We cannot fully understand the matter and the manner of this investigation unless we are acquainted with certain earlier writings of Lombroso’s, and more especially with his researches concerning the nature of genius; it is necessary also to give an anticipatory account of his ideas concerning the nature of revolution. “Revolution is the historical expression of evolution; it is the chicken which has outgrown the embryonic stage, and is ready for life in the open, breaking through the shell.” This is a metaphor to which Lombroso returns again and again. If the new development is one with whose idea the generality have become familiar, if the old forms have become rotten, the evolutionary impulse spontaneously breaks into fresh channels. It is true that even then in some cases some force has to be applied to overcome the resistance of the adherents of the old ways; for, owing to the universality of misoneism, and to the law of inertia, such adherents will always be found, however cogent the need for innovation. Now, the characteristic of genius is its freedom from that which furnishes obstacles to progress, its freedom from misoneism—at least, in respect of progress in that particular direction towards which the particular type of genius is directed. In genius, therefore, Lombroso recognizes at once the source of all those tendencies which gradually swell to form the irresistible flood of revolution, and the helper through whose instrumentality the ultimately mature embryo is assisted to its birth. And just as, on the one hand, the genius accompanies a genuine revolutionary movement, one capable of development, from its first small beginnings down to its victorious close; so, on the other hand, the pseudo-genius, the “mattoid” criminal or the lunatic, excites revolts which oppose themselves in vain to the _vis inertiæ_ of society, and whose sole result is to hinder the general course of evolution. In this section of this remarkable book we find a notable stimulus, and the brilliant exposition leads us to formulate all kinds of speculation. We are induced to attempt also to draw up a prognosis. We ask ourselves what will be the outcome of such a movement as that which was initiated in Germany by Lassalle—half genius, half-moral eccentric—a movement which has found its fool and its half-fool in Neve and Most respectively, and among whose adherents even now the question is being discussed whether the old Prussian suffrage system shall be and can be destroyed and rebuilt by means of street-demonstrations and the general strike.