Various Works

by Aristotle

  of desire is the pleasant. The part, however, by which food produces

  the sensation is not precisely alike in all of them, but while in some

  it is free from attachments, in others, where it is not required for

  vocal pur, poses, it is adherent. In some again it is hard, in

  others soft or flesh-like. Thus even the Crustacea, the Carabi for

  instance and the like, and the Cephalopods, such as the Sepias and the

  Poulps, have some such part inside the mouth. As for the Insects, some

  of them have the part which serves as tongue inside the mouth, as is

  the case with ants, and as is also the case with many Testacea,

  while in others it is placed externally. In this latter case it

  resembles a sting, and is hollow and spongy, so as to serve at one and

  the same time for the tasting and for the sucking up of nutriment.

  This is plainly to be seen in flies and bees and all such animals, and

  likewise in some of the Testacea. In the Purpurae, for instance, so

  strong is this part that it enables them to bore holes through the

  hard covering of shell-fish, of the spiral snails, for example, that

  are used as bait to catch them. So also the gad-flies and cattle-flies

  can pierce through the skin of man, and some of them even through

  the skins of other animals. Such, then, in these animals is the nature

  of the tongue, which is thus as it were the counterpart of the

  elephant's nostril. For as in the elephant the nostril is used as a

  weapon, so in these animals the tongue serves as a sting.

  In all other animals the tongue agrees with description already

  given.

  Book III

  1

  WE have next to consider the teeth, and with these the mouth, that

  is the cavity which they enclose and form. The teeth have one

  invariable office, namely the reduction of food; but besides this

  general function they have other special ones, and these differ in

  different groups. Thus in some animals the teeth serve as weapons; but

  this with a distinction. For there are offensive weapons and there are

  defensive weapons; and while in some animals, as the wild Carnivora,

  the teeth answer both purposes, in many others, both wild and

  domesticated, they serve only for defence. In man the teeth are

  admirably constructed for their general office, the front ones being

  sharp, so as to cut the food into bits, and the hinder ones broad

  and flat, so as to grind it to a pulp; while between these and

  separating them are the dog-teeth, which, in accordance with the

  rule that the mean partakes of both extremes, share in the

  characters of those on either side, being broad in one part but

  sharp in another. Similar distinctions of shape are presented by the

  teeth of other animals, with the exception of those whose teeth are

  one and all of the sharp kind. In man, however, the number and the

  character even of these sharp teeth have been mainly determined by the

  requirements of speech. For the front teeth of man contribute in

  many ways to the formation of letter-sounds.

  In some animals, however, the teeth, as already said, serve merely

  for the reduction of food. When, besides this, they serve as offensive

  and defensive weapons, they may either be formed into tusks, as for

  instance is the case in swine, or may be sharp-pointed and interlock

  with those of the opposite jaw, in which case the animal is said to be

  saw-toothed. The explanation of this latter arrangement is as follows.

  The strength of such an animal is in its teeth, and these depend for

  their efficiency on their sharpness. In order, then, to prevent

  their getting blunted by mutual friction, such of them as serve for

  weapons fit into each other's interspaces, and are so kept in proper

  condition. No animal that has sharp interfitting teeth is at the

  same time furnished with tusks. For nature never makes anything

  superfluous or in vain. She gives, therefore, tusks to such animals as

  strike in fighting, and serrated teeth to such as bite. Sows, for

  instance, have no tusks, and accordingly sows bite instead of

  striking.

  A general principle must here be noted, which will be found

  applicable not only in this instance but in many others that will

  occur later on. Nature allots each weapon, offensive and defensive

  alike, to those animals alone that can use it; or, if not to them

  alone, to them in a more marked degree; and she allots it in its

  most perfect state to those that can use it best; and this whether

  it be a sting, or a spur, or horns, or tusks, or what it may of a like

  kind.

  Thus as males are stronger and more choleric than females, it is

  in males that such parts as those just mentioned are found, either

  exclusively, as in some species, or more fully developed, as in

  others. For though females are of course provided with such parts as

  are no less necessary to them than to males, the parts, for

  instance, which subserve nutrition, they have even these in an

  inferior degree, and the parts which answer no such necessary

  purpose they do not possess at all. This explains why stags have

  horns, while does have none; why the horns of cows are different

  from those of bulls, and, similarly, the horns of ewes from those of

  rams. It explains also why the females are often without spurs in

  species where the males are provided with them, and accounts for

  similar facts relating to all other such parts.

