by Aristotle
In crocodiles the immobility of the lower jaw also contributes in some measure to stunt the development of the tongue. For the crocodile’s tongue is adherent to the lower jaw. For its upper and lower jaws are, as it were, inverted, it being the upper jaw which in other animals is the immovable one. The tongue, however, of this animal is not attached to the upper jaw, because that would interfere with the [30] ingestion of food, but adheres to the lower jaw, because this is, as it were, the upper one which has changed its place. Moreover, it is the crocodile’s lot, though a land animal, to live the life of a fish, and this again necessarily involves an indistinct formation of the part in question.
[35] The roof of the mouth resembles flesh, even in many of the fishes; and in some of the river species, as for instance in the fishes known as Cyprini, is so very [661a1] flesh-like and soft as to be taken by careless observers for a tongue. The tongue of fishes, however, though it exists as a separate part, is never formed with such distinctness as this, as has been already explained. Again, the gustatory sensibility [5] is not diffused equally over the whole surface of the tongue-like organ, but is placed chiefly in the tip; and for this reason it is the tip which is the only part of the tongue separated in fishes from the rest of the mouth. As all animals are sensible to the pleasure derivable from food, they all feel a desire for it. For the object of desire is the pleasant. The part, however, by which food produces the sensation is not alike in [10] all of them, but while in some it is free from attachments, in others, where it is not required for vocal purposes, it is adherent. In some again it is hard, in others soft or flesh-like. Thus even the Crustacea, the crayfish for instance and the like, and the [15] Cephalopods, such as the cuttlefish and the octopus, 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 [20] 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 purple murex, 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 [25] 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 defence, so in these animals the tongue serves as a sting.
[30] In all other animals the tongue agrees with the description already given.
BOOK III
1 · We have next to consider the teeth, and with these the mouth which they [661b1] 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 [5] 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 molars broad and flat, so as to grind it to a pulp; while between these and separating them are the canines which, in accordance [10] 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 [15] 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. For the strength of such an animal is in its [20] 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. No animal that has saw-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 [25] such as bite. Sows, for instance, have no tusks, and accordingly sows bite.
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 [30] not to them alone, to them in a more marked degree; and she allots it in its most perfect state to those than 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 necessary to them, the parts, for instance, which subserve [35] 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 [662a1] 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, [5] and accounts for similar facts relating to all other such parts.
All fishes have teeth of the saw-toothed 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 [10] admitted they must necessarily discharge again without delay. For they cannot spend time grinding their food, since 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 [15] they 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 [20] 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. [25] Therefore it is that in some animals the mouth is contracted, while in others 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 [30] opens, the greater will be the extent of the bite, and the more numerous will be the teeth
called into play.
Biting and carnivorous fish have a mouth of that sort, whereas in the rest it is 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 [662b1] 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. For this form renders it serviceable to them in obtaining the mastery over their prey, and is better suited for deeds of violence than [5] 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 crow-like habit, while in the smaller birds it is delicate, so as to be of use in collecting seeds and [10] 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. [15] 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 being, it would seem, derived from the function of the [20] part. For as man is the only animal that stands erect, he is also the only one that looks directly in front; and the only one whose voice is emitted in that direction.10
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 [25] resemblance. To none of such parts, however, does the proper office of a horn belong; for the vivipara have their horns for the sake of defence and attack, but this is not the case with any of the other creatures said to have horns; for they do not use their horns in defence or for mastery, which are tasks requiring strength. So also no [30] 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 [663a1] offensive weapon. Horns also serve for defence 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, [5] 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 [10] 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 antelope 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 bison again, whose horns curve inwards towards each other, is provided with a means of protection in the discharge of its excrement; and of this it [15] avails itself when frightened. There are some other animals 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 [20] distinct parts, the right and the left, so also and for the same 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 [25] 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 [30] 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.
[35] Rightly too did she act when she chose the head whereon to set the horns; and Æsop’s Momus is beside the mark, when he finds fault with the bull for not having [663b1] 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 [5] criticism. For had the horns been set on any other part than they are, the encumbrance of their weight would have been increased, not only without any compensating gain whatsoever, but with the disadvantage of impeding many bodily operations—and similarly if they had been set on the shoulders. 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 [10] 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 for the advantage of the deer from the increased lightness which it produces, but, seeing how heavy the horns are, it is also a matter of necessity.
