Part 39

Upon the arch which borders the orbit above, is found a collection of hairs forming a portion of a circle more or less evident, which shades the eye and defends it from the too powerful impression of the rays of light. The hairs of the eyebrows are thicker together in persons of dark complexion, than in those of light. More numerous within, they sometimes unite together the two eyebrows upon the nasal prominence, and thus shade the root of the nose. Fewer without, they there cause the eyebrow to terminate in a point. All are obliquely directed from within outwards. Sometimes towards the internal side, they go perpendicularly forwards. Their length is scarcely more than half an inch; they do not exceed this except in some extraordinary cases. Their colour is usually, though not invariably, the same as that of the hair. They are firmer, more resisting and larger than the hairs of the head. If they were longer they would curl like the hairs on the genital parts, of the nature of which they partake.

The eyebrows enjoy two evident motions. 1st. They are depressed and carried inwards, by forming over the eye a very evident arch. 2d. They are raised up and separated from each other, by expanding the parts around the orbit. The length between the extremes of these two motions is nearly an inch. The first motion takes place to defend the eye from a very bright light. It expresses also the melancholy and gloomy passions; hence the reason no doubt why the same word is applied to the moral state of the mind, and to the row of hairs of which we are treating. Observe on this subject that the sanguineous and choleric temperaments, which are the most disposed to the passions which make the eyebrows contract, are precisely those in which the hairs that compose them are found in general the most evident. The second motion enables us to receive upon the region of the orbit a great quantity of the rays of light; it allows us to raise the upper eyelid to a great extent in order to open the eye wide, which the first evidently prevents. It expresses also the gay passions, those which dilate the face. Painters have studied more than anatomists, the different degrees of elevation and depression of the eyebrows.

Eyelashes.

Upon both eyelids there exists a small row of hairs, a little longer than those of the eyebrows, of the same nature as them, directed obliquely forwards, crossing each other when the two eyelids are brought together, and serving to defend the eye from the small particles floating in the air. In general they do not curl; when they do and turn towards the eye, an irritation ensues, and they must be cut off. Sometimes a bad direction is the cause of this irritation.

I would remark on the subject of the eyelashes, that all the openings of communication with the interior, as those of the meatus auditorius externus, the nose and the anus, and oftentimes also the orifices of the lactiferous tubes, are surrounded with a great number of hairs which defend these openings from external bodies. Around the mouth the beard takes the place of these hairs; the urethra has none, but the prepuce at its orifice is instead of them.

Beard.

The males of most animals are distinguished from the females by some external productions. The comb of the cock, the mane of the lion, the horns of the stag, &c. are examples of these distinctive characters. In man, the beard is the principal attribute of the male. It occupies all the chin, the sides of the face, both lips and the superior part of the neck. It leaves the cheeks bare as well as the parts around the eyes; thus observe that it is there that the passions are principally depicted, the expression of which would be concealed by the hairs, if the lower part of the face was the seat of them.

The beard, not so long in general as the hair of the head, is longer than that of every other part of the body. It is very commonly of the colour of the first, though more rarely flaxen and is more frequently of a bright red, which it often is in persons with flaxen hair. The nature of the hairs of the beard is the same as that of the hairs of the genital parts, the eyebrows, &c. They curl, are stiffer, more resisting and uniformly less oily than the hair of the head.

The quantity of beard varies remarkably in different men. Those in whom it is abundant and of a deep black are in general strong and vigorous. Observe also that the strongest males in the different species of animals are those, in whom the external production which distinguishes them from the females, is the most conspicuous. We might say that this characteristic production is the index of the strength or weakness of their constitution. A small lion has not a noble mane; great horns belong to a well made stag, and long, twisted ones to a good formed ram. Observe that it is not the same with the other hairs common to the two sexes. Often in a weak man, those of the arms, the thighs, &c. are as evident and even more numerous, than in the most muscular.

The habit of cutting the beard as most Europeans do, of preserving it like the Asiatics and of dressing it in different ways like the Chinese, gives a different expression to the face which characterizes the people. A masculine, vigorous physiogomy which expresses strength and energy, cannot be deprived of this external attribute without losing a part of its character. That of the Orientals exhibits an appearance which coincides with the strength of their bodies, and forms a contrast with the effeminacy of their manners. I do not know if, in consulting the history of the different people who allow their beard to grow, and that of nations who cut it, we might not be tempted to believe that muscular force is to a certain extent connected with its existence, and that this force is always diminished a little when we are constantly deprived of it. Every one knows the vigour of the ancients, that of the people with long beards, and that even of certain men who, among us, allow their beards to grow in conformity with the laws of monkish institutions. No doubt many causes may make weakness exist with a beard; but in a general view I think we can admit that there is a certain relation between it and strength. Take from a cock his comb, which is the characteristic of the male, as the beard is that of man, and he will lose strength. I am persuaded that we might take from the lion a part of his power by taking away his mane. We know the result of the experiments of Russel upon the castration of stags; their horns, after this operation have grown in an irregular manner, or have not even grown at all. This external attribute of the male in this species, appears as we know at the period of virility, when the vital forces are increased. It is the same with the human beard. This coincidence would alone prove that the use of this last is to serve for an external character to the male sex. The eunuch, whose powers are feeble, loses also oftentimes much of his beard.

Such are our prejudices in regard to the idea we form of beauty, that we ridicule what is really and absolutely so, for that is certainly so which indicates organic perfection. A peacock without his tail of emeralds, a ram or a stag without their horns, displease us; why does not man without his beard?

