the case of those who mumble and who
lisp.

The tongue consists of flesh, soft and spongy, and the so-called 'epiglottis' is a part of this organ.

That part of the mouth that splits into two bits is called the 'tonsils'; that part that splits into many bits, the
'gums'. Both the tonsils and the gums are composed of flesh. In the gums are teeth, composed of bone.

Inside the mouth is another part, shaped like a bunch of grapes, a pillar streaked with veins. If this pillar gets
relaxed and inflamed it is called 'uvula' or 'bunch of grapes', and it then has a tendency to bring about
suffocation.

HISTORY OF ANIMALS

The neck is the part between the face and the trunk. Of this the front part is the larynx land the back part the
ur The front part, composed of gristle, through which respiration and speech is effected, is termed the
'windpipe'; the part that is fleshy is the oesophagus, inside just in front of the chine. The part to the back of
the neck is the epomis, or 'shoulder-point'.

These then are the parts to be met with before you come to the thorax.

To the trunk there is a front part and a back part. Next after the neck in the front part is the chest, with a pair
of breasts. To each of the breasts is attached a teat or nipple, through which in the case of females the milk
percolates; and the breast is of a spongy texture. Milk, by the way, is found at times in the male; but with the
male the flesh of the breast is tough, with the female it is soft and porous.

Next after the thorax and in front comes the 'belly', and its root the 'navel'. Underneath this root the bilateral
part is the 'flank': the undivided part below the navel, the 'abdomen', the extremity of which is the region of
the 'pubes'; above the navel the 'hypochondrium'; the cavity common to the hypochondrium and the flank is
the gut-cavity.

Serving as a brace girdle to the hinder parts is the pelvis, and hence it gets its name (osphus), for it is
symmetrical (isophues) in appearance; of the fundament the part for resting on is termed the 'rump', and the
part whereon the thigh pivots is termed the 'socket' (or acetabulum).

The 'womb' is a part peculiar to the female; and the 'penis' is peculiar to the male. This latter organ is external
and situated at the extremity of the trunk; it is composed of two separate parts: of which the extreme part is
fleshy, does not alter in size, and is called the glans; and round about it is a skin devoid of any specific title,
which integument if it be cut asunder never grows together again, any more than does the jaw or the eyelid.
And the connexion between the latter and the glans is called the frenum. The remaining part of the penis is
composed of gristle; it is easily susceptible of enlargement; and it protrudes and recedes in the reverse
directions to what is observable in the identical organ in cats. Underneath the penis are two 'testicles', and the
integument of these is a skin that is termed the 'scrotum'.

Testicles are not identical with flesh, and are not altogether diverse from it. But by and by we shall treat in an
exhaustive way regarding all such parts.

The privy part of the female is in character opposite to that of the male. In other words, the part under the
pubes is hollow or receding, and not, like the male organ, protruding. Further, there is an 'urethra' outside the
womb; which organ serves as a passage for the sperm of the male, and as an outlet for liquid excretion to both

sexes).

The part common to the neck and chest is the 'throat'; the 'armpit' is common to side, arm, and shoulder; and
the 'groin' is common to thigh and abdomen. The part inside the thigh and buttocks is the 'perineum', and the
part outside the thigh and buttocks is the 'hypoglutis'.

The front parts of the trunk have now been enumerated.

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HISTORY OF ANIMALS
The part behind the chest is termed the 'back'.

Parts of the back are a pair of 'shoulderblades', the 'back-bone', and, underneath on a level with the belly in
the trunk, the 'loins'. Common to the upper and lower part of the trunk are the 'ribs', eight on either side, for as
to the so-called seven-ribbed Ligyans we have not received any trustworthy evidence.

Man, then, has an upper and a lower part, a front and a back part, a right and a left side. Now the right and the
left side are pretty well alike in their parts and identical throughout, except that the left side is the weaker of
the two; but the back parts do not resemble the front ones, neither do the lower ones the upper: only that these
upper and lower parts may be said to resemble one another thus far, that, if the face be plump or meagre, the
abdomen is plump or meagre to correspond; and that the legs correspond to the arms, and where the upper
arm is short the thigh is usually short also, and where the feet are small the hands are small correspondingly.

