iology of societies in general. The elaboration of these sciences, descriptive anatomy and physiology on the one hand being so extensive, and comparative anatomy and physiology being so precise, would truly be impossible for the sociologist if he had not the assistance of the most valuable auxiliaries. On the one hand the historians properly so called assume the duty of making for him the needed descriptions of societies individually considered. On the other hand the economists, the scholars who busy themselves with comparative law, with the history of religions, of art, of moral ideas, or who criticise political constitutions, all these perform a work of systematization upon the data collected with reference to these different orders of facts. The sociologist then limits himself to drawing from these labors and coordinating the most general results. On the one side, social organisms being studied, he has only to classify them and to distinguish the type of each of the groups which they form, according to the complexity of its structure and of its functions. On the other side, the social facts of each species being known, with their proper laws, the sociologist has only to study the action and reaction of each of these species of facts upon all the others, and to discover the general rules of the evolution of all these phenomena in combination. In a word, his task may thus be restricted to the construction of the general types of societies (or the synthesis of descriptive sociology) and to induction of the higher laws of social forms and functions (the synthesis of comparative sociology). Yet it is evident that, however it may be restricted, the sociologist's task demands enormous labor, and that there is scarcely any present scientific task of which the results might be more fruitful, or of which the accomplishment would be more difficult.
Political economy and sociology being thus defined and placed in contrast with each other, let us now ask what services they may mutually render. And in the first place, what is exactly the contribution of political economy to sociology. We do not hesitate to assert that the construction of the
