Aristotle · a new plain-English translation from the original language
1| History of Animals, Book 1. Of the parts found in animals, some are non-composite — those that divide into parts alike in kind, as flesh divides into flesh — while others are composite — those that divide into parts unlike in kind, as the hand does not divide into hands, nor the face into faces. Of parts of the latter kind, some are called not only parts but also limbs. Such are those that, being themselves whole parts, contain within themselves other parts — for example the head, the leg, the hand, the whole arm, and the chest; for these are themselves whole parts, and there are other parts within them. Now all the parts unlike in kind are composed out of the parts alike in kind — for example the hand out of flesh and sinews and bones. Some animals have all their parts the same as one another, others have different parts. Of parts that are the same, some are the same in form — for example a human's nose and eye are the same in form as another human's nose and eye, and flesh is the same as flesh, bone as bone; and the same holds for the horse and the other animals that we say are the same as themselves in form, for as the whole stands to the whole, so each of the parts stands to each. Other parts are the same, but differ by excess and deficiency, wherever the genus is the same for both.
2| By genus I mean, for example, bird and fish; for each of these has a differentia proper to its genus, and there are several species of fish and of birds. Most of the parts differ among themselves owing to the opposition of their affections — for example of color and of shape — in that some are more affected in this way and others less, and further by superiority and inferiority in number, and in largeness and smallness, and in general by excess and deficiency. For some of these animals have soft flesh and others hard flesh, and some have a long beak and others a short one, and some have many feathers and others few. Yet even among these, some have parts that others lack — for example some have spurs and others do not, and some have a crest and others do not. But speaking generally, most of the parts, and indeed the parts out of which the whole bulk is composed, are either the same or differ by their opposites, that is by excess and deficiency; for the more and the less one might class as a kind of excess and deficiency. Some animals, however, have parts that are neither the same in form nor differing by excess and deficiency, but analogous — as bone stands to fish-spine, and claw to hoof, and hand to pincer, and scale to feather;
3| for what feather is in a bird, that scale is in a fish. So then, with respect to the parts that each of the animals has, they are different and the same in this way, and further in the position of the parts; for many animals have the same parts, but not placed in the same way — for example some have their breasts on the chest, others near the thighs. Of the parts alike in kind, some are soft and moist, others dry and solid. Moist — either altogether, or for as long as they remain in their natural state — are, for example, blood, serum, lard, suet, marrow, seed, bile, milk in those that have it, flesh and what is analogous to it in other animals, and further, in another way, the residues, such as phlegm, and the sediments of the stomach and of the bladder. Dry and solid are, for example, sinew, skin, vein, hair, bone, cartilage, claw, horn (for "horn" is used equivocally as applied to the genus, whenever the whole is also called horn from its shape), and further whatever is analogous to these. The differentiae among animals lie in their modes of life, their activities, their characters, and their parts; about these let us first speak in outline, and afterward, giving attention to each genus in turn, we shall speak of them individually.
4| The differentiae with respect to modes of life, characters, and activities are of the following sort. Some animals are aquatic, others live on land; and aquatic animals are so in two ways: some, because they pass their life and take their nourishment in the water, and take in water and let it out, and cannot live if deprived of this — as happens with many fish; others take their nourishment and spend their time in the water, yet do not take in water but air, and give birth outside the water. Many such animals are also land-dwelling, like the otter, the beaver, and the crocodile, and some are winged, like the diver-bird and the grebe, and some are footless, like the water-snake. Some take their nourishment in the water and cannot live outside it, yet take in neither air nor water — for example the sea-nettle and the shellfish. Of aquatic animals, some are marine, some river-dwelling, some lake-dwelling, some marsh-dwelling, like the frog and the tadpole. Of land animals, some take in air and let it out, which is called breathing in and breathing out — for example man and all land animals that have lungs;
5| others do not take in air at all, yet live and get their nourishment on land — for example the wasp, the bee, and the other insects. I call insects those that have notches along the body, either on the underside, or on both the underside and the upper side. And of land animals many, as has been said, procure their nourishment from the water, while of aquatic animals — even those that take in the sea — none procures nourishment from the land. Some animals live at first in water, then change into another form and live outside it, as happens with the gnats found in rivers; for the gadfly is generated from these. Further, some animals are stationary, others capable of movement; and the stationary ones are found in water — none of the land animals is stationary. In water many live by being attached, like many kinds of shellfish. The sponge too seems to have some perception; the sign of this is that it is harder to tear away, they say, unless the disturbance is made stealthily. Some are both attached and detached, as is a certain kind of the so-called sea-nettle; for some of these detach themselves at night and go about feeding.
