The difference between prehistoric Europe and the present state of these peoples resolves itself on analysis into a difference in the state of the industrial arts, together with such institutional changes as have come on in the course of working out this advance in the industrial arts. The habits and the exigencies of life among these peoples have greatly changed; whereas in temperament and capacities the peoples that now live by and under the rule of this altered state of the industrial arts are the same as they were. It is to be noted, therefore, that the fact of their having successfully come through the long ages of prehistory by the use of this mental and spiritual endowment can not be taken to argue that these peoples are thereby fit to meet the exigencies of this later and gravely altered age; nor will it do to assume that because these peoples have themselves worked out this modern culture and its technology, therefore it must all be suitable for their use and conducive to their biological success. The single object lesson of the modern urban community, with its endless requirements in the way of sanitation, police, compulsory education, charities,--all this and many other discrepancies in modern life should enjoin caution on anyone who is inclined off-hand to hold that because modern men have created these conditions, therefore these must be the most suitable conditions of life for modern mankind. In the beginning, that is to say in the European beginning, men lived in small and close groups. Control was close within the group, and the necessity of subordinating individual gains and preferences to the common good was enjoined on the group by the exigencies of the case, on pain of common extinction. The situation and usages of existing Eskimo villages may serve to illustrate and enforce the argument on this head. The solidarity of sentiment necessary to support the requisite solidarity of action in the case would be a prime condition of survival in any racial stock exposed to the conditions which surrounded these early Europeans. This needful sense of solidarity would touch not simply or most imperatively the joint prestige of the group, but rather the joint material interests; and would enforce a spirit of mutual support and dependence. Which would be rather helped than hindered by a jealous attitude of joint prestige; so long as no divergent interests of members within the group were in a position to turn this state of the common sentiment to their own particular advantage.