Aristotle

by Various Works [lit]

  the back than on the under side of the body; whereas in man the

  contrary is the case, and the hair is more abundant on the front

  surface than on the back. The reason for this is that hair is intended

  to serve as a protection to its possessor. Now, in quadrupeds, owing

  to their inclined attitude, the under or anterior surface does not

  require so much protection as the back, and is therefore left

  comparatively bald, in spite of its being the nobler of the two sides.

  But in man, owing to his upright attitude, the anterior and

  posterior surfaces of the body are on an equality as regards need of

  protection. Nature therefore has assigned the protective covering to

  the nobler of the two surfaces; for invariably she brings about the

  best arrangement of such as are possible. This then is the reason that

  there is no lower eyelash in any quadruped; though in some a few

  scattered hairs sprout out under the lower lid. This also is the

  reason that they never have hair in the axillae, nor on the pubes,

  as man has. Their hair, then, instead of being collected in these

  parts, is either thickly set over the whole dorsal surface, as is

  the case for instance in dogs, or, sometimes, forms a mane, as in

  horses and the like, or as in the male lion where the mane is still

  more flowing and ample. So, again, whenever there is a tail of any

  length, nature decks it with hair, with long hair if the stem of the

  tail be short, as in horses, with short hair if the stem be long,

  regard also being had to the condition of the rest of the body. For

  nature invariably gives to one part what she subtracts from another.

  Thus when she has covered the general surface of an animal's body with

  an excess of hair, she leaves a deficiency in the region of the

  tail. This, for instance, in the case with bears.

  No animal has so much hair on the head as man. This, in the first

  place, is the necessary result of the fluid character of his brain,

  and of the presence of so many sutures in his skull. For wherever

  there is the most fluid and the most heat, there also must necessarily

  occur the greatest outgrowth. But, secondly, the thickness of the hair

  in this part has a final cause, being intended to protect the head, by

  preserving it from excess of either heat or cold. And as the brain

  of man is larger and more fluid than that of any other animal, it

  requires a proportionately greater amount of protection. For the

  more fluid a substance is, the more readily does it get excessively

  heated or excessively chilled, while substances of an opposite

  character are less liable to such injurious affections.

  These, however, are matters which by their close connexion with

  eyelashes have led us to digress from our real topic, namely the cause

  to which these lashes owe their existence. We must therefore defer any

  further remarks we may have to make on these matters till the proper

  occasion arises and then return to their consideration.

  15

  Both eyebrows and eyelashes exist for the protection of the eyes;

  the former that they may shelter them, like the eaves of a house, from

  any fluids that trickle down from the head; the latter to act like the

  palisades which are sometimes placed in front of enclosures, and

  keep out any objects which might otherwise get in. The brows are

  placed over the junction of two bones, which is the reason that in old

  age they often become so bushy as to require cutting. The lashes are

  set at the terminations of small blood-vessels. For the vessels come

  to an end where the skin itself terminates; and, in all places where

  these endings occur, the exudation of moisture of a corporeal

  character necessitates the growth of hairs, unless there be some

  operation of nature which interferes, by diverting the moisture to

  another purpose.