6| Many are detached yet motionless, like the shellfish and the so-called sea-cucumbers. Others are swimmers, like fish and the cephalopods and the crustaceans, such as the crayfish. Others are walkers, like the crab kind; for this, though aquatic in nature, is a walker. Of land animals, some are winged, like birds and bees, and these differ from one another in their manner of flight, and others are footed. And of the footed ones, some are walkers, some crawlers, some wrigglers. Nothing is winged only, just as no fish is a swimmer only; for even the leather-winged creatures walk on the ground, and the bat has feet, and the seal has stunted feet. And among birds there are some poor-footed ones, which for this reason are called "footless"; this little bird is well-feathered. And nearly all birds resembling it are well-feathered but poor-footed, like the swallow and the swift; for all these are alike in habits and alike in wing, and their appearances are close to one another. The footless one appears at every season, but the swift when it rains in summer; for then it is seen and caught, and in general this bird is rare. Many animals are both walkers and swimmers.
7| There are also differences of the following kind, in ways of life and activities. Some animals are gregarious, others solitary, and some are land-dwelling, others winged, others swimming, while others live in both ways. And among both the gregarious and the solitary, some are political and some are scattered. Gregarious, for example, among the winged, are the pigeon family, the crane, and the swan (no hook-taloned bird is gregarious), and among swimming creatures many kinds of fish, such as those they call runners — tunny, pelamyds, amiae. Man lives in both ways. Political animals are those for which some single common task arises for all — which not all gregarious animals do. Man is such, and so is the bee, the wasp, the ant, the crane. And of these, some live under a leader, others without a ruler: the crane, for instance, and the bee family live under a leader, while ants and countless others have no ruler. Some, whether gregarious or solitary, stay at home, others migrate. Some are flesh-eating, some fruit-eating, some omnivorous, and some feed on a special diet of their own, like the bee family and the spider family: bees live on honey and a few other sweet things, spiders live by hunting flies, while others feed on fish.
8| Some are hunters, some are food-storers, others not. Some make dwellings, others are homeless: dwelling-makers, for example, are the mole, the mouse, the ant, the bee, while many insects and four-footed creatures are homeless. Again, by location, some are burrowers, like the lizard and the snake, others live above ground, like the horse and the dog. Some are hole-dwellers, others not. Some are night-active, like the owl and the bat, others live in the light. Again, some are tame and some are wild, and some are always so: man and the mule are always tame, others are always wild, like the leopard and the wolf; others again can be tamed quickly, like the elephant. And yet in another sense: all the kinds that are tame also occur wild, for example horses, cattle, pigs, sheep, goats, dogs. Some are noisy, others voiceless, others vocal, and of these some have a distinct call while others are inarticulate, and some are chattering, others silent, some are song-birds, others not; but it is common to all that they sing and call most around mating time. Some are creatures of open country, like the wood-pigeon, others of the mountains, like the hoopoe, and others live alongside man, like the domestic pigeon.
9| Some are highly sexual, like the partridge and the cock family, others are chaste, like the crow family of birds — these mate rarely. Among sea creatures, some live in the open sea, some near the shore, some among rocks. Again, some are defensive, others merely watchful: defensive are those that either attack or, when wronged, fight back; watchful are those that have within themselves a means of escaping harm without fighting. They also differ in the following ways of character. Some are gentle, low-spirited, and unaggressive, like the ox; others are spirited, aggressive, and unintelligent, like the wild pig; others are prudent and timid, like the deer and the hare; others are ignoble and treacherous, like snakes; others are noble-spirited, courageous, and well-bred, like the lion; others are high-born yet wild and treacherous, like the wolf — for well-bred means coming from a good stock, while noble-spirited means not departing from one's own nature. Some are cunning and mischievous, like the fox; some are spirited, affectionate, and fawning, like the dog; some are gentle and easily tamed, like the elephant; some are bashful and watchful, like the goose; some are jealous and lovers of beauty, like the peacock.
10| Man alone among animals is capable of deliberation. Many animals share in memory and in being taught, but none besides man can recollect. The characters and ways of life belonging to each kind will be discussed later in greater detail. All animals have in common the parts by which they take in food and the part into which they take it; and these are the same or different in the ways already stated — differing in species, in degree, by analogy, or in position. Beyond these, most animals have further common parts, namely that by which they expel the residue of their food and that by which they take it in — for this is not present in all. What takes it in is called the mouth, what receives it is called the stomach; the rest goes by many names. Since the residue is of two kinds, whatever has parts receptive of the moist residue also has parts for the dry food, but not all that have the latter have the former. Hence whatever has a bladder also has a stomach, but not all that have a stomach have a bladder. For the part receptive of the moist residue is called the bladder, and that of the dry residue the stomach.
11| Of the remaining parts, many animals also have those by which they emit seed; and among these, in those where generation of animals occurs, one emits into itself, the other into another. What emits into itself is called female, what emits into this is called male. In some there is no male and female; and here too the form of the parts serving this function differs — some have a uterus, others what is analogous to it. These, then, are the most necessary parts, some belonging to all animals, others to most. All animals have one perception in common, and only one: touch. Hence the part in which this naturally occurs has no name — for in some it is the same organ, in others what is analogous to it.