Of the limbs, one set, forming a pair, is 'arms'. To the arm belong the 'shoulder', 'upper-arm', 'elbow',
'fore-arm', and 'hand'. To the hand belong the 'palm', and the five 'fingers'. The part of the finger that bends is
termed 'knuckle', the part that is inflexible is termed the 'phalanx'. The big finger or thumb is single-jointed,
the other fingers are double jointed. The bending both of the arm and of the finger takes place from without
inwards in all cases; and the arm bends at the elbow. The inner part of the hand is termed the palm', and is
fleshy and divided by joints or lines: in the case of long-lived people by one or two extending right across, in
the case of the short-lived by two, not so extending. The joint between hand and arm is termed the 'wrist'.
The outside or back of the hand is sinewy, and has no specific designation.

There is another duplicate limb, the 'leg'. Of this limb the double-knobbed part is termed the 'thigh-bone', the
sliding part of the 'kneecap', the double-boned part the 'leg'; the front part of this latter is termed the 'shin',
and the part behind it the 'calf, wherein the flesh is sinewy and venous, in some cases drawn upwards
towards the hollow behind the knee, as in the case of people with large hips, and in other cases drawn
downwards. The lower extremity of the shin is the 'ankle', duplicate in either leg. The part of the limb that
contains a multiplicity of bones is the 'foot'. The hinder part of the foot is the 'heel'; at the front of it the
divided part consists of 'toes', five in number; the fleshy part underneath is the 'ball'; the upper part or back of
the foot is sinewy and has no particular appellation; of the toe, one portion is the 'nail' and another the joint',
and the nail is in all cases at the extremity; and toes are without exception single jointed. Men that have the
inside or sole of the foot clumsy and not arched, that is, that walk resting on the entire under-surface of their
feet, are prone to roguery. The joint common to thigh and shin is the 'knee'.

These, then, are the parts common to the male and the female sex. The relative position of the parts as to up
and down, or to front and back, or to right and left, all this as regards externals might safely be left to mere
ordinary perception. But for all that, we must treat of them for the same reason as the one previously brought
forward; that is to say, we must refer to them in order that a due and regular sequence may be observed in our
exposition, and in order that by the enumeration of these obvious facts due attention may be subsequently
given to those parts in men and other animals that are diverse in any way from one another.

In man, above all other animals, the terms 'upper' and 'lower' are used in harmony with their natural positions;
for in him, upper and lower have the same meaning as when they are applied to the universe as a whole. In
like manner the terms, 'in front', 'behind', 'right' and 'left', are used in accordance with their natural sense. But
in regard to other animals, in some cases these distinctions do not exist, and in others they do so, but in a
vague way. For instance, the head with all animals is up and above in respect to their bodies; but man alone,
as has been said, has, in maturity, this part uppermost in respect to the material universe.

15 17

HISTORY OF ANIMALS

Next after the head comes the neck, and then the chest and the back: the one in front and the other behind.
Next after these come the belly, the loins, the sexual parts, and the haunches; then the thigh and shin; and,
lastly, the feet.

The legs bend frontwards, in the direction of actual progression, and frontwards also lies that part of the foot
which is the most effective of motion, and the flexure of that part; but the heel lies at the back, and the
anklebones lie laterally, earwise. The arms are situated to right and left, and bend inwards: so that the
convexities formed by bent arms and legs are practically face to face with one another in the case of man.

As for the senses and for the organs of sensation, the eyes, the nostrils, and the tongue, all alike are situated
frontwards; the sense of hearing, and the organ of hearing, the ear, is situated sideways, on the same
horizontal plane with the eyes. The eyes in man are, in proportion to his size, nearer to one another than in
any other animal.

Of the senses man has the sense of touch more refined than any animal, and so also, but in less degree, the
sense of taste; in the development of the other senses he is surpassed by a great number of animals.

The parts, then, that are externally visible are arranged in the way above stated, and as a rule have their
special designations, and from use and wont are known familiarly to all; but this is not the case with the inner
parts. For the fact is that the inner parts of man are to a very great extent unknown, and the consequence is
that we must have recourse to an examination of the inner parts of other animals whose nature in any way
resembles that of man.

