240 THE AMERICAN JOURNAL OF SOCIOLOGY
by the genetic relations of the members of each group, and by the natural environment in which the latter was placed. The sea, as a temporary natural limit and an instrument of circulation and communication, facilitates the internal organization of societies that are poorly equipped for protecting their existence against the outer world. On this account, societies even relatively consider- able have been naturally able to fix and consolidate themselves in the Polynesian islands, in Haiti, Havana, Tonga, and Samoa. In ancient Peru, before the domination of the Incas, semi-civilized societies had already similarly established themselves along the coast in regions separated from each other by almost impassable torrid deserts. The situation was the same in the interior of the countries, in regions separated by elevated mountains or by the cold and uninhabitable punas (table-lands). These natural limits (natural, for the moment) were at once obstacles to the absorption of social groups and a favorable factor for the conservation of the communal and equality forms, thus sheltered from external attack, and in consequence momentarily free from the necessity of a military and authoritative organization a necessity which is originally imposed upon groups whose territories are easy of access. But, in reality, there are no natural frontiers. There are only social frontiers, that is, frontiers in correspondence with the external and internal conditions of each group. As the internal development of the populations of Peru, prior to the conquest, had naturally brought them to exceed their natural frontiers, so these frontiers were crossed by the conquering tribes of the Incas, who were precisely found in the state of emerging from their own frontiers. They survived all of the originally independent tribes and imprinted upon the new unified organization of tribes a character which, while maintaining the old communal type, developed and stamped upon it the inequality character resulting from conquest. And this inequality character was not alone political. It had a strong economic basis. It was no longer an autonomous group regulating its economic life over its own territory. The laws of the community passed into the hands of the Incas. All of the old so-called natural divisions between tribes were replaced by divisions in harmony with the new social organi-