12| Every animal also has moisture, deprived of which, whether by nature or by force, it perishes. Further, there is that in which this moisture arises, and this is a further thing: in some it is blood and vein, in others what is analogous to these; and in some these are incomplete, as with one animal it is fibrous fluid, with another ichor. Touch, then, occurs in a uniform part, such as flesh or something of that kind, and in general in blooded creatures, wherever they have blood; in the others it occurs in the analogous part, but in all of them it occurs in the uniform parts. The functional capacities, on the other hand, occur in the non-uniform parts — for example the working of food occurs in the mouth, and locomotion in feet or wings or their analogues. Beyond this, some animals are blooded, such as man and the horse and all that, when mature, are footless, or two-footed, or four-footed; others are bloodless, such as the bee and the wasp, and among sea creatures the cuttlefish and the crayfish and all that have more than four feet.
13| Some animals bear live young, others lay eggs, others produce larvae. Live-bearers are, for example, man and the horse and the seal and all the others that have hair, and among water creatures the whale-kind, such as the dolphin, and the so-called cartilaginous fish. Of these, some have a blowhole and no gills, like the dolphin and the whale (the dolphin has its blowhole through its back, the whale on its forehead), others have uncovered gills, like the cartilaginous fish, the dogfish and the rays. Among complete conceptions, that is called an egg from which the animal that comes to be is generated, beginning from one part, while the rest serves as nourishment for what is being formed; a larva is that from which the whole animal comes to be from the whole, the conception being articulated and growing as a whole. Of the live-bearers, some lay eggs within themselves, like the cartilaginous fish, others bear live young within themselves, like man and the horse; and into the visible world, in some cases, once the conception is complete, an animal emerges, in others an egg, in others a larva. Of eggs, some are hard-shelled and two-colored, like those of birds, others are soft-shelled and single-colored, like those of the cartilaginous fish.
14| Among grubs, too, some are motile from the start and others are not. But about these we will speak with precision later, in the works on generation. Further, of animals some have feet and some are footless; and of those with feet, some have two feet, as man and birds alone, some have four, as the lizard and the dog, and some have more, as the centipede and the bee; but all have an even number of feet. Of the swimming animals, those without feet have fins, as fish do, and of these some have four fins, two above on the upper side and two below on the underside, as the gilthead and the bass, while others have only two, namely those that are elongated and smooth, as the eel and the conger; others have none at all, as the moray and any others that use the sea the way snakes use land, and they swim through the water in the same fashion. Of the cartilaginous fish, some have no fins at all, namely the flat, tail-bearing ones, as the ray and the sting-ray, but these swim with their flat bodies themselves; the fishing-frog, however, does have fins, as do all those whose flatness is not extreme. As for those that appear to have feet, as the soft-bodied creatures do, these swim with their fins as well, and move faster tail-first, as the cuttlefish, the squid, and the octopus;
15| but neither of these actually walks, no more than the octopus does. The hard-shelled creatures, as the crayfish, swim with their tail-parts, and move fastest tail-first, by means of the fins on that part; and the crab-fry swims with its feet and its tail-part, having a tail-part like the sheat-fish's, small compared to large, so to speak. Of the winged creatures, some are feathered, as the eagle and the hawk, some are plumed, as the bee and the cockchafer, and some have skin-wings, as the fox-bat and the bat. Now those that are feathered are all blooded creatures, and likewise those with skin-wings; those that are plumed are all bloodless, as the insects. The feathered and the skin-winged are all either two-footed or footless; for there are said to be certain snakes of this sort around Ethiopia. Now the feathered class of animals is called bird, while the other two classes have no single name of their own. Of the winged but bloodless creatures, some are sheath-winged (for they keep their wings inside a sheath, as the cockchafers and the dung-beetles), and others have no sheath; and of these latter some are two-winged, others four-winged — four-winged whichever have some size or have their sting at the rear, two-winged whichever lack size or have their sting at the front. None of the sheath-winged creatures has a sting.
16| The two-winged creatures have their stings at the front, as the fly, the horse-fly, the gadfly, and the gnat. All the bloodless creatures are smaller in size than the blooded ones, except that a few bloodless creatures in the sea are larger, as some of the soft-bodied kind. These classes grow largest in the warmest regions, and more so in the sea than on land, and in fresh waters as well. Everything that moves, moves by means of four points or more: the blooded creatures by four only, as man with two hands and two feet, the bird with two wings and two feet, and the four-footed creatures and fishes, the former with four feet and the latter with four fins. As for those that have only two fins or none at all, as the snake, they move no less by four points; for its bends are four, or two together with the fins. But such bloodless creatures as have more feet, whether winged or land-going, move by more points, as the creature called the day-fly does, by four feet and wings; for this creature is remarkable not only in its manner of life, from which it gets its name, but also in that, though it is winged, it is also four-footed.
