Organic nature, through the course of development, and under the influence of inhibitive or favourable factors, creates in the masses of individuals to which she gives birth differences and differentiations—differences of sex, of intellectual and æsthetic capacity, of character, etc. Thus she gives opportunity for the origination of certain social phenomena; for society offers a field abounding in opportunities for the activity of the most extensive differences of natural endowment. But society provides also selective factors, and thereby alters the constitution and composition of the materials furnished by nature in the most manifold variety. Thus, more or less rapidly, the race undergoes modification. This reciprocal action is the province in which nature and society meet, and in which social polity has to receive guidance from anthropology and biology. I consider that Lombroso has proved by a rigid induction that nature has endowed man at birth with social sentiments, or—which amounts to the same thing—with an organic predisposition, out of which, in the course of individual development, social sentiments arise; and that inheritance and fœtal development determine whether the individual is in a position to guard and to further his own interests in the communal life without prejudice to the interests of the community. In this connection he has most carefully investigated two special instances: first, that category of individuals who have needs and impulses incapable of satisfaction without severe injury to the interests of the community or to the social standards—criminals and prostitutes; and secondly, those who consider that the permanent or future interests of the community cannot be secured without infraction of the traditional forms of social life, or, perhaps, without disregard of formal legal prohibitions, without “breaking the old tables,” without “revaluation of old values”—geniuses and “political criminals.” He has, however, also demonstrated the fact that in relation to the rigidity—the formalism—with which the traditions of the social order have hitherto always been preserved, and will continue to be preserved in the future, society itself is not as a rule in a position to distinguish between the criminal and the useful revolutionary. This is made manifest by the study of the researches undertaken by Lombroso for his description of the political criminal (1890) and of anarchism (1849). His examination of the part played in social life by the political or social genius leads him to formulate a theory regarding the acceleration of social evolution. Genius brings to pass the revolution for which the way has been prepared by evolution; the criminal merely produces revolts.