In the first place then, the brain lies in the front part of the head. And this holds alike with all animals
possessed of a brain; and all blooded animals are possessed thereof, and, by the way, molluscs as well. But,
taking size for size of animal, the largest brain, and the moistest, is that of man. Two membranes enclose it:
the stronger one near the bone of the skull; the inner one, round the brain itself, is finer. The brain in all cases
is bilateral. Behind this, right at the back, comes what is termed the 'cerebellum', differing in form from the
brain as we may both feel and see.

The back of the head is with all animals empty and hollow, whatever be its size in the different animals. For
some creatures have big heads while the face below is small in proportion, as is the case with round-faced
animals; some have little heads and long jaws, as is the case, without exception, among animals of the
mane-and-tail species.

The brain in all animals is bloodless, devoid of veins, and naturally cold to the touch; in the great majority of
animals it has a small hollow in its centre. The brain-caul around it is reticulated with veins; and this
brain-caul is that skin-like membrane which closely surrounds the brain. Above the brain is the thinnest and
weakest bone of the head, which is termed or 'sinciput'.

From the eye there go three ducts to the brain: the largest and the medium-sized to the cerebellum, the least
to the brain itself; and the least is the one situated nearest to the nostril. The two largest ones, then, run side
by side and do not meet; the medium-sized ones meet-and this is particularly visible in fishes,-for they lie
nearer than the large ones to the brain; the smallest pair are the most widely separate from one another, and
do not meet.

Inside the neck is what is termed the oesophagus (whose other name is derived oesophagus from its length
and narrowness), and the windpipe. The windpipe is situated in front of the oesophagus in all animals that

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HISTORY OF ANIMALS

have a windpipe, and all animals have one that are furnished with lungs. The windpipe is made up of gristle,
is sparingly supplied with blood, and is streaked all round with numerous minute veins; it is situated, in its
upper part, near the mouth, below the aperture formed by the nostrils into the mouth-an aperture through
which, when men, in drinking, inhale any of the liquid, this liquid finds its way out through the nostrils. In
betwixt the two openings comes the so-called epiglottis, an organ capable of being drawn over and covering
the orifice of the windpipe communicating with the mouth; the end of the tongue is attached to the epiglottis.
In the other direction the windpipe extends to the interval between the lungs, and hereupon bifurcates into
each of the two divisions of the lung; for the lung in all animals possessed of the organ has a tendency to be
double. In viviparous animals, however, the duplication is not so plainly discernible as in other species, and
the duplication is least discernible in man. And in man the organ is not split into many parts, as is the case
with some vivipara, neither is it smooth, but its surface is uneven.

In the case of the ovipara, such as birds and oviparous quadrupeds, the two parts of the organ are separated to
a distance from one another, so that the creatures appear to be furnished with a pair of lungs; and from the
windpipe, itself single, there branch off two separate parts extending to each of the two divisions of the lung.
It is attached also to the great vein and to what is designated the 'aorta'. When the windpipe is charged with
air, the air passes on to the hollow parts of the lung. These parts have divisions, composed of gristle, which
meet at an acute angle; from the divisions run passages through the entire lung, giving off smaller and smaller
ramifications. The heart also is attached to the windpipe, by connexions of fat, gristle, and sinew; and at the
point of juncture there is a hollow. When the windpipe is charged with air, the entrance of the air into the
heart, though imperceptible in some animals, is perceptible enough in the larger ones. Such are the properties
of the windpipe, and it takes in and throws out air only, and takes in nothing else either dry or liquid, or else it
causes you pain until you shall have coughed up whatever may have gone down.

The oesophagus communicates at the top with the mouth, close to the windpipe, and is attached to the
backbone and the windpipe by membranous ligaments, and at last finds its way through the midriff into the
belly. It is composed of flesh-like substance, and is elastic both lengthways and breadthways.

The stomach of man resembles that of a dog; for it is not much bigger than the bowel, but is somewhat like a
bowel of more than usual width; then comes the bowel, single, convoluted, moderately wide. The lower part
of the gut is like that of a pig; for it is broad, and the part from it to the buttocks is thick and short. The caul,
or great omentum, is attached to the middle of the stomach, and consists of a fatty membrane, as is the case
with all other animals whose stomachs are single and which have teeth in both jaws.