17| All creatures move alike, the four-footed and the many-footed; for they move on the diagonal. Now the other animals have two feet that lead, but the crab alone of animals has four. The greatest classes of animals, into which the rest of the animals are divided, are these: one of birds, one of fishes, another of cetaceans. All of these, then, are blooded. Another class is that of the hard-shelled creatures, which is called the oyster kind; another is that of the soft-shelled creatures, which has no single name, as the crayfish and certain classes of crabs and lobsters; another is that of the soft-bodied creatures, as the squids and the calamaries and the cuttlefish; and a further one is that of the insects. All of these are bloodless, and whichever of them have feet are many-footed; and some of the insects are winged as well. Of the remaining animals the classes are no longer large; for a single class does not embrace many species, but in some cases the species itself is simple, having no differentia, as man, while in others it does have differentiae, but the species are nameless. For the four-footed, non-winged creatures are all blooded, but some of them bear their young alive and others lay eggs. Now whichever bear their young alive do not all have hair, and whichever lay eggs have scales; and the scale is something like a strip of the horny plate. The class of snakes is by nature bloodless — footless and land-going; and this class is scaly.
18| But whereas the other snakes lay eggs, the viper alone bears its young alive. For not all live-bearing creatures have hair; indeed some fishes too bear their young alive; yet whichever have hair all bear their young alive. For one must reckon as a kind of hair the spine-like hairs too, such as land hedgehogs and porcupines have; for these serve the purpose of hair, not of feet, unlike those of the sea-creatures. Of the class of four-footed, live-bearing animals there are many species, but they are nameless; still, taken one by one, so to speak, just as man has been named, so too lion, deer, horse, dog, and the rest in this same way — since there is a single class as well in the case of the so-called tufted-tail animals, as the horse and the ass and the mule and the hinny and the jenny and the creatures called in Syria half-asses, which are called half-asses on account of resemblance, though they are not simply the same species; for indeed they mate with one another and produce offspring from one another. For this reason one must, even when taking them separately, examine the nature of each of them.
19| These things, then, have now been stated in this manner in outline, by way of a taste, for the sake of showing about how many and what sort of things one must inquire; we will speak with precision later, so that we may first grasp the differentiae that belong to them and the attributes that belong to all. After this one must try to find the causes of these things. For it is natural to conduct the inquiry in this way, once the descriptive history concerning each animal is available; for it becomes clear from these what the demonstration ought to be about and out of what it ought to be built. One must first take up the parts of animals, out of which they are composed. For it is chiefly and primarily in respect of these that wholes differ as well, either by having some parts and not having others, or by position and arrangement, or according to the differentiae stated earlier — in form, in degree, in ratio, and in the opposition of their affections. First one must take up the parts of man; for just as everyone tests coinage by reference to what is most familiar to himself, so too in other matters; and man is necessarily the animal most familiar to us. Now the parts are not unclear to perception; still, for the sake of not omitting what comes next in order, and of having an account to go along with perception, one must state the parts, first the organic ones, then the uniform ones.
20| These, then, are the largest parts into which the body as a whole is divided: head, neck, chest, two arms, two legs, and the cavity from the neck to the genitals, which is called the thorax. Of the head, the part covered with hair is called the skull. Of this, the front part is the bregma, which comes into being last (for it is the last of the bones in the body to harden), the back part is the inion, and the part between the inion and the bregma is the crown. Under the bregma is the brain, but the inion is empty. The whole skull is a porous, rounded bone, covered by fleshless skin. It has sutures — in women, one running in a circle, in men, as a rule, three meeting at one point; but a man's head has before now been seen with no suture at all. The middle of the skull, where the hair lies smooth, is called the crown. In some people this is double, for some are born with two crowns — not from a double bone, but from the way the hair lies smooth in two places. The part under the skull is called, only in the case of man among the other animals, the face; for one does not speak of the face of a fish or an ox. Of the face, the part under the bregma between the eyes is the forehead. In those in whom this is large, people are slower; in those in whom it is small, quick to move; and in those in whom it is broad, given to distraction; in those in whom it is rounded, quick-tempered.
