two constitutive factors, and of the actions, reactions, and combinations which are the consequence of this juxtaposition, it forms a social substance, an aggregate. However, as we have already indicated, this idea of the social aggregate, such as it is, is not yet sufficient to permit us to advance by it alone to the conception of social structure, of social statics, of equilibrium. Up to this point, we know only the social mass composed of different parts and endowed with a certain. number of properties. In order to advance to the comprehension of the idea of structure, there is needed the supplementary notion of a certain arrangement of the constitutive parts of the aggregate. This arrangement must be such that the social mass can hold itself in equilibrium, not merely in a state of repose, which is only an abstraction, but also in a state of movement, which is the other inseparable aspect of life.
The simplest, the most general arrangement for every social aggregate is that which results from a differentiation between its mass, composed of the elements which we know, and the external environment. We temporarily neglect the latter in order that we may consider the internal arrangement of the parts in relationship to the structure and the service of the whole. A substance may be called organized when it is composed of simple elements more or less numerous, and united by special combination and reciprocal dissolution. This is the character of the simplest, most elementary organic order. However, in general, each anatomical element possesses also another characteristic of organic order, a characteristic that is found only in living bodies; this is the possession of a structure, of a function. Structure implies, then, a correlated arrangement, with mediate or immediate continuity, of the particular organs, groups of organs, and systems constitutive of the general structure. Matter called organic is in reality organized only when there is structure, that is to say, a determined juxtaposition of matter organically differentiated.
Likewise in sociology the mass or aggregate may be considered as superorganic whenever it is composed of inorganic, organic, and psychic factors combined, and therefore necessarily
