We have seen that in all gregarious animals the social instinct must follow one of three principal types, each of which will produce a herd having special activities and reactions. The major units of the human species appear limited to a similar number of categories, but it is probable that the perpetuation of a given type in a given herd is not chiefly a matter of heredity in the individual. The individual is gregarious by inheritance; the type according to which his gregarious reactions are manifested is not inherited, but will depend upon the form current in the herd to which he belongs, and handed down in it from generation to generation. Thus it has happened that nations have been able in the course of their history to pass from the aggressive to the socialized type. The change has perhaps been rendered possible by the existence of class segregation of a not too rigid kind, and has doubtless depended upon a progressive intercommunication and the consequently developing altruism. The extremely rigid Prussian social system seems clearly to be associated with the persistence of the aggressive form of society. In considering the permanent deliverance of Europe from the elements in Germany for which {198} there can be no possible toleration, we therefore have not to deal with characters which must be regarded as inherited in the biological sense. We have to deal rather with a group of reactions which, while owing their unity, coherence, and power to the inherited qualities of the gregarious mind, owe their perpetuation to organized State suggestion, to tradition, and to their past success as a national method.