Naturalists, travellers, and anatomists announced long ago that the brain of the Negro is distinguished from that of the White by its blackish colour. An experiment performed at Paris under the superintendence of M. Rayer, upon which I have already made some passing remarks, confirms the general fact. I have already observed how M. Gubler, by whom it was prepared, wished to discover if there were no mean terms. He examined the colouring of brains obtained from individuals, all belonging to the White race, but whose complexions were differently coloured, and proved that the internal colouring was in direct relation with the external. In fair individuals with blue eyes and a pink and white skin, the pigment seemed to be entirely wanting. In individuals with a brown skin, black hair, and a very dark iris, “not only the brain enveloped by its membranes assumes a deeper shade, but a layer of black matter, in every way comparable to that of the Negro, covers the protuberance, the pineal gland, and some other points of the nervous centres.”
Thus, internally, as well as externally, the colouring of tissues presents that graduated series to which I have so often called attention. This removes, therefore, the absolute nature which had been attributed to a peculiarity which had so often been insisted upon as separating the Negro from the White, to the extent of making him a distinct species.
VIII. Vascular and respiratory systems. Considered as a whole, the vascular system of the Black and that of the White present facts somewhat similar to those which we have observed in the nervous system. According to Pruner Bey, the venous system predominates visibly over the arterial in the Black; and here, again, the admirable preparations of Jacquard are a material proof of the correctness of the observations of the savant I have just quoted. This predominance seems to extend to the right cavities of the heart.
The lungs are less developed in the Negro than in the White. M. Pruner Bey has observed cases in which they seem to be pressed upwards by the abdominal viscera. The characters peculiar to the blood of the Negro, which were noticed in a preceding chapter, will, perhaps, at some future time, be connected with this group of anatomical conditions.
We have already seen that the cutaneous glandular system is more developed in the Negro than in the White. The investigations of M. Pruner Bey demonstrate that the same fact reappears throughout the whole length of the intestinal canal, the surface of which is everywhere marked by the prominence of secreting organs, especially in the stomach and colon. The large glands which are connected with the alimentary canal are also remarkably developed, particularly the liver. The case is also the same with the supra-renal capsules. All these organs are in a constant state of venous hyperemia. Finally, these intestinal mucous membranes are very thick, and present the appearance of adipose tissue. Facts of a similar nature will perhaps be observed in the greater number of intertropical races. We already know that in the Javanese the liver is as fully developed as in the Negro.
CHAPTER XXXI.
PHYSIOLOGICAL CHARACTERS.
I. The special history of human races presents a considerable number of interesting physiological facts which are sufficiently different and well marked, to serve as distinctive characters. We find in the tropics peoples remarkably abstemious, and living entirely upon vegetables, without their organism being injuriously affected; in the polar regions there are others who eat fat in quantities which would be rejected by our digestive organs; there are also some slight variations between the respiration, circulation, animal temperature, secretions, etc. of the White man and the Negro; the muscular energy and the manner in which it is employed, sometimes vary considerably in different races; general sensibility, and consequently aptitude for feeling pain, are very unequally developed. The same surgical operation will not cause as much pain to a Chinese as to a European.
But the greater number of these traits arise from peculiarities which do not belong to general considerations. Many are the result of anterior facts, and are connected with conditions of life, habit, etc., sometimes even with beliefs and institutions. Even if we confined ourselves to a mere sketch, we should have to enter into details incompatible with the plan of this book, if we wished to discuss all these questions. I shall, therefore, here confine myself to pointing out some general phenomena to justify the above statements.
II. I will, in the first place, say a few words upon certain facts and ideas which have often been the occasion of animated discussion. I mean the degree of relation admissible between the development of the intelligence and that of the brain. This question may seem at first sight to belong almost entirely to the study of the individual. But, from the manner in which it has been applied to the appreciation of the intellectual power of races, it has acquired a real interest in general anthropology.