Among the factors which determine the birth and development of the basic elements of a civilization, one of the most important - perhaps the most important because it represents the synthesis of all the others - is race, that is to say, the ensemble of the physical, moral and intellectual qualities which characterize a people. At the moment when the races of mankind first appeared in history, they has in general already acquired fairly stable qualities which could only be transformed very slowly afterwards. The oldest Egyptian bas-reliefs, upon which are found reproduced the diverse peoples...