  16

  Viviparous quadrupeds, as a rule, present no great variety of form

  in the organ of smell. In those of them, however, whose jaws project

  forwards and taper to a narrow end, so as to form what is called a

  snout, the nostrils are placed in this projection, there being no

  other available plan; while, in the rest, there is a more definite

  demarcation between nostrils and jaws. But in no animal is this part

  so peculiar as in the elephant, where it attains an extraordinary

  and strength. For the elephant uses its nostril as a hand; this

  being the instrument with which it conveys food, fluid and solid

  alike, to its mouth. With it, too, it tears up trees, coiling it round

  their stems. In fact it applies it generally to the purposes of a

  hand. For the elephant has the double character of a land animal,

  and of one that lives in swamps. Seeing then that it has to get its

  food from the water, and yet must necessarily breathe, inasmuch as

  it is a land animal and has blood; seeing, also, that its excessive

  weight prevents it from passing rapidly from water to land, as some

  other sanguineous vivipara that breathe can do, it becomes necessary

  that it shall be suited alike for life in the water and for life on

  dry land. just then as divers are sometimes provided with

  instruments for respiration, through which they can draw air from

  above the water, and thus may remain for a long time under the sea, so

  also have elephants been furnished by nature with their lengthened

  nostril; and, whenever they have to traverse the water, they lift this

  up above the surface and breathe through it. For the elephant's

  proboscis, as already said, is a nostril. Now it would have been

  impossible for this nostril to have the form of a proboscis, had it

  been hard and incapable of bending. For its very length would then

  have prevented the animal from supplying itself with food, being as

  great an impediment as the of certain oxen, that are said to be

  obliged to walk backwards while they are grazing. It is therefore soft

  and flexible, and, being such, is made, in addition to its own

  proper functions, to serve the office of the fore-feet; nature in this

  following her wonted plan of using one and the same part for several

  purposes. For in polydactylous quadrupeds the fore-feet are intended

  not merely to support the weight of the body, but to serve as hands.

  But in elephants, though they must be reckoned polydactylous, as their

  foot has neither cloven nor solid hoof, the fore-feet, owing to the

  great size and weight of the body, are reduced to the condition of

  mere supports; and indeed their slow motion and unfitness for

  bending make them useless for any other purpose. A nostril, then, is

  given to the elephant for respiration, as to every other animal that

  has a lung, and is lengthened out and endowed with its power of

  coiling because the animal has to remain for considerable periods of

  time in the water, and is unable to pass thence to dry ground with any

  rapidity. But as the feet are shorn of their full office, this same

  part is also, as already said, made by nature to supply their place,

  and give such help as otherwise would be rendered by them.

  As to other sanguineous animals, the Birds, the Serpe
nts, and the

  Oviparous quadrupeds, in all of them there are the nostril-holes,

  placed in front of the mouth; but in none are there any distinctly

  formed nostrils, nothing in fact which can be called nostrils except

  from a functional point of view. A bird at any rate has nothing

  which can properly be called a nose. For its so-called beak is a

  substitute for jaws. The reason for this is to be found in the natural

  conformation of birds. For they are winged bipeds; and this makes it

  necessary that their heads and neck shall be of light weight; just

  as it makes it necessary that their breast shall be narrow. The beak

  therefore with which they are provided is formed of a bone-like

  substance, in order that it may serve as a weapon as well as for

  nutritive purposes, but is made of narrow dimensions to suit the small

  size of the head. In this beak are placed the olfactory passages.

  But there are no nostrils; for such could not possibly be placed

  there.

  As for those animals that have no respiration, it has already been

  explained why it is that they are without nostrils, and perceive

  odours either through gills, or through a blowhole, or, if they are

  insects, by the hypozoma; and how the power of smelling depends,

  like their motion, upon the innate spirit of their bodies, which in

  all of them is implanted by nature and not introduced from without.

  Under the nostrils are the lips, in such sanguineous animals, that

  is, as have teeth. For in birds, as already has been said, the

  purposes of nutrition and defence are fulfilled by a bonelike beak,

  which forms a compound substitute for teeth and lips. For supposing

  that one were to cut off a man's lips, unite his upper teeth together,

  and similarly his under ones, and then were to lengthen out the two

  separate pieces thus formed, narrowing them on either side and

  making them project forwards, supposing, I say, this to be done, we

  should at once have a bird-like beak.

