In our own opinion, history is very far from commencing with mankind; it only goes back two or three ages before the invention of figurative language,--a more important and difficult language for man than articulated language, which was discovered long before, and at many different points. It is _writing_ which makes the Asiatics and the lost people of Central America better than savages; and if we were asked for a specific distinction with regard to intelligence between mankind and animals, we should only be able to find it there. It will be seen later that we are far from denying the influence of a middle course; but we maintain that every term of comparison is wanting at the present day to show that man, since the most distant historic periods, has ever shown less dissimilarities than now. Most monogenists, disagreeing about the whole system of modifying causes, agree generally in acknowledging that climates and hybridity have a decisive creative influence as regards races of men. These two kinds of influence alone deserve our consideration. We shall commence by climate, putting on one side, for the present, the study of the specious question of hybridity, whose part is so badly understood by those who believe that it creates varieties, when it can only weaken differences. An important part in the means of alteration from one race to another has been given, by Hippocrates, to external influences. He seems to have been the first to point this out, in his _Treatise on Air, Water, and Places_.[207] “The form, colour, and manners of nations,” says Polybius, “depend solely on the diversity of climates.”[208] In general, the ancients believed in the immediate and sudden influence of climate, so much so that a stranger, at the end of a few years, would be completely changed and altered to the type of the inhabitants of the same place. In our days, Cabanis alone has dared to go so far as this.[209]