II. Of the Pilous System of the Trunk.

The hairs on the trunk are very variable. Some men appear as it were shaggy, whilst others are almost without hairs. There are more of them generally on the anterior than on the posterior part of the trunk. It is principally along the linea alba and upon the chest, that they are found in man. This last part is in general destitute of them in woman, who has usually very few on the trunk.

Both sexes have a very considerable quantity on the genital parts. They are there, as I have said, of the nature of the beard. Less frequently flaxen than the hair of the head, as frequently of a bright red, they are most usually black. They are, next to the beard, the longest hairs. They have generally no determinate direction; each hair almost has a different one. Few animals, like man, exhibit this excess of hair upon the genital parts. There is a great difference in individuals as to its quantity. The blackness and abundance coincide in general with strength.

III. Pilous System of the Extremities.

Man has many hairs upon the whole surface of his extremities. The proportion of number is nearly the same in all; but the length varies very much; in some, they form only a down; in others, they are a little longer; whilst in others, they are nearly of an inch in length, reach over each other, and give the extremities a shaggy appearance.

At the top of the superior extremities, there is in the hollow of the axilla a collection of hairs which are longer than the others, and are nearly of the nature of those of the genital parts. Nothing similar is seen on the inferior extremities.

The pilous system does not exist on the internal part of the arm and fore-arm in many men, in whom we see it only behind and on the sides. It is more uniform on the inferior extremities. The back of the foot and hand always have hairs. They are never seen on the sole of the one or the palm of the other; a circumstance of essential advantage to the perfection of touch.

ARTICLE SECOND.

ORGANIZATION OF THE PILOUS SYSTEM.

Whatever varieties exist in the form, size and arrangement of the hairs, their organization is nearly the same in all. We shall now examine this organization in a general manner. Chirac, Malpighi and all anatomists since them, have explained very well in some respects, and very badly in others, the structure of the hairs of the head, which is nearly the same as that of all the other hairs. The following is what careful dissection has shown me concerning it.

I. Origin of the Hairs.

The hairs of the head, and in general all the hairs, arise from a sub-cutaneous fat, or the cellular texture of the parts which are destitute of this fluid. Each is contained at its origin, in a kind of small membranous canal, the nature of which is perfectly unknown to me, and whose transparent parietes allow the hair to be plainly seen, when we have separated them with a delicate scalpel from the surrounding parts. This small cylindrical canal accompanies the hair to the corresponding pore of the skin, insinuates itself into this pore, passes through it, extends to the epidermis and is intermixed there with the texture of this membrane, but goes no further. The length of this canal, and consequently of the course which the hair runs under and in the skin, is nearly five lines in the hairs of the head. There is no adhesion between the hair and the internal surface of this small canal, except at the enlarged base of the first where, it receives its nourishment. Thus, by opening the canal at this place, and destroying its adhesions there, the hair becomes free, and is drawn from without inwards with great ease, by taking hold of its enlarged end with small forceps. In this way, the canal is insulated. I have thus dissected and separated, upon a surface of two inches, a very great number of these canals which appear, when nothing but them is left on the internal surface of the skin, like so many small elongations of it.

Are there vessels and nerves in this small cylindrical sac which contains the origin of the hairs? We see distinctly elongations going to its external surface, especially towards its extremity opposite to the skin; but dissection does not teach us the nature of these elongations. I have never been able to trace them to a neighbouring vessel or nerve. Haller has not been more successful, though he speaks of authors who have traced nerves to the origin of the hairs. I presume however that these elongations are especially vascular. Is there a fluid between the origin of the hair and its covering? By opening the latter, nothing escapes, though some authors have pretended the contrary. Besides, if this fluid is in the form of dew, as upon the serous surfaces, it cannot be distinguished.

It is in the middle of this small cylindrical sac, of which I have just spoken, that the origin of the hair is found. We see at its extremity an enlargement oftentimes almost insensible, at others very evident, though always less than has been said. This enlargement is of the same colour and nature as the hair itself. It adheres to the canal very probably by the vessels and perhaps the nerves it receives from it. The hair which arises from it goes through its canal without adhering, as I have said, to its parietes, passes with it through the oblique pore of the dermis, leaves it at the epidermis, and goes outward.

All authors say that the hair does not pierce the epidermis, but only raises it up, and that this forms a sheath which accompanies it to its extremity. This assertion is incorrect; in fact, 1st, the hair is as thick in its canal of origin as it is out of it. 2d. This canal being opened at its extremity opposite to the skin, we can draw out of it, as I have said, the whole hair with great ease, and without the least resistance; which would not be the case however if the covering of the epidermis was to be broken. It appears that from the enlargement of its extremity, the hair has no adhesion either in the sub-cutaneous canal, or in its passage through the skin, or the epidermis. 3d. If the cutaneous epidermis was raised up to cover the hair, this would have a treble thickness, unless this epidermis became wonderfully thin upon it. 4th. We do not see this pretended rising up by drawing out a hair of the head; on the contrary a depression exists at the place where this comes out. The cutaneous epidermis furnishes nothing then to the hairs, though the nature of them may be in part the same as its own, and it is proper to consider them as uniform in their structure from one extremity to the other.

Under the skin, through it and out of it, the hair is composed of two distinct parts. One external, forms a canal which extends from the enlargement of the dermoid extremity to the opposite one; the other internal, which composes as it were the medulla of it, is of an unknown nature.

II. External Covering of the Hairs.