Page:American Journal of Sociology Volume 9.djvu/249

 INTRODUCTION TO SOCIOLOGY 235

which are connected with the distribution of the human species. The study of the distribution of the human species, in its turn, is, properly speaking, the basis of the philosophy of social and political frontiers.

The present state of the distribution of animals has its point of departure in the previous geologic and geographic transforma- tions. The distribution of animals corresponds always to these two conditions, as the flora and fauna themselves, at the expense of which certain animals subsist.

As explained by Professor A. Lamcere in his lectures upon transformism, the geographic distribution of organisms is proof of their tranformism. This principle had been clearly estab- lished by Charles Darwin, and also by Wallace {Island Life]. This distribution is, indeed, dependent upon exterior conditions; upon the geological constitution of the soil which causes varia- tion of the flora, and therefore of the fauna : it depends upon climate, natural barriers (deserts, mountain ranges, seas, etc.), and upon the interior state of the planet. Hence the large islands contain the same animals as the neighboring continent, for the reason that the lands were formerly joined together. The geographic distribution of animals testifies also in favor of natural selection, that is to say, the survival of the fittest. For instance, the little islands rising from the ocean include only some types that have been able to transport themselves thither, as birds, bats, insects ; or to be thither transported, as lizards, rats, etc. The insects are for the most part apteral. Those which had through variation lost their wings had, indeed, a greater chance of survival, because not so liable to be swept by the wind into the sea. These interpretations should not be lost sight of when we come to consider the distribution of the varieties of the human species.

Although in some respects the means of locomotion of ani- mals are superior to those of plants, it seems that the animal forms and their habitats have varied very little in fifty centuries among the most ancient historic civilizations, Egypt, Babylon, Persia, India, China, and Greece, if one may judge from the remnants and documents of these antique civilizations. This