  The use of the lips in all animals except man is to preserve and

  guard the teeth; and thus it is that the distinctness with which the

  lips are formed is in direct proportion to the degree of nicety and

  perfection with which the teeth are fashioned. In man the lips are

  soft and flesh-like and capable of separating from each other. Their

  purpose, as in other animals, is to guard the teeth, but they are more

  especially intended to serve a higher office, contributing in common

  with other parts to man's faculty of speech. For just as nature has

  made man's tongue unlike that of other animals, and, in accordance

  with what I have said is her not uncommon practice, has used it for

  two distinct operations, namely for the perception of savours and

  for speech, so also has she acted with regard to the lips, and made

  them serve both for speech and for the protection of the teeth. For

  vocal speech consists of combinations of the letters, and most of

  these would be impossible to pronounce, were the lips not moist, nor

  the tongue such as it is. For some letters are formed by closures of

  the lips and others by applications of the tongue. But what are the

  differences presented by these and what the nature and extent of

  such differences, are questions to which answers must be sought from

  those who are versed in metrical science. It was necessary that the

  two parts which we are discussing should, in conformity with the

  requirements, be severally adapted to fulfil the office mentioned

  above, and be of appropriate character. Therefore are they made of

  flesh, and flesh is softer in man than in any other animal, the reason

  for this being that of all animals man has the most delicate sense

  of touch.

  17

  The tongue is placed under the vaulted roof of the mouth. In land

  animals it presents but little diversity. But in other animals it is

  variable, and this whethe+r we compare them as a class with such as

  live on land, or compare their several species with each other. It

  is in man that the tongue attains its greatest degree of freedom, of

  softness, and of breadth; the object of this being to render it

  suitable for its double function. For its softness fits it for the

  perception of savours, a sense which is more delicate in man than in

  any other animal, softness being most impressionable by touch, of

  which sense taste is but a variety. This same softness again, together

  with its breadth, adapts it for the articulation of letters and for

  speech. For these qualities, combined with its freedom from

  attachment, are those which suit it best for advancing and retiring in

  every direction. That this is so is plain, if we consider the case

  of those who are tongue-tied in however slight a degree. For their

  speech is indistinct and lisping; that is to say there are certain

  letters which they cannot pronounce. In being broad is comprised the

  possibility of becoming narrow; for in the great the small is

  included, but not the great in the small.

  What has been said explains why, among birds, those that are most

  capable of pronouncing letters are such as have the broadest

  tongues; and why the viviparous and sanguineous quadrupeds, where

  the tongue is hard and thick and not free in its motions, have a

  very limited vocal articulation. Some birds have a considerable

  variety of notes. These are the smaller kinds. But it is the birds

  with talons that have the broader tongues. All birds use their tongues

  to communicate with each other. But some do this in a greater degree

  than the rest; so that in some cases it even seems as though actual

  instruction were imparted from one to another by its agency. These,

  however, are matters which have already been discussed in the

  Researches concerning Animals.

  As to those oviparous and sanguineous animals that live not in the

  air but on the earth, their tongue in most cases is tied down and

  hard, and is therefore useless for vocal purposes; in the serpents,

  however, and in the lizards it is long and forked, so as to be

  suited for the perception of savours. So long indeed is this part in

  serpents, that though small while in the mouth it can be protruded

  to a great distance. In these animals it is forked and has a fine

  and hair-like extremity, because of their great liking for dainty

  food. For by this arrangement they derive a twofold pleasure from

  savours, their gustatory sensation being as it were doubled.

  Even some bloodless animals have an organ that serves for the

  perception of savours; and in sanguineous animals such an organ is

  invariably variably For even in such of these as would seem to an

  ordinary observer to have nothing of the kind, some of the fishes

  for example, there is a kind of shabby representative of a tongue,

  much like what exists in river crocodiles. In most of these cases

  the apparent absence of the part can be rationally explained on some

  ground or other. For in the first place the interior of the mouth in

  animals of this character is invariably spinous. Secondly, in water

  animals there is but short space of time fo
r the perception of

  savours, and as the use of this sense is thus of short duration,

  shortened also is the separate part which subserves it. The reason for

  their food being so rapidly transmitted to the stomach is that they

  cannot possibly spend any time in sucking out the juices; for were

  they to attempt to do so, the water would make its way in during the

  process. Unless therefore one pulls their mouth very widely open,

  the projection of this part is quite invisible. The region exposed

  by thus opening the mouth is spinous; for it is formed by the close

  apposition of the gills, which are of a spinous character.

  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, on this

  animal is not attached to the upper jaw, because that would

  interfere with the 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.

  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 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, as the gustatory

  sensibility is intended to serve animals in the selection of food,

  it 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