When this point of view is taken, the question, of course, arises whether the problem thus assigned to folk psychology is not already being solved by ethnology, the science of peoples, or whether it ought not to be so solved. But it must be borne in mind that the greatly enlarged scope of modern ethnology, together with the increased number and the deepened character of its problems, necessarily precludes such a psychological investigation as falls to the task of folk psychology. I may here be allowed to refer to one who, perhaps more than any other recent geographer, has called attention to this extension of ethnological problems--Friedrich Ratzel. In his treatise on anthropography and in a number of scattered essays on the cultural creations of peoples, Ratzel has shown that ethnology must not only account for the characteristics and the habitats of peoples, but must also investigate how peoples originated and how they attained their present physical and mental status. Ethnology is the science of the origin of peoples, of their characteristics, and of their distribution over the earth. In this set of problems, psychological traits receive a relatively subordinate place. Apparently insignificant art products and their modifications may be of high importance in the determination of former migrations, fusions, or transferences. It is in this way that ethnology has been of valuable service to history, particularly in connection with prehistoric man. The central problem of ethnology concerns not only the present condition of peoples, but the way in which they originated, changed, and became differentiated. Folk psychology must be based on the results of ethnology; its own psychological interest, however, inclines it to the problem of mental development. Though of diverse origins, peoples may nevertheless belong to the same group as regards the mental level to which they have attained. Conversely, peoples who are ethnologically related may, psychologically speaking, represent very different stages of mental culture. The ethnologist, for example, regards the Magyars and the Ostiaks of Obi as peoples of like origin. Psychologically, they belong to different groups: the one is a cultural people, the other is still relatively primitive. To the folk psychologist, however, 'primitive' always means the psychologically primitive--not that which the ethnologist regards as original from the point of view of the genealogy of peoples. Thus, folk psychology draws upon ethnology, while the latter, in turn, must invoke the aid of the former in investigating mental characteristics. The problems of the two sciences, however, are fundamentally different.