Aristotle's Problems

Why does the beard grow red without the head [doing so], while the head does not grow red without the beard? Surely because red hairs arise from weakness, and the hairs in the beard are by nature weaker. This may be observed from the fact that men become beardless, but they do not go bald [there]; or I maintain this. It is certain, therefore, that the place [of the head] can scarcely bear them; wherefore, since he who is stronger bears yellow hairs, it is necessary that the weaker one also bear them; but if the latter [bears them], it is not however necessary that the stronger one should.

Why does long hair fall out? Surely because the hair is indeed a saw; and beneath the saw is the skin; yet those things which are far distant beneath the saw easily fall away when moved, and generally those things which are far from the stationary part; these things can easily be seen in mechanics.

Why are gray hairs not produced in the eyelashes? Is it on account of the property of the nutriment about the eyes? For from this it may be conjectured that fatty flesh is produced there; and by nutriment of this kind, hair is rightly not much increased, since what is produced from such redundancies does not grow gray. For turning gray happens through a certain corruption and a defect of nutriment.

Why do the nails on the hands grow more quickly than on the feet? Is it because growth climbs more upward, wherefore hairs also grow sooner on the chin than on the pubes? Or because the hands receive increase in heat, while the feet receive it in cold? Or rather that all [upper] parts are hot? Or because the hands are hotter and more moist, while the feet are the coldest of all the limbs of the whole body? And parts of this kind, such as hairs and nails, for this very reason, being both cold and situated in a cold place, receive increase with difficulty, whereas those on the hands do so on the contrary.

Why is curly hair produced? Surely because they are driven by two directions of growth, the growth being held inward by the surrounding heat; for which reason the Ethiopians are such.

Why do places burned by fire not produce hair? Is it because the skin becomes dense? And it must be porous where hair grows to maturity.

Why do thick hairs not become long? Either because the growth, not being drawn out into length, is consumed in thickness; or because thick hairs are hard, and a hard thing is moved with difficulty whereby the hardness may increase; since it comes from the earthy [element], and earthy nutriment does not tend to be sent upward. Therefore, the slowness of motion anticipates the increasing heat so that they hinder each other; accordingly, it grows out into thickness and width, not in length.

Why are thick hairs denser than thin ones? Is it because they appear so on account of their thickness? For whatever lies between equal things is less apparent. Or because they immediately grow out into length? Thus in many ways the nutriment arises, being retained within, and not immediately leading out by an impulse that thrusts upward.

Why are hairs thinner in bony places? Surely because the skin is not thick; and from thick skin thicker hairs are born.

Why do reddish hairs become blacker when scorched? Surely because whatever was moist is cooked more in a small amount by the heat that underlies it. For yellow [hair] comes from defective nutriment, but black from healthy nutriment.

Why do the Ethiopians have curly hair, but the Scythians and those who dwell toward the North have long and flowing hair? Surely because hair dried by the sun is bent back and curved like other things; and the Ethiopians are affected by the sun and by an excess of heat. But the Scythians are in a cold place where the sun, by scorching, in no way compels the moisture in the hairs to evaporate; hence it is that they are not curled. And if they must be either bent back or long, since they were not curled, they will be long and straight.

Why, in the weak and the aged, when the rest of the body is thinned, do the nails and hairs yet grow? Because of the nutriment, one part goes into flesh, another into bile, and another into the distribution of all the thin parts. Whichever bodies, therefore, are hot and robust, can convert food into bile and blood. But weak ones can do so least of all, but rather into those things which are worthy of the least nutriment, such as nails and hairs. For instance, they say the Illyrians, slain in battle and dead, have heads sprouting with hair within a few days; and likewise, as the bodies are consumed, the nutriments slip away and are distributed into these redundancies.

Why do the hairs on the feet turn gray either not at all, or late, or only in those finished by age? Is it because they turn gray sooner in the face, or on the head, or on the thigh? And the upper place is most opposite to the lower, and in contraries, it rightly happens that contraries occur. Or because grayness seems to be a sign of old age, and old age is a certain corruption and defect of heat. But as to why they become gray, that is of another reasoning. Furthermore, the kind of cause of this defect happens to those affected by old age because heat departs, wherefore also wrinkles come upon the face and blood ceases to flow from the nostrils, the calves are dried out, and hemorrhoids are born. But if grayness is a defect of moist heat, and this force descends to the feet, just as also to the pubes, these places rightly grow gray later than the upper ones, and that more so in the feet; but when everywhere the moist heat has dried up by the multitude of years, then at last, even in the feet white hairs are produced.

Why does wool sprinkled with oil become whiter, but hairs when anointed become blacker? For wool too is hair.