by Aristotle
heart. But the head has also been chosen by nature as the part in
which to set some of the senses; because its blood is mixed in such
suitable proportions as to ensure their tranquillity and precision,
while at the same time it can supply the brain with such warmth as
it requires. There is yet a third constituent superadded to the
head, namely the part which ministers to the ingestion of food. This
has been placed here by nature, because such a situation accords
best with the general configuration of the body. For the stomach could
not possibly be placed above the heart, seeing that this is the
sovereign organ; and if placed below, as in fact it is, then the mouth
could not possibly be placed there also. For this would have
necessitated a great increase in the length of the body; and the
stomach, moreover, would have been removed too far from the source
of motion and of concoction.
The head, then, exists for the sake of these three parts; while
the neck, again, exists for the sake of the windpipe. For it acts as a
defence to this and to the oesophagus, encircling them and keeping
them from injury. In all other animals this neck is flexible and
contains several vertebrae; but in wolves and lions it contains only a
single bone. For the object of nature was to give these animals an
organ which should be serviceable in the way of strength, rather
than one that should be useful for any of the other purposes to
which necks are subservient.
Continuous with the head and neck is the trunk with the anterior
limbs. In man the forelegs and forefeet are replaced by arms and by
what we call hands. For of all animals man alone stands erect, in
accordance with his godlike nature and essence. For it is the function
of the god-like to think and to be wise; and no easy task were this
under the burden of a heavy body, pressing down from above and
obstructing by its weight the motions of the intellect and of the
general sense. When, moreover, the weight and corporeal substance
become excessive, the body must of necessity incline towards the
ground. In such cases therefore nature, in order to give support to
the body, has replaced the arms and hands by forefeet, and has thus
converted the animal into a quadruped. For, as every animal that walks
must of necessity have the two hinder feet, such an animal becomes a
quadruped, its body inclining downwards in front from the weight which
its soul cannot sustain. For all animals, man alone excepted, are
dwarf-like in form. For the dwarf-like is that in which the upper part
is large, while that which bears the weight and is used in progression
is small. This upper part is what we call the trunk, which reaches
from the mouth to the vent. In man it is duly proportionate to the
part below, and diminishes much in its comparative size as the man
attains to full growth. But in his infancy the contrary obtains, and
the upper parts are large, while the lower part is small; so that
the infant can only crawl, and is unable to walk; nay, at first cannot
even crawl, but remains without motion. For all children are dwarfs in
shape, but cease to be so as they become men, from the growth of their
lower part; whereas in quadrupeds the reverse occurs, their lower
parts being largest in youth, and advance of years bringing
increased growth above, that is in the trunk, which extends from the
rump to the head. Thus it is that colts are scarcely, if at all, below
full-grown horses in height; and that while still young they can touch
their heads with the hind legs, though this is no longer possible when
they are older. Such, then, is the form of animals that have either
a solid or a cloven hoof. But such as are polydactylous and without
horns, though they too are of dwarf-like shape, are so in a less
degree; and therefore the greater growth of the lower parts as
compared with the upper is also small, being proportionate to this
smaller deficiency.
Dwarf-like again is the race of birds and fishes; and so in fact, as
already has been said, is every animal that has blood. This is the
reason why no other animal is so intelligent as man. For even among
men themselves if we compare children with adults, or such adults as
are of dwarf-like shape with such as are not, we find that, whatever
other superiority the former may possess, they are at any rate
deficient as compared with the latter in intelligence. The
explanation, as already stated, is that their psychical principle is
corporeal, and much impeded in its motions. Let now a further decrease
occur in the elevating heat, and a further increase in the earthy
matter, and the animals become smaller in bulk, and their feet more
numerous, until at a later stage they become apodous, and extended
full length on the ground. Then, by further small successions of
change, they come to have their principal organ below; and at last
their cephalic part becomes motionless and destitute of sensation.
Thus the animal becomes a plant, that has its upper parts downwards
and its lower parts above. For in plants the roots are the equivalents
of mouth and head, while the seed has an opposite significance, for it
is produced above it the extremities of the twigs.