21| Under the forehead are the two eyebrows. Of these, straight ones are a sign of a soft character; those curving down toward the nose, of a harsh one; those curving toward the temples, of a mocking and dissembling character; those drawn down, of envy. Under the eyebrows are the eyes. These are naturally two in number. Each of them has parts, the upper and lower eyelid. Of the eyelid, the outermost hairs are the eyelashes. Of the inside of the eye, the moist part with which it sees is the pupil, the part around this is the black, and the part outside that is the white. The part of the eyelid shared by the upper and lower is the two corners, one toward the nose and one toward the temples; if these are long, it is a sign of ill nature, and if, as in the case of combs, they have flesh toward the nostril, of wickedness. Now all the other kinds of animals, except the testaceans and any other incomplete kind, have eyes; and all the live-bearing animals have them, except the mole. This animal one might posit as having them in a certain way, yet as wholly without them. For it wholly neither sees nor has eyes visible in the open; but once the skin is stripped away, it has both the place where the eyes should be and, in that region, the black parts of the eyes, and the space that by nature belongs to eyes on the outside — as if in its formation the eyes had been stunted and the skin had grown over them.
22| Of the eye, the white is much alike in all animals, but the so-called black part differs: in some it is black, in others quite grey-blue, in others light blue, and in some goat-eyed, which is a sign of the best character and is strongest for sharpness of vision. Man alone, or man most of all among animals, has eyes of many colors; the other animals each have one kind. Horses, though, are sometimes born grey-blue-eyed. Of eyes, some are large, some small, some middling; the middling are best. And eyes are set either quite prominent, or sunken, or in between; of these, the sunken are the sharpest-sighted in every animal, while the middling is a sign of the best character. And eyes are either given to blinking, or fixed and staring, or in between; the middling is a sign of the best character, while of the other two, the one is a sign of shamelessness, the other of instability.
23| Further, there is a part of the head through which one hears, without breath passing through it, the ear; for Alcmaeon is not speaking the truth when he says that goats breathe through their ears. Of the ear, one part has no name, the other is the lobe. The whole is composed of cartilage and flesh. On the inside its nature is like that of spiral shells, and at its innermost end there is a bone resembling the ear itself, into which, as into a final vessel, sound arrives. This bone has no passage into the brain, but does have one into the roof of the mouth; and a vein stretches from the brain to it. The eyes too terminate in the brain, and each of them lies upon a small vein. Man alone among the animals possessing this part has an immovable ear. For of the animals possessing hearing, some have ears and some do not, but instead have the passage exposed, as do all that are feathered or scaly. All that are live-bearing have ears, except the seal and the dolphin and the other whale-like creatures of that kind — for the cartilaginous fish too are live-bearing — but man alone does not move his ears. Now the seal has visible passages by which it hears; the dolphin hears, but has no ears.
24| All the other animals move their ears. The ears are set on the same circumference as the eyes, and not, as in some of the four-footed animals, above them. Of ears, some are bare, some hairy, some in between; the in-between are best for hearing, but signify nothing about character. And ears are either large or small or middling, or standing up very much, or not at all, or in between; the middling are a sign of the best character, while large ears that stand up are signs of foolish talk and idle chatter. The part between the eye, the ear, and the crown is called the temple. Further, of the face, the passage for the breath is the nose; for one both breathes in and breathes out through it, and a sneeze occurs through it — a sudden discharge of breath, and the only one of the breaths that is taken as an omen and held sacred. Breathing in and breathing out occur at the same time as movement toward the chest, and it is impossible to breathe in or out through the nostrils apart from this, because breathing in and out proceed from the chest by way of the uvula, and not from some part of the head; but it is possible to live without making use of this passage. Smelling occurs through this part; and this is the perception of odor.
25| The nostril is easily moved, and not, like the ear, immovable on its own. One part of it is the cartilage that divides it, the other the hollow channel; for the nostril is split in two. In elephants the nose becomes long and strong, and the animal uses it like a hand; for with it the elephant draws things to itself and takes hold of them, and brings food, both wet and dry, to its mouth — the only animal to do so. Further, there are two jaws; of these, the front one is the chin, the back one the jaw proper. All animals move the lower jaw, except the river crocodile; this one moves only the upper. After the nose come the two lips, easily moved flesh. The mouth is the interior enclosed by the jaws and lips. Of this, one part is the palate, the other the pharynx. The organ that perceives flavor is the tongue; the perception occurs at its tip, and if a flavor is placed on the flat part, it is felt less. It also perceives everything that the rest of the flesh perceives, such as hard, hot, and cold in any part whatsoever, just as it perceives flavor. The tongue is either broad or narrow or middling; the middling is best and clearest. And it is either loose or bound down, as in the case of the lisping and the stammering.
26| The tongue is flesh that is loose and spongy. A part of it is the epiglottis. The double-formed part of the mouth is the tonsil, the multiply-formed part is the gum; these are fleshy. Inside are the teeth, made of bone. Within is another part that bears the uvula, a vein-covered pillar; if this becomes moist and inflamed, it is called the uvula, and it chokes. The neck is what lies between the face and the chest. Of this, the front part is the larynx, the back part is the gullet. Of the larynx, the cartilaginous and forward part, through which voice and breath pass, is the windpipe; the fleshy part is the gullet, lying inside in front of the spine. The back part of the neck is the point of the shoulder. These, then, are the parts as far as the chest. Of the chest, some parts are in front, some behind. First, after the neck, in the front parts, is the breast, double because of the two breasts. Of these the nipple is double, through which milk filters in females; the breast itself is loose in texture. Milk also forms in males; but the flesh is dense in males, while in women it is spongy and full of passages.
