96 THE AMERICAN JOURNAL OF SOCIOLOGY
natural selection, have extended over the surface of the earth, adapting themselves successively to special environment, and following directions the general order of which can be approx- imately indicated.
Abstract sociology, however, does not need this hypothesis ; it is sufficient to recognize the constant order which appears in the geographical structure of the globe, and even in its varia- tions; it suffices for it to make clear the fundamental unity and identity of the human species, despite its accessory variations, which, from all points of view, biological, psychical, and social, are limited ; finally it suffices for it to be able to determine what the environments are, especially climatic and alimentary, which correspond to the anatomical, intellectual, and social conditions of primitive man.
We can, then, with reference to this last feature, define the geography of the ensemble in showing that the ancient world extended from east to west over half the globe, but occupied, with respect to latitude, a much narrower space. The northern continents have been more extended and developed ; they are distinguished by a greater continuity of mainland, by a greater variety of contour, by a multiplicity of gulfs and inland seas, islands, and peninsulas. To the south all is massive and nar- rower; the internal and external structure is simpler and less varied. Man has not been able to develop himself there. It is, especially, in the northern continents that humanity has become differentiated, developed, and highly organized.
If the oceans and seas furnish the most natural and general divisions of the different parts of the globe, the most special divisions result from the relief of the soil. Here let us observe, if not a configuration of the ensemble, absolutely uniform, yet, in all cases, general, co-ordinated systems of the greatest impor- tance for social statics, and especially from the point of view of the distribution of natural limits, transitory or not, for the pop- ulation. This solidarity of geographical and orographical systems is the basis for the constant solidarity, past and future, of societies a solidarity affirmed both by their effective rela- tions and by the absence of these relations. This solidarity in
