[27] Societies and civilisations, the associations of bees and ants, or the Modern State, obviously exhibit this differentiation. It is morphological and functional in the case of the Arthropods, since individuals performing different duties are modified in form. It is functional only in the case of human societies. Integration of the activities of the individuals in both kinds of societies is effected by inter-communication: articulate symbols in the case of the lower animals, language in the case of man. If the concept of “orders of individuality” were anything more than a convenient, though artificial, analysis of naturally integral entities, we might speak of the ideal state or the insect society as a “fourth order of individuality.” In the process of organic growth the relation between mass and form no longer holds in all the exactness with which it applies to the growth of the crystal. We might spend a lifetime growing tablets of cane-sugar, but in all cases we should find that the mass of any crystal was proportional to the cube of a length of a diameter: there would be a strict relation between mass and geometrical form. But this strict relation does not hold in the case of a series of organisms belonging to the same species but differing in size. If we measure, for instance, the lengths of a great number of fishes of the same species, we should find that we must describe the law of growth, not by the simple equation _M_ = _al_^3, but by an empirically evaluated expression of the form _M_ = _a_ + _bl_ + _cl_^2 + _dl_^3 + ... and that the constants in this equation would vary with the species studied and with the conditions in which it is living--that is, the organism changes in form as it increases in size. This is inconceivable in the case of purely physical growth by the accretion of molecules, and we find again that the characters of the organism depend not only on what it is but also upon what it has been--that is, upon its duration. Growth, then, in plants and animals implies variability in form, in general cumulative variability, leading to an indefinite departure from the typical form.