27| After the chest, in the front parts, is the belly, and its root is the navel. Below its root, the part that is double is the flank; the part that is single is, below the navel, the abdomen (the lowest part of this is the pubic region), and above the navel is the hypochondrium; the part common to the hypochondrium and the flank is the flank-hollow. Of the parts behind, the loin is the girding band, from which it also gets its name (for it seems to be of uniform growth throughout); of the region of motion, the part that serves as a kind of seat is the buttock, and the part in which the thigh turns is the hip-socket. The part peculiar to the female is the womb, and to the male the genitals, on the outside at the end of the trunk, in two parts: the tip, which is fleshy and smooth and, one might say, uniform, is called the glans; the skin around it has no name of its own, and if it is cut through it does not grow back together, any more than the cheek or the eyelid does. Common to this skin and to the glans is the foreskin. The remaining part is cartilaginous and grows readily, and it goes out and comes in in the opposite way to the case of tufted-tailed animals. Below the genitals are the two testicles. The skin around them is called the scrotum. The testicles are neither identical with flesh nor far removed from flesh; how they are constituted will be stated later in detail, in general, concerning all parts of this kind.
28| The genitals of the woman are the opposite of those of men: for the part below the pubic bone is hollow, and not, as in the male, projecting outward. And the urethra lies outside the womb, a passage for the male's semen, and an outlet for the liquid residue of both. The part common to the neck and the chest is the throat-hollow; common to the ribs, the upper arm, and the shoulder is the armpit; common to the thigh and the abdomen is the groin. The inner part common to the thigh and the buttock is the perineum; the outer part common to the thigh and the buttock is the under-buttock. Concerning the front parts of the trunk enough has been said; the back part of the chest is the back.
29| The parts of the back are the two shoulder-blades and the spine, and below, level with the belly of the trunk, is the loin. Common to the upper and lower parts are the ribs, eight on each side; for as regards the Ligurians said to have seven ribs, we have not yet heard anything trustworthy on the matter. A human being has both an upper and a lower part, front and back parts, and right and left parts. Now the right and left parts are nearly alike in their divisions and the same in all respects, except that the left side is weaker; but the back parts are unlike the front, and the lower unlike the upper, except in this respect, that they are alike: the parts below the abdomen resemble the face in fleshiness and leanness, and the legs stand opposite the arms; and those whose elbows are short generally also have short thighs, and those whose feet are small also have small hands. Of the limb, the double-jointed part is the upper arm; of the upper arm, the parts are the shoulder, the elbow, the point of the elbow, the forearm, and the hand; of the hand, the palm and five fingers; of the finger, the bending part is the knuckle, the unbending part is the joint-bone. Of the fingers, the thumb has one knuckle, the rest have two. The bending, both of the arm and of the finger, is inward in every case;
30| and the upper arm bends at the point of the elbow. Of the hand, the inner part is the palm, fleshy and divided by joint-lines — in the long-lived, by one or two lines running all the way across, in the short-lived, by two lines that do not run all the way across. The joints of the hand and the arm form the wrist. The outer part of the hand is sinewy and has no name. Of the limb, the leg is another two-part member. Of the leg, the part with two rounded ends is the thigh; the part that shifts about in its seat is the kneecap; the part with two bones is the shin, of which the front part is the shin proper and the back part is the calf — flesh that is sinewy or full of veins, drawn up toward the ham in those who have large hips, and in others drawn down the opposite way. The end of the shin is the ankle, which is double on each leg. The part of the leg with many bones is the foot. Of this, the back part is the heel, and of the front of the foot, the part split into five is the toes; the fleshy part underneath is the ball, and the part above, on the upper surface, is sinewy and has no name. Of the toe, one part is the nail, the other the joint; in all cases the nail is at the tip; all the lower toes bend in only one direction. Those whose foot is thick on the inside and not hollow, but who walk on the whole of it, are cunning.
31| Common to the thigh and the shin is the knee, the bending-point. These, then, are the parts common to both male and female. As for the position of the parts with respect to up and down, front and back, right and left, this might seem to be obvious to perception simply by looking at the outside; nevertheless it must be stated, for the same reason we stated the earlier matters, so that what follows may be carried through, and so that, in enumerating them, those cases that do not follow the same pattern — both among the other animals and among human beings — may be less likely to escape notice. The human being, more than the other animals, has up and down clearly marked off with reference to their natural places; for in humans, up and down correspond to the up and down of the universe as a whole. In the same way front and back, and right and left, are also disposed according to nature. Of the other animals, some do not have this distinction at all, while others have it, but in a more confused way. In every animal, the head is 'up' with reference to that animal's own body; but the human being alone, as has been said, has this part positioned with reference to what is 'up' for the whole universe, since he alone has reached completion in this respect.