  All fishes have teeth of the serrated form, with the single

  exception of the fish known as the Scarus. In many of them there are

  teeth even on the tongue and on the roof of the mouth. The reason

  for this is that, living as they do in the water, they cannot but

  allow this fluid to pass into the mouth with the food. The fluid

  thus admitted they must necessarily discharge again without delay. For

  were they not to do so, but to retain it for a time while

  triturating the food, the water would run into their digestive

  cavities. Their teeth therefore are all sharp, being adapted only

  for cutting, and are numerous and set in many parts, that their

  abundance may serve in lieu of any grinding faculty, to mince the food

  into small bits. They are also curved, because these are almost the

  only weapons which fishes possess.

  In all these offices of the teeth the mouth also takes its part; but

  besides these functions it is subservient to respiration, in all

  such animals as breathe and are cooled by external agency. For nature,

  as already said, uses the parts which are common to all animals for

  many special purposes, and this of her own accord. Thus the mouth

  has one universal function in all animals alike, namely its alimentary

  office; but in some, besides this, the special duty of serving as a

  weapon is attached to it; in others that of ministering to speech; and

  again in many, though not in all, the office of respiration. All these

  functions are thrown by nature upon one single organ, the construction

  of which she varies so as to suit the variations of office.

  Therefore it is that in some animals the mouth is contracted, while in

  othe
rs it is of wide dimensions. The contracted form belongs to such

  animals as use the mouth merely for nutritive, respiratory, and

  vocal purposes; whereas in such as use it as a means of defence it has

  a wide gape. This is its invariable form in such animals as are

  saw-toothed. For seeing that their mode of warfare consists in biting,

  it is advantageous to them that their mouth shall have a wide opening;

  for the wider it opens, the greater will be the extent of the bite,

  and the more numerous will be the teeth called into play.

  What has just been said applies to fishes as well as to other

  animals; and thus in such of them as are carnivorous, and made for

  biting, the mouth has a wide gape; whereas in the rest it is small,

  being placed at the extremity of a tapering snout. For this form is

  suited for their purposes, while the other would be useless.

  In birds the mouth consists of what is called the beak, which in

  them is a substitute for lips and teeth. This beak presents variations

  in harmony with the functions and protective purposes which it serves.

  Thus in those birds that are called Crooked-clawed it is invariably

  hooked, inasmuch as these birds are carnivorous, and eat no kind of

  vegetable food whatsoever. For this form renders it serviceable to

  them in obtaining the mastery over their prey, and is better suited

  for deeds of violence than any other. Moreover, as their weapons of

  offence consist of this beak and of their claws, these latter also are

  more crooked in them than in the generality of birds. Similarly in

  each other kind of bird the beak is suited to the mode of life.

  Thus, in woodpeckers it is hard and strong, as also in crows and birds

  of crowlike habit, while in the smaller birds it is delicate, so as to

  be of use in collecting seeds and picking up minute animals. In such

  birds, again, as eat herbage, and such as live about marshes-those,

  for example, that swim and have webbed feet-the bill is broad, or

  adapted in some other way to the mode of life. For a broad bill

  enables a bird to dig into the ground with ease, just as, among

  quadrupeds, does the broad snout of the pig, an animal which, like the

  birds in question, lives on roots. Moreover, in these root-eating

  birds and in some others of like habits of life, the tips of the

  bill end in hard points, which gives them additional facility in

  dealing with herbaceous food.

  The several parts which are set on the head have now, pretty

  nearly all, been considered. In man, however, the part which lies

  between the head and the neck is called the face, this name,

  (prosopon) being, it would seem, derived from the function of the

  part. For as man is the only animal that stands erect, he is also

  the only one that looks directly in front (proso) and the only one

  whose voice is emitted in that direction.

  2

  We have now to treat of horns; for these also, when present, are

  appendages of the head. They exist in none but viviparous animals;

  though in some ovipara certain parts are metaphorically spoken of as

  horns, in virtue of a certain resemblance. To none of such parts,

  however, does the proper office of a horn belong; for they are never

  used, as are the horns of vivipara, for purposes which require

  strength, whether it be in self-protection or in offensive strife.

  So also no polydactylous animal is furnished with horns. For horns are

  defensive weapons, and these polydactylous animals possess other means

  of security. For to some of them nature has given claws, to others

  teeth suited for combat, and to the rest some other adequate defensive

  appliance. There are horns, however, in most of the cloven-hoofed

  animals, and in some of those that have a solid hoof, serving them

  as an offensive weapon, and in some cases also as a defensive one.