The mesentery is over the bowels; this also is membranous and broad, and turns to fat. It is attached to the
great vein and the aorta, and there run through it a number of veins closely packed together, extending
towards the region of the bowels, beginning above and ending below.

So much for the properties of the oesophagus, the windpipe, and the stomach.

The heart has three cavities, and is situated above the lung at the division of the windpipe, and is provided
with a fatty and thick membrane where it fastens on to the great vein and the aorta. It lies with its tapering
portion upon the aorta, and this portion is similarly situated in relation to the chest in all animals that have a
chest. In all animals alike, in those that have a chest and in those that have none, the apex of the heart points
forwards, although this fact might possibly escape notice by a change of position under dissection. The
rounded end of the heart is at the top. The apex is to a great extent fleshy and close in texture, and in the
cavities of the heart are sinews. As a rule the heart is situated in the middle of the chest in animals that have a
chest, and in man it is situated a little to the left-hand side, leaning a little way from the division of the

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HISTORY OF ANIMALS

breasts towards the left breast in the upper part of the chest.

The heart is not large, and in its general shape it is not elongated; in fact, it is somewhat round in form: only,
be it remembered, it is sharp-pointed at the bottom. It has three cavities, as has been said: the right-hand one
the largest of the three, the left-hand one the least, and the middle one intermediate in size. All these cavities,
even the two small ones, are connected by passages with the lung, and this fact is rendered quite plain in one
of the cavities. And below, at the point of attachment, in the largest cavity there is a connexion with the great
vein (near which the mesentery lies); and in the middle one there is a connexion with the aorta.

Canals lead from the heart into the lung, and branch off just as the windpipe does, running all over the lung
parallel with the passages from the windpipe. The canals from the heart are uppermost; and there is no
common passage, but the passages through their having a common wall receive the breath and pass it on to
the heart; and one of the passages conveys it to the right cavity, and the other to the left.

With regard to the great vein and the aorta we shall, by and by, treat of them together in a discussion devoted
to them and to them alone. In all animals that are furnished with a lung, and that are both internally and
externally viviparous, the lung is of all organs the most richly supplied with blood; for the lung is throughout
spongy in texture, and along by every single pore in it go branches from the great vein. Those who imagine it
to be empty are altogether mistaken; and they are led into their error by their observation of lungs removed
from animals under dissection, out of which organs the blood had all escaped immediately after death.

Of the other internal organs the heart alone contains blood. And the lung has blood not in itself but in its
veins, but the heart has blood in itself; for in each of its three cavities it has blood, but the thinnest blood is
what it has in its central cavity.

Under the lung comes the thoracic diaphragm or midriff, attached to the ribs, the hypochondria and the
backbone, with a thin membrane in the middle of it. It has veins running through it; and the diaphragm in the
case of man is thicker in proportion to the size of his frame than in other animals.

Under the diaphragm on the right-hand side lies the 'liver', and on the left-hand side the 'spleen', alike in all
animals that are provided with these organs in an ordinary and not preternatural way; for, be it observed, in
some quadrupeds these organs have been found in a transposed position. These organs are connected with the
stomach by the caul.

To outward view the spleen of man is narrow and long, resembling the self-same organ in the pig. The liver
in the great majority of animals is not provided with a 'gall-bladder'; but the latter is present in some. The
liver of a man is round-shaped, and resembles the same organ in the ox. And, by the way, the absence above
referred to of a gall-bladder is at times met with in the practice of augury. For instance, in a certain district of
the Chalcidic settlement in Euboea the sheep are devoid of gall-bladders; and in Naxos nearly all the
quadrupeds have one so large that foreigners when they offer sacrifice with such victims are bewildered with
fright, under the impression that the phenomenon is not due to natural causes, but bodes some mischief to the
individual offerers of the sacrifice.

Again, the liver is attached to the great vein, but it has no communication with the aorta; for the vein that
goes off from the great vein goes right through the liver, at a point where are the so-called 'portals' of the
liver. The spleen also is connected only with the great vein, for a vein extends to the spleen off from it.

After these organs come the 'kidneys', and these are placed close to the backbone, and resemble in character
the same organ in kine. In all animals that are provided with this organ, the right kidney is situated higher up
than the other. It has also less fatty substance than the left-hand one and is less moist. And this phenomenon
also is observable in all the other animals alike.