32| After the head comes the neck, then the chest and the back, the one in front, the other behind. Next after these come the belly, the loin, the genitals, and the hip, then the thigh and the shin, and last the feet. The legs bend toward the front, in the direction of forward motion, and the more mobile part of the foot, along with its bend, is likewise forward; the heel is behind; and each of the anklebones is level with the ear. From the sides, right and left, come the arms, bending inward, so that the convex sides of the legs and of the arms face one another most of all in the human being. The senses and their organs — the eyes, the nostrils, and the tongue — are set in the same region, facing forward; but hearing, its organ, and the ears are set to the side, though on the same circumference as the eyes. In humans, the eyes are separated by the smallest distance relative to their size of any animal. Of the senses, the human being has touch as the most precise, and taste second; but in the rest he falls short of many animals.
33| The parts on the outer surface, then, are arranged in this way, and, as was said, are for the most part named and familiar to us because we are used to them; the internal parts are the opposite. For the internal parts of human beings are the least known of all, so that we must study them by referring to the parts of the other animals, whose nature is similar. First, then, the brain is positioned toward the front of the head. This holds likewise for the other animals that have this part; and all blooded animals have it, and so do the cephalopods too. In proportion to size, the human being has the most brain and the moistest. Two membranes surround it: the one around the bone is stronger, the one around the brain itself is weaker than that one. In all animals the brain is double in nature. And at the rear of it is what is called the cerebellum, which has a different shape both to the touch and to sight. The back part of the head is empty and hollow in all, in proportion to each animal's size. Some animals have a large head but a smaller portion of face beneath it — those that are round-faced;
34| while others have a small head but long jaws, as is true of the whole tribe of crested animals. In all animals the brain is bloodless, containing no vein within itself, and cold to the touch by nature. In most animals it has some small hollow in its middle. The membrane around it is veined; this membrane, the one enclosing the brain, is a skin-like tissue. Above the brain is the thinnest and weakest bone of the head, which is called the bregma. Three passages lead from the eye to the brain: the largest and the middle one lead to the cerebellum, and the smallest to the brain itself; the smallest is the one nearest the nostril. The largest passages lie alongside one another and do not meet, while the middle ones do meet (this is most evident in fish); for these lie nearer to the brain than the large ones do; but the smallest are furthest apart from one another and do not meet. Within the neck is what is called the esophagus, named from its length and narrowness, and also the windpipe. The windpipe is positioned, in all animals that have it, in front of the esophagus;
35| and every animal that has a lung has this windpipe too. The windpipe is cartilaginous in nature and has little blood, being surrounded by many thin small veins; it lies, toward the upper part, against the mouth, at the perforation running from the nostrils into the mouth — the passage by which, when people draw up some of their drink while drinking, it goes out from the mouth through the nostrils. Between these openings it has what is called the epiglottis, which is able to fold down over the opening of the windpipe that stretches toward the mouth. The tip of the tongue is joined to this. On the other side it descends to the space between the lungs, and from there it splits toward each of the two parts of the lung. For the lung tends to be two-parted in all animals that have one; but in the live-bearing animals the division is not equally evident, and least of all in the human being. The human lung is not much-divided, as it is in some live-bearing animals, nor is it smooth, but has an unevenness. In the egg-laying animals, such as birds and those four-footed animals that lay eggs, each part is split far apart from the other, so that the animal seems to have two lungs; and from one windpipe there are two divisions, each stretching to its own part of the lung.
36| It is also joined to the great vein and to what is called the aorta. When the windpipe is inflated, it passes the breath on into the hollow parts of the lung. These hollow parts have cartilaginous branchings that converge to a point; and from these branchings there are passages running throughout the whole lung, always passing on from larger to smaller. The heart, too, is joined to the windpipe by fatty, cartilaginous, and fibrous bonds; and where it is joined, it is hollow. When the windpipe is inflated, in some animals this does not become evident, but in the larger animals it is clear that the breath enters into the heart itself. This, then, is how the windpipe is: it receives only breath and lets it go, and nothing else, neither dry nor moist, or it causes pain until what has come down is coughed back up. The gullet is suspended above from the mouth, adjoining the windpipe, continuous with both the spine and the windpipe by membrane-like bonds, and it ends, passing through the diaphragm, into the stomach; it is fleshy in nature, and has extension both in length and in breadth. The human stomach is similar to that of a dog;
37| for it is not much larger than the intestine, but resembles, as it were, an intestine of wide bore; then comes a simple coiled intestine, then a fairly broad intestine. The lower belly is similar to that of a pig; for it is broad, and the part from it to the anus is thick and short. The omentum is attached from the middle of the belly, and is by nature a fatty membrane, as it is also in the other single-bellied and double-toothed animals. Above the intestines is the mesentery; this is membrane-like and broad, and becomes fatty. It is suspended from the great vein and the aorta, and through it run many close-set veins, stretching down toward the arrangement of the intestines, beginning above and reaching all the way down. This, then, is how things stand concerning the gullet and the windpipe, and concerning the belly.
