ultimately decadent group is a commonplace of history. In highly segregated peoples the restrictive effect of the social instinct upon personality has usually been to some extent relaxed, and a relatively rich personal development has been possible. Such an amplification has always, however, been limited to privileged classes, has always been accompanied by a weakening of the national bond, and a tendency of the privileged class to the sincere conviction that its interests are identical with those of the nation. No nation has ever succeeded in liberating the personality of its citizens from the restrictive action of the social instinct and at the same time in maintaining national homogeneity and common impulse. In a small community intercommunication among its individual members is free enough to keep common feeling intense and vigorous. As the community increases in size the general intercommunication becomes attenuated, and with this common feeling is correspondingly weakened. If there were no other mechanism capable of inducing common action than the faint social stimulus coming from the nation at large, a segregated society would be incapable of national enterprise. There is, however, another mechanism which we may call leadership, using the word in a certain special sense. All social groups are more or less capable of being led, and it is manifest that the leadership of individuals, or perhaps more usually of classes, has been a dominant influence in the expansion and enterprise of all civilizations of which we have any knowledge. It is only in the small communities that we can detect evidence of a true common impulse shared alike by all the members acting as the cause of expansion. In larger groups, {247} autocracies and dynasties, Pharaohs and Nebuchadnezzars have imposed the impulse of expansion upon the people, and by virtue of human susceptibility to leadership have secured a virtual, though only a secondary, common purpose.