History traces the evolution of the social structure in which the community exists to-day. There are three chief factors at work in this evolution; racial descent, culture drift, and transmission of language: the first of these physiological and not necessarily connected with the other two, whilst those two are not always associated with each other. In the evolution of the social structure the factor of first importance is the transmission of culture, which is not a matter of heredity but due to contact, for culture is learned and reproduced by imitation and not inherited. Culture must be...