38| The heart has three chambers, and lies higher than the lung, at the point where the windpipe divides; it has a fatty, thick membrane by which it is attached to the great vein and to the aorta. It lies upon the aorta at its pointed end. This pointed end lies toward the chest in the same way in all animals that have a chest. In all animals alike, both those that have this part and those that do not, the heart has its point turned toward the front; though this could often escape notice because it shifts when animals are dissected. Its rounded part is above. The point is fleshy for the most part and dense, and there are sinews within its hollow parts. In position it lies, in the other animals that have a chest, in the middle of the chest, but in human beings more toward the left, inclining a little from the division between the breasts toward the left breast, in the upper part of the chest. It is not large, and its overall shape is not elongated but rather rounded; except that its tip is drawn together to a point. It has three chambers, as has been said: the largest is the one on the right, the smallest the one on the left, and the middle one in size is the one between them;
39| and all of them are perforated into the lung. Both of the small chambers are perforated into the lung. This is evident, in the case of one of the chambers, from below, at the point of attachment. By its largest chamber the heart is attached to the largest vein, to which the mesentery too is attached; by its middle chamber it is attached to the aorta. Passages also lead from the heart into the lung, and they branch in the same way as the windpipe does, running throughout the whole lung alongside the branches from the windpipe. The passages from the heart lie above. There is no passage common to both; rather, because of their junction, they receive breath and pass it on to the heart in turn; for one of the passages leads into the right chamber, the other into the left. Concerning the great vein and the aorta themselves we will speak later, treating both together. Of all the parts in animals, the lung has the most blood, in those animals that have a lung and bear their young alive, whether within themselves or outside; for the whole of it is spongy, and beside each air-passage run branches of the great vein.
40| But those who believe there is empty space in the body are mistaken: they base this on watching animals being cut apart from which the blood has immediately gushed out all at once. Of the other internal organs, only the heart has blood in it. The lung does not have blood in itself but in its vessels, whereas the heart has blood in itself; for it has blood in each of its chambers, and the blood in the middle chamber is the thinnest. Below the lung is the diaphragm of the chest, the so-called phrenes, attached to the ribs, the region under the ribs, and the spine, and having in the middle a thin, membrane-like part. Through it run stretched vessels; and in man these vessels are thick in proportion to the body. Below the diaphragm, on the right side, lies the liver, and on the left the spleen — the same in all animals that have these parts naturally and not as a monstrosity, for the arrangement has in fact been observed reversed in some quadrupeds. The spleen is attached to the lower belly by the caul. In appearance the human spleen is narrow and long, like that of a pig.
41| The liver, for the most part and in most animals, has no gallbladder, though in some it is present. The human liver is round and like that of an ox. This same thing occurs in sacrificial animals too: for example, in a certain place in Chalcis in Euboea sheep have no gallbladder, while in Naxos almost all the quadrupeds have one so large that visiting sacrificers are astonished, supposing the sign to be peculiar to their own animal rather than the ordinary nature of the local ones. The liver is attached to the great vessel but has no connection with the aorta; for a vessel branching off from the great vessel passes through the liver, at the point where the so-called gates of the liver are. The spleen too is attached only to the great vessel, for a vessel stretches from it to the spleen. After these come the kidneys, lying close against the spine itself, similar in nature to those of an ox. In all animals that have kidneys the right one is higher up; and the right kidney has less fat than the left and is drier. This holds alike in all the other animals as well.
42| Passages lead into the kidneys from both the great vessel and the aorta, though not into the hollow part. For the kidneys have a hollow in the middle, larger in some, smaller in others, except in the seal; the seal's kidneys, being like those of an ox, are the most solid of all. The passages that run into the kidneys are used up within the body of the kidney itself; the proof that they do not pass all the way through is that no blood collects or clots inside them. The kidneys have, as has been said, a small cavity. From the hollow of the kidneys two vigorous passages run to the bladder, and others, strong and continuous, run from the aorta. From the middle of each kidney a hollow, sinewy vessel hangs down, stretching along the spine itself through the narrow parts; then it disappears into each hip-joint, and becomes visible again stretching toward the hip. These branchings of the small vessels reach down to the bladder. For the bladder lies last of all, having its attachment by the passages stretched from the kidneys alongside the stalk that leads to the urethra, and it is enclosed almost all the way around by thin, fibrous membranes, somewhat resembling in a way the diaphragm of the chest.