The natural history of the human species : its typical forms, primeval distribution, filiations, and migrations / by Chas. Hamilton Smith ; with a preliminary abstract of the views of Blumenbach, Prichard, Bachman, Agassiz, and other authors of repute on the subject, by S. Kneeland, Jr.

  • Smith, Charles Hamilton.
Date:
1851
Catalogue details

Licence: Public Domain Mark

Credit: The natural history of the human species : its typical forms, primeval distribution, filiations, and migrations / by Chas. Hamilton Smith ; with a preliminary abstract of the views of Blumenbach, Prichard, Bachman, Agassiz, and other authors of repute on the subject, by S. Kneeland, Jr. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    30/449
    Microscopical investigation has shown that the skin does not consist of continuous membranes, but is composed of several layers of cells not separated from each other by such definite lines. Henle has found that the apparently membranous parts, which give color to various surfaces, are also of a cellular structure, and not properly mem- branous ; in the skin of the Negro he found numerous irregularly spherical cells containing the black pigment to which the color is due ; they were most numerous on those parts of the rete which pro- ject and correspond to the furrows of the cutis. Dr. Simon, of Berlin, has found that the various discolorations of the white skin depend on the presence of similar cells filled with pigment, and that they are related on the one hand to the normal coloration of the Negro skin, and on the other to the disease termed melanosis, in which the production of pigment cells keeps pace with a change from the normal or healthy state of organization in the affected parts. He thence concludes that there is no organic difference between the skin of the Negro and the European, which marks them as dis- tinct species. It may also be added that the epidermic tissue, to which the horny tissue of many animals corresponds, and which is the seat of the variations in color and in the hair of man, is precisely that part of the organic system which undergoes the most striking and even surprising alterations. The complexions of mankind are not permanent characters ; there are many changes from white to black, and vice versa, and both complexions are seen in the undoubted prog- eny of the same stock ; so that no argument, according to Prich- ard, can be drawn from color against the original unity of the human species. The human races have also been distinguished by the color, quality, and quantity of the hair; these national diversities probably do not exceed the measure of variety occurring in different families of the same nation. Some Europeans are said to have hair quite as crisp and curly as that of a Negro ; even among Negroes, we find every variety from a so-called woolly hair to curled or even flowing hair; the same is affirmed of the natives of the Southern Ocean, where there is no intermixture of races. The nature of the Negro hair has been the subject of much discussion, as it was supposed to possess characters indicating a distinct species. The Negro hair is called wool, meaning that it approaches the wool of animals. The fibre of true wool is rough on its surface, and has a feathered or barbed edge ; this is at the same time the cause of its felting prop- erty, and the mark which distinguishes it from hair. Examined microscopically, the fibre of wool generally has serrated edges, resulting from a structure resembling a series of inverted cones,