The reasons have now been stated why some animals have many feet,
some only two, and others none; why, also, some living things are
plants and others animals; and, lastly, why man alone of all animals
stands erect. Standing thus erect, man has no need of legs in front,
and in their stead has been endowed by nature with arms and hands. Now
it is the opinion of Anaxagoras that the possession of these hands
is the cause of man being of all animals the most intelligent. But
it is more rational to suppose that his endowment with hands is the
consequence rather than the cause of his superior intelligence. For
the hands are instruments or organs, and the invariable plan of nature
in distributing the organs is to give each to such animal as can
make use of it; nature acting in this matter as any prudent man
would do. For it is a better plan to take a person who is already a
flute-player and give him a flute, than to take one who possesses a
flute and teach him the art of flute-playing. For nature adds that
which is less to that which is greater and more important, and not
that which is more valuable and greater to that which is less.
Seeing then that such is the better course, and seeing also that of
what is possible nature invariably brings about the best, we must
conclude that man does not owe his superior intelligence to his hands,
but his hands to his superior intelligence. For the most intelligent
of animals is the one who would put the most organs to use; and the
hand is not to be looked on as one organ but as many; for it is, as it
were, an instrument for further instruments. This instrument,
therefore,-the hand-of all instruments the most variously serviceable,
has been given by nature to man, the animal of all animals the most
capable of acquiring the most varied handic
rafts.
Much in error, then, are they who say that the construction of man
is not only faulty, but inferior to that of all other animals;
seeing that he is, as they point out, bare-footed, naked, and
without weapon of which to avail himself. For other animals have
each but one mode of defence, and this they can never change; so
that they must perform all the offices of life and even, so to
speak, sleep with sandals on, never laying aside whatever serves as
a protection to their bodies, nor changing such single weapon as
they may chance to possess. But to man numerous modes of defence are
open, and these, moreover, he may change at will; as also he may adopt
such weapon as he pleases, and at such times as suit him. For the hand
is talon, hoof, and horn, at will. So too it is spear, and sword,
and whatsoever other weapon or instrument you please; for all these
can it be from its power of grasping and holding them all. In
harmony with this varied office is the form which nature has contrived
for it. For it is split into several divisions, and these are
capable of divergence. Such capacity of divergence does not prevent
their again converging so as to form a single compact body, whereas
had the hand been an undivided mass, divergence would have been
impossible. The divisions also may be used singly or two together
and in various combinations. The joints, moreover, of the fingers
are well constructed for prehension and for pressure. One of these
also, and this not long like the rest but short and thick, is placed
laterally. For were it not so placed all prehension would be as
impossible, as were there no hand at all. For the pressure of this
digit is applied from below upwards, while the rest act from above
downwards; an arrangement which is essential, if the grasp is to be
firm and hold like a tight clamp. As for the shortness of this
digit, the object is to increase its strength, so that it may be able,
though but one, to counterbalance its more numerous opponents.
Moreover, were it long it would be of no use. This is the
explanation of its being sometimes called the great digit, in spite of
its small size; for without it all the rest would be practically
useless. The finger which stands at the other end of the row is small,
while the central one of all is long, like a centre oar in a ship.
This is rightly so; for it is mainly by the central part of the
encircling grasp that a tool must be held when put to use.
No less skilfully contrived are the nails. For, while in man these
serve simply as coverings to protect the tips of the fingers, in other
animals they are also used for active purposes; and their form in each
case is suited to their office.
The arms in man and the fore limbs in quadrupeds bend in contrary
directions, this difference having reference to the ingestion of
food and to the other offices which belong to these parts. For
quadrupeds must of necessity bend their anterior limbs inwards that
they may serve in locomotion, for they use them as feet. Not but
what even among quadrupeds there is at any rate a tendency for such as
are polydactylous to use their forefeet not only for locomotion but as
hands. And they are in fact so used, as any one may see. For these
animals seize hold of objects, and also repel assailants with their
anterior limbs; whereas quadrupeds with solid hoofs use their hind
legs for this latter purpose. For their fore limbs are not analogous
to the arms and hands of man.