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HISTORY OF ANIMALS

Furthermore, passages or ducts lead into the kidneys both from the great vein and from the aorta, only not
into the cavity. For, by the way, there is a cavity in the middle of the kidney, bigger in some creatures and
less in others; but there is none in the case of the seal. This latter animal has kidneys resembling in shape the
identical organ in kine, but in its case the organs are more solid than in any other known creature. The ducts
that lead into the kidneys lose themselves in the substance of the kidneys themselves; and the proof that they
extend no farther rests on the fact that they contain no blood, nor is any clot found therein. The kidneys,
however, have, as has been said, a small cavity. From this cavity in the kidney there lead two considerable
ducts or ureters into the bladder; and others spring from the aorta, strong and continuous. And to the middle
of each of the two kidneys is attached a hollow sinewy vein, stretching right along the spine through the
narrows; by and by these veins are lost in either loin, and again become visible extending to the flank. And
these off-branchings of the veins terminate in the bladder. For the bladder lies at the extremity, and is held in
position by the ducts stretching from the kidneys, along the stalk that extends to the urethra; and pretty well
all round it is fastened by fine sinewy membranes, that resemble to some extent the thoracic diaphragm. The
bladder in man is, proportionately to his size, tolerably large.

To the stalk of the bladder the private part is attached, the external orifices coalescing; but a little lower
down, one of the openings communicates with the testicles and the other with the bladder. The penis is gristly
and sinewy in its texture. With it are connected the testicles in male animals, and the properties of these
organs we shall discuss in our general account of the said organ.

All these organs are similar in the female; for there is no difference in regard to the internal organs, except in
respect to the womb, and with reference to the appearance of this organ I must refer the reader to diagrams in
my 'Anatomy'. The womb, however, is situated over the bowel, and the bladder lies over the womb. But we
must treat by and by in our pages of the womb of all female animals viewed generally. For the wombs of all
female animals are not identical, neither do their local dispositions coincide.

These are the organs, internal and external, of man, and such is their nature and such their local disposition.

Book II

With regard to animals in general, some parts or organs are common to all, as has been said, and some are
common only to particular genera; the parts, moreover, are identical with or different from one another on the
lines already repeatedly laid down. For as a general rule all animals that are generically distinct have the
majority of their parts or organs different in form or species; and some of them they have only analogically
similar and diverse in kind or genus, while they have others that are alike in kind but specifically diverse; and
many parts or organs exist in some animals, but not in others.

For instance, viviparous quadrupeds have all a head and a neck, and all the parts or organs of the head, but
they differ each from other in the shapes of the parts. The lion has its neck composed of one single bone
instead of vertebrae; but, when dissected, the animal is found in all internal characters to resemble the dog.

The quadrupedal vivipara instead of arms have forelegs. This is true of all quadrupeds, but such of them as
have toes have, practically speaking, organs analogous to hands; at all events, they use these fore-limbs for
many purposes as hands. And they have the limbs on the left-hand side less distinct from those on the right
than man.

The fore-limbs then serve more or less the purpose of hands in quadrupeds, with the exception of the
elephant. This latter animal has its toes somewhat indistinctly defined, and its front legs are much bigger than

Book II 21

HISTORY OF ANIMALS

its hinder ones; it is five-toed, and has short ankles to its hind feet. But it has a nose such in properties and
such in size as to allow of its using the same for a hand. For it eats and drinks by lifting up its food with the
aid of this organ into its mouth, and with the same organ it lifts up articles to the driver on its back; with this
organ it can pluck up trees by the roots, and when walking through water it spouts the water up by means of
it; and this organ is capable of being crooked or coiled at the tip, but not of flexing like a joint, for it is
composed of gristle.

Of all animals man alone can learn to make equal use of both hands.

All animals have a part analogous to the chest in man, but not similar to his; for the chest in man is broad, but
that of all other animals is narrow. Moreover, no other animal but man has breasts in front; the elephant,
certainly, has two breasts, not however in the chest, but near it.

Moreover, also, animals have the flexions of their fore and hind limbs in directions opposite to one another,
and in directions the reverse of those observed in the arms and legs of man; with the exception of the
elephant. In other words, with the viviparous quadrupeds the front legs bend forwards and the hind ones
backwards, and the concavities of the two pairs of limbs thus face one another.

