The number of hairs is very variable on the same surface. In some people they are very close together and even all touch; in others more thinly scattered, they allow in part the skin of the cranium to be seen in their interstices, a circumstance which is either owing to original conformation, or to a disease which makes them fall out in part. They have, like the nails, a determinate growth which they do not exceed. We know but little of the limit of this growth. Yet we have seen them reach to the waist, the thighs, and the legs even. It appears that in women they have a greater growth; we might say, that nature has compensated this sex in this way for the want of hair in many other parts. Floating upon the shoulders, the breast, the trunk, &c. they form in the natural state a sort of protection from the injuries of the air and the light. Their extent evidently proves that man was destined to an erect attitude. In fact, in the attitude of quadrupeds, they would trail much upon the earth, and form an obstacle to motion. The hair of no animal, I believe, in a natural attitude retards his progress so much, as the hair of man then would.
Man, who opposes nature in every thing, has made it a habit in most societies to cut the hair, the beard, &c. By common people, it is considered merely a thing of fashion; by the physician, as a practice which has perhaps a greater influence than is thought upon the functions. In fact, in the natural state when the pilous system has once acquired its growth, it no longer exhibits the constant motion of composition and decomposition. On the contrary, in man who cuts it, it is constantly the seat of this motion and of that of growth. This practice perpetuates then the phenomena which take place in them in infancy, and consequently keeps up there a more active work, which perhaps is performed at the expense of that of many other parts.
The natural difference of the hair has much influence upon its length; that which is smooth and curls but little is in general the longest. The more it has the opposite characters, the shorter it is, as is proved by that of negroes and those white people whose hair curls like theirs.
The tenuity of the hair is very great, yet its resistance is in proportion very considerable. There is no part in the economy, not even those of the fibrous system, which can support so great a weight in proportion to its size. Thus woven strings of hair would have an enormous resistance, if they were sufficiently long to be employed for different uses.
The colour of the hair varies remarkably according to country, latitude, climate, temperature, &c. This colour is even, like that of the skin, a characteristic attribute of the different human races. Naturalists have been much occupied with this subject, and I refer to their works.
In our climate the principal colours are black, flaxen and bright red. They are, as it were, the three general types to which may be referred many particular shades. The black has under it the brown, the chesnut, &c. The flaxen is connected on the one hand with the bright red and on the other with the chesnut. The bright red which touches the flaxen by one of its extreme shades, goes by an opposite shade to the natural colour of certain flames.
All physicians have considered the colour of the hair as among the characters of the temperaments. Black indicates strength and vigour. The figure of a wrestler with flaxen hair would be almost ridiculous. This colour is the attribute of weakness and delicacy; it floats upon the head of figures which painters have made strangers to the great passions, to powerful and heroic deeds; it is found upon the figures of young people, in pictures where laughter, sport, grace and pleasure preside over the subjects. These two colours, black and flaxen, as well as their secondary shades, are found distributed among women in nearly equal proportion; now reflect upon the kind of sentiment this sex inspires according to the colour of the hair, without regard to any other consideration, and you will see that a woman with flaxen hair creates a sentiment which beauty and weakness united seem to dictate. The epithets that we employ express this double attribute. On the contrary, the term brunette announces in her that it designates, a mixture of force and beauty. Beauty is then a common gift which attracts us, but which, differently modified by external forms, attracts us by touching, interesting and exciting us. Eyes in which langour is depicted, are frequently associated with flaxen hair; whilst black hair is almost always met with, in those whose vivacity and sparkling seem to proclaim an excess of life which seeks to be diffused.
Habit which accustoms us to every thing, changes our taste in regard to the colour of the hair, as it does to that of our dress. Black, flaxen and their numerous shades are in turns fashionable in France; and as the organization does not change with our taste, we have contrived artificial hair; a happy means, which seems to subject to our inconstancy the invariable course of nature, and which, changing at our will the expression which the physiognomy borrows from the hair, can at every instant exhibit man under forms which fashion extols to day, and which ridicule pursues tomorrow. Now among these numberless variations which succeed each other among us in the fashion of the hair, bright red and its various shades never find a place. Most people have a decided aversion to it. It is almost, in our eyes, a mal-formation to be born with it. This opinion is too general not to have some real foundation. The principle appears to me to be the usual connexion between the hair and the temperament and of course the character which results from this; now the kind of character connected with this kind of hair is not commonly the happiest, though there are many exceptions to this principle, which is proverbial. Another reason for the aversion to hair of a bright red, is that the oily fluid which lubricates it often exhales a fetid odour foreign to the other kinds of hair.
What is the relation that can exist between the hair and the character? Has the first an influence upon the second? No; the following is the way in which it should be considered. Every man has his peculiar kind of organization and constitution. This forms the temperament; now, to each kind is attached on the one hand this or that species of hair, and on the other the predominance of some internal viscera, which though less apparent is not less real. This predominance disposes evidently to certain passions, which are the principal attributes of character; then the colour of the hair and character are two different results from the same cause, viz. constitution; but one has no influence upon the other.
The hair coming out of the cutaneous pores has such a direction, that that of the anterior part of the cranium is almost always oblique in front, and tends to fall over the forehead; that of the middle and posterior part pierces the skin perpendicularly, and that of the posterior and inferior part traverses it obliquely, so as to fall naturally down the length of the posterior part of the neck. It is the same with that of the sides, which its direction as well as its weight, carries upon the region of the ear which it covers.