It is this hand-like office of the anterior limbs which explains why
in some of the polydactylous quadrupeds, such as wolves, lions,
dogs, and leopards, there are actually five digits on each forefoot,
though there are only four on each hind one. For the fifth digit of
the foot corresponds to the fifth digit of the hand, and like it is
called the big one. It is true that in the smaller polydactylous
quadrupeds the hind feet also have each five toes. But this is because
these animals are creepers; and the increased number of nails serves
to give them a tighter grip, and so enables them to creep up steep
places with greater facility, or even to run head downwards.
In man between the arms, and in other animals between the
forelegs, lies what is called the breast. This in man is broad, as one
might expect; for as the arms are set laterally on the body, they
offer no impediment to such expansion in this part. But in
quadrupeds the breast is narrow, owing to the legs having to be
extended in a forward direction in progression and locomotion.
Owing to this narrowness the mammae of quadrupeds are never placed
on the breast. But in the human body there is ample space in this
part; moreover, the heart and neighbouring organs require
protection, and for these reasons this part is fleshy and the mammae
are placed upon it separately, side by side, being themselves of a
fleshy substance in the male and therefore of use in the way just
stated; while in the female, nature, in accordance with what we say is
her frequent practice, makes them minister to an additional
function, employing them as a store-place of nutriment for the
offspring. The human mammae are two in number, in accordance with
the division of the body into two halves, a right and a left. They are
somewhat firmer than they would otherwise be, because the ribs in this
region are joined together; while they form two separate masses,
because their presence is in no wise burdensome. In other animals than
man, it is impossible for the mammae to be placed on the breast
between the forelegs, for they would interfere with locomotion; they
are therefore disposed of otherwise, and in a variety of ways. Thus in
such animals as produce but few at a birth, whether horned
quadrupeds or those with solid hoofs, the mammae are placed in the
region of the thighs, and are two in number, while in such as
produce litters, or such as are polydactylous, the dugs are either
numerous and placed laterally on the belly, as in swine and dogs, or
are only two in number, being set, however, in the centre of the
abdomen, as is the case in the lion. The explanation of this latter
condition is not that the lion produces few at a birth, for
sometimes it has more than two cubs at a time, but is to be found in
the fact that this animal has no plentiful supply of milk. For,
being a flesheater, it gets food at but rare intervals, and such
nourishment as it obtains is all expended on the growth of its body.
In the elephant also there are but two mammae, which are placed
under the axillae of the fore limbs. The mammae are not more than two,
because this animal has only a single young one at a birth; and they
are not placed in the region of the thighs, because they never
occupy that position in any polydactylous animal such as this. Lastly,
they are placed above, close to the axillae, because this is the
position of the foremost dugs in all animals whose dugs are
numerous, and the dugs so placed give the most milk. Evidence of
this i
s furnished by the sow. For she always presents these foremost
dugs to the first-born of her litter. A single young one is of
course a first-born, and so such animals as only produce a single
young one must have these anterior dugs to present to it; that is they
must have the dugs which are under the axillae. This, then, is the
reason why the elephant has but two mammae, and why they are so
placed. But, in such animals as have litters of young, the dugs are
disposed about the belly; the reason being that more dugs are required
by those that will have more young to nourish. Now it is impossible
that these dugs should be set transversely in rows of more than two,
one, that is, for each side of the body, the right and the left;
they must therefore be placed lengthways, and the only place where
there is sufficient length for this is the region between the front
and hind legs. As to the animals that are not polydactylous but
produce few at a birth, or have horns, their dugs are placed in the
region of the thighs. The horse, the ass, the camel are examples;
all of which bear but a single young one at a time, and of which the
two former have solid hoofs, while in the last the hoof is cloven.
As still further examples may be mentioned the deer, the ox, the goat,
and all other similar animals.
The explanation is that in these animals growth takes place in an
upward direction; so that there must be an abundant collection of
residual matter and of blood in the lower region, that is to say in
the neighbourhood of the orifices for efflux, and here therefore
nature has placed the mammae. For the place in which the nutriment
is set in motion must also be the place whence nutriment can be
derived by them. In man there are mammae in the male as well as in the
female; but some of the males of other animals are without them. Such,
for instance, is the case with horses, some stallions being
destitute of these parts, while others that resemble their dams have
them. Thus much then concerning the mammae.
Next after the breast comes the region of the belly, which is left
unenclosed by the ribs for a reason which has already been given;