Page:Popular Science Monthly Volume 2.djvu/566

546 a race if left to multiply. Here, again, in the case of animals, the difference from race to race is much greater than in the case of man.

Sometimes, in the presence of variations of color like these we have described, we ask if, between the negro and the white, there do not exist anatomical differences in the skin? The minute study of this organ answers us in the negative.

The skin is composed of three layers, which together constitute a true organ having its proper functions. So it is often called the cutaneous organ. On the exterior is the epidermis, that dry and insensible layer which covers the entire body, and protects it against the action of outer agents.

Interiorly, and immediately above the greasy body, is the true skin—it is the essential and living part of the cutaneous organ; it is this which receives the blood-vessels and nerves.

Between the true skin and the epidermis is a dark layer, composed of distinct cells. It is the mucous membrane of Malpighi, so named from the anatomist who first described it. The cells that form it are a simple secretion of the true skin. It is this layer which is the seat of color. It exists in all men, but the cells that it contains are more or less colored according to race. In whites themselves, in certain parts of the body, around the nipples, in the specks of freckles, in the beauty-spots, etc., we sometimes see them as deep as in the negro.

You see that the color in different human races is, when developed, only a phenomenon of local coloration, of exactly the same nature as those we encounter in races of domestic animals. If time permitted me to enter more fully into the subject, I could make this fact much more evident, but the hour advances and I must hasten.

To the skin are attached a certain number of organs, which may be considered as adjuncts to the cutaneous organ. These are chiefly the villosities or hairs, the sebaceous glands, and the sweat-glands. Between these annexed organs there exists a certain balance which physiology easily explains. So in glabrous races, that is, races with little or no villosities on the body, the sebaceous apparatus is much more developed. This fact is very marked in the African negro, whose skin sometimes bears slight prominences, sketching a sort of arabesque by the extraordinary development of these little organs.

It is to the development of the sebaceous apparatus that the odor developed by the negro is due. This odor is so strong, so persistent, that it suffices to the identification of a negroship a long time after it has left the trade. But it is not negroes alone that are characterized by malodorous exhalations. It is the same with the whites themselves. You all know that a dog follows his master by the scent. Savage people, whose senses are more exercised than ours, distinguish very quickly the general odor which characterizes a race; and, in Peru, they give special names to that of the white and of the black as well as to their own.