The elephant does not sleep standing, as some were wont to assert, but it bends its legs and settles down; only
that in consequence of its weight it cannot bend its leg on both sides simultaneously, but falls into a
recumbent position on one side or the other, and in this position it goes to sleep. And it bends its hind legs
just as a man bends his legs.

In the case of the ovipara, as the crocodile and the lizard and the like, both pairs of legs, fore and hind, bend
forwards, with a slight swerve on one side. The flexion is similar in the case of the multipeds; only that the
legs in between the extreme ends always move in a manner intermediate between that of those in front and
those behind, and accordingly bend sideways rather than backwards or forwards. But man bends his arms and
his legs towards the same point, and therefore in opposite ways: that is to say, he bends his arms backwards,
with just a slight inclination inwards, and his legs frontwards. No animal bends both its fore-limbs and
hind-limbs backwards; but in the case of all animals the flexion of the shoulders is in the opposite direction
to that of the elbows or the joints of the forelegs, and the flexure in the hips to that of the knees of the
hind-legs: so that since man differs from other animals in flexion, those animals that possess such parts as
these move them contrariwise to man.

Birds have the flexions of their limbs like those of the quadrupeds; for, although bipeds, they bend their legs
backwards, and instead of arms or front legs have wings which bend frontwards.

The seal is a kind of imperfect or crippled quadruped; for just behind the shoulder-blade its front feet are
placed, resembling hands, like the front paws of the bear; for they are furnished with five toes, and each of
the toes has three flexions and a nail of inconsiderable size. The hind feet are also furnished with five toes; in
their flexions and nails they resemble the front feet, and in shape they resemble a fish's tail.

The movements of animals, quadruped and multiped, are crosswise, or in diagonals, and their equilibrium in
standing posture is maintained crosswise; and it is always the limb on the right-hand side that is the first to
move. The lion, however, and the two species of camels, both the Bactrian and the Arabian, progress by an
amble; and the action so called is when the animal never overpasses the right with the left, but always follows
close upon it.

Whatever parts men have in front, these parts quadrupeds have below, in or on the belly; and whatever parts
men have behind, these parts quadrupeds have above on their backs. Most quadrupeds have a tail; for even
the seal has a tiny one resembling that of the stag. Regarding the tails of the pithecoids we must give their

Book II 22

HISTORY OF ANIMALS

distinctive properties by and by animal

All viviparous quadrupeds are hair-coated, whereas man has only a few short hairs excepting on the head,
but, so far as the head is concerned, he is hairier than any other animal. Further, of hair-coated animals, the
back is hairier than the belly, which latter is either comparatively void of hair or smooth and void of hair
altogether. With man the reverse is the case.

Man also has upper and lower eyelashes, and hair under the armpits and on the pubes. No other animal has
hair in either of these localities, or has an under eyelash; though in the case of some animals a few straggling
hairs grow under the eyelid.

Of hair-coated quadrupeds some are hairy all over the body, as the pig, the bear, and the dog; others are
especially hairy on the neck and all round about it, as is the case with animals that have a shaggy mane, such
as the lion; others again are especially hairy on the upper surface of the neck from the head as far as the
withers, namely, such as have a crested mane, as in the case with the horse, the mule, and, among the
undomesticated horned animals, the bison.

The so-called hippelaphus also has a mane on its withers, and the animal called pardion, in either case a thin
mane extending from the head to the withers; the hippelaphus has, exceptionally, a beard by the larynx. Both
these animals have horns and are cloven-footed; the female, however, of the hippelaphus has no horns. This
latter animal resembles the stag in size; it is found in the territory of the Arachotae, where the wild cattle also
are found. Wild cattle differ from their domesticated congeners just as the wild boar differs from the
domesticated one. That is to say they are black, strong looking, with a hook-nosed muzzle, and with horns
lying more over the back. The horns of the hippelaphus resemble those of the gazelle.

The elephant, by the way, is the least hairy of all quadrupeds. With animals, as a general rule, the tail
corresponds with the body as regards thickness or thinness of hair-coating; that is, with animals that have
long tails, for some creatures have tails of altogether insignificant size.