  There are horns also in all animals that have not been provided by

  nature with some other means of security; such means, for instance, as

  speed, which has been given to horses; or great size, as in camels;

  for excessive bulk, such as has been given to these animals, and in

  a still greater measure to elephants, is sufficient in itself to

  protect an animal from being destroyed by others. Other animals

  again are protected by the possession of tusks; and among these are

  the swine, though they have a cloven hoof.

  All animals again, whose horns are but useless appendages, have been

  provided by nature with some additional means of security. Thus deer

  are endowed with speed; for the large size and great branching of

  their horns makes these a source of detriment rather than of profit to

  their possessors. Similarly endowed are the Bubalus and gazelle; for

  though these animals will stand up against some enemies and defend

  themselves with their horns, yet they run away from such as are fierce

  and pugnacious. The Bonasus again, whoe horns curve inwards towards

  each other, is provided with a means of protection in the discharge of

  its excrement; and of this it avails itself when frightened. There are

  some other animals besides the Bonasus that have a similar mode of

  defence. In no case, however, does nature ever give more than one

  adequate means of protection to one and the same animal.

  Most of the animals that have horns are cloven-hoofed; but the

  Indian ass, as they call it, is also reported to be horned, though its

  hoof is solid.

  Again as the body, so far as regards its organs of motion,

  consists of two distinct parts, the right and the left, so also and

  for like reasons the horns of animals are, in the great majority of

  cases, two in number. Still there are some that have but a single

  horn; the Oryx, for instance, and the so-called Indian ass; in the

  former of which the hoof is cloven, while in the latter it is solid.

  In such animals the horn is set in the centre of the head; for as

  the middle belongs equally to both extremes, this arrangement is the

  one that comes nearest to each side having its own horn.

  Again, it would appear consistent with reason that the single horn

  should go with the solid rather than with the cloven hoof. For hoof,

  whether solid or cloven, is of the same nature as horn; so that the

  two naturally undergo division simultaneously and in the same animals.

  Again, since the division of the cloven hoof depends on deficiency

  of material, it is but rationally consistent, that nature, when she

  gave an animal an excess of material for the hoofs, which thus

  became solid, should have taken away something from the upper parts

  and so made the animal to have but one horn. Rightly too did she act

  when she chose the head whereon to set the horns; and AEsop's Momus is

  beside the mark, when he finds fault with the bull for not having

  its horns upon its shoulders. For from this position, says he, they

  would have delivered their blow with the greatest force, whereas on

  the head they occupy the weakest part of the whole body. Momus was but

  dull-sighted in making this hostile criticism. For had the horns

  been set on the shoulders, or had they been set on any other part than

/>   they are, the encumbrance of their weight would have been increased,

  not only without any compensating gain whatso::ver, but with the

  disadvantage of impeding many bodily operations. For the point

  whence the blows could be delivered with the greatest force was not

  the only matter to be considered, but the point also whence they could

  be delivered with the widest range. But as the bull has no hands and

  cannot possibly have its horns on its feet or on its knees, where they

  would prevent flexion, there remains no other site for them but the

  head; and this therefore they necessarily occupy. In this position,

  moreover, they are much less in the way of the movements of the body

  than they would be elsewhere.

  Deer are the only animals in which the horns are solid throughout,

  and are also the only animals that cast them. This casting is not

  simply advantageous to the deer from the increased lightness which

  it produces, but, seeing how heavy the horns are, is a matter of

  actual necessity.

  In all other animals the horns are hollow for a certain distance,

  and the end alone is solid, this being the part of use in a blow. At

  the same time, to prevent even the hollow part from being weak, the

  horn, though it grows out of the skin, has a solid piece from the

  bones fitted into its cavity. For this arrangement is not only that

  which makes the horns of the greatest service in fighting, but that

  which causes them to be as little of an impediment as possible in

  the other actions of life.

  Such then are the reasons for which horns exist; and such the

  reasons why they are present in some animals, absent from others.

  Let us now consider the character of the material nature whose

  necessary results have been made available by rational nature for a

  final cause.

  In the first place, then, the larger the bulk of animals, the

  greater is the proportion of corporeal and earthy matter which they

  contain. Thus no very small animal is known to have horns, the

  smallest horned animal that we are acquainted with being the