Cases of permanence of type and language and of change of culture are much more numerous. As a matter of fact, the whole historical development of Europe, from prehistoric times on, is one endless series of examples of this process, which seems to be much easier, since assimilation of cultures occurs everywhere without actual blood-mixture, as an effect of imitation. Proof of diffusion of cultural elements may be found in every single cultural area which covers a district in which many languages are spoken. In North America, California offers a good example of this kind; for here many languages are spoken, and there is a certain degree of differentiation of type, but at the same time a considerable uniformity of culture prevails (Kroeber). Another case in point is the coast of New Guinea, where, notwithstanding strong local differentiations, a certain fairly characteristic type of culture prevails, which goes hand in hand with a strong differentiation of languages. Among more highly civilized peoples, the whole area which is under the influence of Chinese culture might be given as an example. These considerations make it fairly clear that, at least at the present time, anatomical type, language, and culture have not necessarily the same fates; that a people may remain constant in type and language, and change in culture; that it may remain constant in type, but change in language; or that it may remain constant in language, and change in type and culture. It is obvious, therefore, that attempts to classify mankind, based on the present distribution of type, language, and culture, must lead to different results, according to the point of view taken; that a classification based primarily on type alone will lead to a system which represents more or less accurately the blood-relationships of the people, which do not need to coincide with their cultural relationships; and that in the same way classifications based on language and culture do not need at all to coincide with a biological classification. If this be true, then a problem like the Aryan problem, to which I referred before, really does not exist, because the problem is primarily a linguistic one, relating to the history of the Aryan languages; and the assumption that a certain definite people whose members have always been related by blood must have been the carriers of this language throughout history, and the other assumption, that a certain cultural type must have always belonged to this people,—are purely arbitrary ones, and not in accord with the observed facts.