INTRODUCTION TO SOCIOLOGY 783
arms, by natural and artificial barriers, by protection and by free competition, having to protect themselves by the excellence of their external and international organization.
Before studying the philosophy of the social boundaries of the future, and even that of the limitations of modern states, which are very complex structures, it is necessary to take up the philosophy of the natural limitation and equilibration of things and organisms in general ; then those of primitive socie- ties, peaceful and warlike. Finally it is necessary to investigate this same constant limitation in ;the economic field and in all the social functions and organs, including the juridical and politi- cal. Here again, as in my former observations, we shall see more and more the social contractual forms, including equally the political contractual forms, separating themselves from the more ancient and crude forms, and limiting the reciprocal rela- tions of the social units and aggregates as well as the societies between them, from the most simple industrial association up to that large universal society of which the relations, intertwined more and more among the various parts, formerly separated by insuperable boundaries, prepare the way for a natural formation.
This constant equilibration which results between the inter- nal structure in relation to the environment seems, in a way, most admirable in the statics of the organisms most developed of all, that is, those constituting the human species, and espe- cially in the psychical organization of the latter. The limits of organic variations become more extended there, all remaining in close dependence upon the whole structure. After this, there will remain for us to observe how masses, both inorganic and organic, are distributed naturally in or on the earth, as masses, in order to be prepared to enter, in a methodical way, upon the study of sociological limits and boundaries which form a special and more complex case of those already given.
SECTION VI. ANTHROPOLOGICAL LIMITS.
The human species belongs to the class of superior verte- brates. The skeleton determines the general form of our bodies. It serves as a point of attachment for the muscles and deter- mines the visceral cavities. We have explained how the struc-