[15] 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 which grows out of the skin from being weak, the solid part fitted into it comes up from the bones. 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 [20] 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 employed by rational nature for a final cause.
In the first place, then, the larger the bulk of animals, the greater is the [25] 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 gazelle. But in all our speculations concerning nature, what we have to consider is the general rule; for that is natural which applies either universally or for the most part. Now all the bone in animals’ bodies is earthy; and that is why we [30] can say, if we consider what ho
lds for the most part, that there is most earthy matter in the largest animals. At any rate, in the larger animals there is an excess of it, and this excess is turned by nature to useful account, being converted into weapons of defence. Part of it necessarily flows to the upper portion of the body, and this is allotted in some cases to the formation of tusks and teeth, in others to the formation [35] of horns. Thus it is that no animal that has horns has also front teeth in both jaws, those in the upper jaw being deficient. For nature by subtracting from the teeth [664a1] adds to the horns; the nutriment which in most animals goes to the former being here spent on the augmentation of the latter. Does, it is true, have no horns and yet are equally deficient with the males as regards the teeth. The reason, however, for this is that they, as much as the males, are naturally horn-bearing animals; but they [5] have been stripped of their horns, because these would be useless—indeed they are useless to the males too, but the males’ strength makes them less harmful. In other animals, where this material is not secreted from the body in the shape of horns, it is used to increase the size of the teeth; in some cases of all the teeth, in others merely [10] of the tusks, which thus become so long as to resemble horns projecting from the jaws.
So much, then, of the parts which appertain to the head.
3 · Below the head lies the neck, in such animals as have one. This is the case with those only that have the parts to which a neck is subservient. These parts are [15] the larynx and what is called the oesophagus. Of these the larynx exists for the sake of respiration, being the instrument by which animals inhale and discharge the air. Therefore it is that, when there is no lung, there is also no neck. Of this condition the [20] fishes are an example. The oesophagus is the channel through which food is conveyed to the stomach; so that all animals that are without a neck are also without a distinct oesophagus. Such a part is in fact not required of necessity for nutritive purposes; for it has no action whatsoever on the food. Indeed there is nothing to prevent the stomach from being placed directly after the mouth. This, however, is [25] impossible in the case of the lung. For there must be some sort of tube common to the two divisions of the lung, by which—it being bipartite—the breath may be apportioned to their respective bronchi, and thence pass into the air-pipes; and such an arrangement will be the best for producing inspiration and expiration. The organ then concerned in respiration must of necessity be of some length; and this, again, [30] necessitates there being an oesophagus to unite mouth and stomach. This oesophagus is of a flesh-like character, and yet admits of extension like a sinew. This latter property is given to it, that it may stretch when food is introduced; while the flesh-like character is intended to make it soft and yielding, and to prevent it from [35] being rasped by particles as they pass downwards, and so suffering damage. On the other hand, the windpipe and the so-called larynx are constructed out of a cartilaginous substance. For they have to serve not only for respiration, but also for [664b1] vocal purposes; and an instrument that is to produce sounds must necessarily be not only smooth but firm. The windpipe lies in front of the oesophagus, although this position causes it to be some hindrance to the latter when admitting food. For if a [5] morsel of food, fluid or solid, slips into it by accident, choking and much distress and violent fits of coughing ensue. This must be a matter of astonishment to any of those who assert that it is by the windpipe that an animal imbibes fluid. For the consequences just mentioned occur invariably, whenever a particle of food slips in, [10] and are quite obvious. Indeed on many grounds it is ridiculous to say that this is the channel through which animals imbibe fluid. For there is no passage leading from the lung to the stomach, such as the oesophagus which we see leading thither from the mouth. Moreover, when any cause produces sickness and vomiting, it is plain enough whence the fluid is discharged. It is manifest also that fluid does not pass [15] directly into the bladder and collect there, but goes first into the stomach. For, when red wine is taken, the excreta from the stomach are seen to be coloured by its dregs; and such discoloration has been even seen on many occasions where there have been wounds opening into the stomach. However, it is perhaps silly to be minutely particular in dealing with silly statements such as this.