In Blumenbach’s opinion, all races are unhealthy deviations from a primitive type, of which we are the representatives;[230] so that nine-tenths of the human kind are, according to him, composed of degenerate individuals. Blumenbach did not know that one of the essential characters of degeneracy is the limited development of its produce, that is to say, the disappearance of the race at a more or less distant period.[231] We ask ourselves only how monogenists, who all partake more or less of Blumenbach’s opinions, and who nearly all pride themselves on moral and humanitarian sentiments, can consent to lower in this manner the number of human beings who are worthy of this name? Is not the best part, if there could be one in the case of science, played by the polygenists, who consider that other races are special entities, pursuing an end, which is their own and not ours, and dividing with us the planet, inaccessible in all its extent to the Iranian; just as certain kinds of animals, likewise, cover the globe with different species? Climate, we have said, has a decisive influence upon a man taken to another country; it must only be understood in the sense of this influence, and we have seen that it is generally a pernicious one.[232] It makes itself felt in the physical and moral nature of man, both deeply and superficially. We may point out among the most simple and the most profound climateric influences, the _sun-burn_, the study of which is so interesting in anthropological study. We know, at the present day, that the sun is far from being always the cause of it; that a bivouac _at night_ has as powerful an action in the same manner, and that the north-pole explorers found that their hands and faces were browned under a northern sky.[233] Are these not facts which will diminish the decisive part which has so long been given to solar heat in the production of colouring matter in the Negro?[234] The colour of sun-burn does not even seem to remain in the layers of the epidermis, in which the normal colour is found. Indeed, we must remember, that it is always easy to distinguish a sun-burnt nation, since individuals who, for some reason or other, are but seldom exposed to external influences, like the women, are infinitely whiter; children are quite white when born, but as soon as they go much into the air, they become brown.