600 THE AMERICAN JOURNAL OF SOCIOLOGY
on the earth. But whatever its length, that period is long past, and the period of social integration has been at least as long. All the cases of simple assimilation had run their course ages before there were any records of any kind, and human history acquaints us only with types of a far higher order.
In other words, the only cases of which we have any actual knowledge are cases of compound social assimilation. Compound assimilation results when peoples or nations that have already been formed in the manner described out of lower social elements again amalgamate on a higher plane and repeat the process. When one perfectly integrated nation conquers and subjugates another, the same steps have to be taken as in the case of simple groups. The struggle is as much more intense as it is higher in the scale of social structure. But the new structures developed through it, although they have the same names and the same general character, become, when formed, more powerful and capable of accomplishing much more. The new society is of a higher grade and a more potent factor in the world. The new state, the new people, the new nation, are on a higher plane, and a long step is taken toward civilization.
But all the nations of which history tells us anything have undergone much more still than two social assimilations. Most of them have undergone many, and represent highly complex structures. With every fresh assimilation they rise in the scale of civilization. What they acquire is greater and greater social efficiency, and the principal differences between races, peoples, and nations are differences in the degree of social efficiency. Not only are the same social structures acquired in the first assimilation greatly increased and strengthened, but a large number of other, more or less derivative, but highly socializing, structures are added. The system of law, which was at first only a sort of police regulation, becomes a great system of jurisprudence. Gov- ernment, which at first had but one branch, viz., the executive, acquires a judicial and finally a legislative branch. The state becomes a vast systematized organization. Industry, which at the beginning consisted wholly of slave labor under a master, and later included the simplest forms of trade, develops into a system