Camels have an exceptional organ wherein they differ from all other animals, and that is the so-called 'hump'
on their back. The Bactrian camel differs from the Arabian; for the former has two humps and the latter only
one, though it has, by the way, a kind of a hump below like the one above, on which, when it kneels, the
weight of the whole body rests. The camel has four teats like the cow, a tail like that of an ass, and the privy
parts of the male are directed backwards. It has one knee in each leg, and the flexures of the limb are not
manifold, as some say, although they appear to be so from the constricted shape of the region of the belly. It
has a huckle-bone like that of kine, but meagre and small in proportion to its bulk. It is cloven-footed, and
has not got teeth in both jaws; and it is cloven footed in the following way: at the back there is a slight cleft
extending as far up as the second joint of the toes; and in front there are small hooves on the tip of the first
joint of the toes; and a sort of web passes across the cleft, as in geese. The foot is fleshy underneath, like that
of the bear; so that, when the animal goes to war, they protect its feet, when they get sore, with sandals.

The legs of all quadrupeds are bony, sinewy, and fleshless; and in point of fact such is the case with all
animals that are furnished with feet, with the exception of man. They are also unfurnished with buttocks; and
this last point is plain in an especial degree in birds. It is the reverse with man; for there is scarcely any part
of the body in which man is so fleshy as in the buttock, the thigh, and the calf; for the part of the leg called
gastroenemia or is fleshy.

Of blooded and viviparous quadrupeds some have the foot cloven into many parts, as is the case with the
hands and feet of man (for some animals, by the way, are many-toed, as the lion, the dog, and the pard);
others have feet cloven in twain, and instead of nails have hooves, as the sheep, the goat, the deer, and the
hippopotamus; others are uncloven of foot, such for instance as the solid-hooved animals, the horse and the

Book II 23

HISTORY OF ANIMALS

mule. Swine are either cloven-footed or uncloven-footed; for there are in Illyria and in Paeonia and
elsewhere solid-hooved swine. The cloven-footed animals have two clefts behind; in the solid-hooved this
part is continuous and undivided.

Furthermore, of animals some are horned, and some are not so. The great majority of the horned animals are
cloven-footed, as the ox, the stag, the goat; and a solid-hooved animal with a pair of horns has never yet
been met with. But a few animals are known to be singled-horned and single-hooved, as the Indian ass; and
one, to wit the oryx, is single horned and cloven-hooved.

Of all solid-hooved animals the Indian ass alone has an astragalus or huckle-bone; for the pig, as was said
above, is either solid-hooved or cloven-footed, and consequently has no well-formed huckle-bone. Of the
cloven footed many are provided with a huckle-bone. Of the many-fingered or many-toed, no single one has
been observed to have a huckle-bone, none of the others any more than man. The lynx, however, has
something like a hemiastragal, and the lion something resembling the sculptor's 'labyrinth'. All the animals
that have a huckle-bone have it in the hinder legs. They have also the bone placed straight up in the joint; the
upper part, outside; the lower part, inside; the sides called Coa turned towards one another, the sides called
Chia outside, and the keraiae or 'horns' on the top. This, then, is the position of the hucklebone in the case of
all animals provided with the part.

Some animals are, at one and the same time, furnished with a mane and furnished also with a pair of horns
bent in towards one another, as is the bison (or aurochs), which is found in Paeonia and Maedica. But all
animals that are horned are quadrupedal, except in cases where a creature is said metaphorically, or by a
figure of speech, to have horns; just as the Egyptians describe the serpents found in the neighbourhood of
Thebes, while in point of fact the creatures have merely protuberances on the head sufficiently large to
suggest such an epithet.

Of horned animals the deer alone has a horn, or antler, hard and solid throughout. The horns of other animals
are hollow for a certain distance, and solid towards the extremity. The hollow part is derived from the skin,
but the core round which this is wrapped-the hard part-is derived from the bones; as is the case with the
horns of oxen. The deer is the only animal that sheds its horns, and it does so annually, after reaching the age
of two years, and again renews them. All other animals retain their horns permanently, unless the horns be
damaged by accident.

Again, with regard to the breasts and the generative organs, animals differ widely from one another and from
man. For instance, the breasts of some animals are situated in front, either in the chest or near to it, and there
are in such cases two breasts and two teats, as is the case with man and the elephant, as previously stated.