What is specially characteristic of human life, however, is the presence of mind, both in its lower and in its higher phases; and the science that deals with mind will have to be appealed to in the course of our treatment. The appetites, the instincts and the emotions cannot be ignored in considering the growth and activities of human societies. These aspects of human nature are commonly studied by psychologists in their more purely individual manifesta tions; but social psychology is now recognized as an important branch of study.1 What has been called crowd psychology is a special aspect of it; 2 and the study of language may be regarded as another.3 The control and modification of the more purely animal elements in human nature has to be specially considered in dealing with human society. The theory of education is important for our purpose, in so far as it traces the processes by which the individual, partly by natural growth and partly by external guidance, is developed into a responsible member of a community, fulfilling definite functions in its life.