There still seemed to be a possibility of proving the backwardness of certain tribes, if it could be shown that members of certain races were all on early levels of culture, while those of other races had independently reached later stages of development. This would presuppose that the general course of cultural development is the same everywhere, and that types of culture can be ascribed to definite stages of development. The theory of such general parallelism of the history of human culture is based on the similarity of cultural traits in all parts of the world. Our analysis showed that the similarities were more apparent than real, that they often developed by convergent development from distinct sources, and that not all stages have been present in all types of cultures. Thus all attempts to correlate racial types and cultural stages failed us, and we concluded that cultural stage is essentially a phenomenon dependent upon historical causes, regardless of race. Finally we attempted to describe the mental characteristics of primitive man, regardless of his racial affiliations. We pointed out the differences in principles of classification of experience found on different social stages, and the differences in logical conclusions reached by primitive and civilized man owing to the difference in the character of knowledge accumulated by preceding generations. We then followed out the emotional associations of habitual activities, and the tendency to invent for them rationalistic explanations. We found them quite common in primitive life, and noticed the great variety of ideas and activities that were thus brought into contact so as to produce a number of peculiar concepts and activities. Other peculiar associations are not due to strong emotional causes, but to all of them is common the tendency of taking on rationalistic explanations of varied character. The change from primitive to civilized society includes a lessening of the number of the emotional associations, and an improvement of the traditional material that enters into our habitual mental operations. ------------------------------------------------------------------------ X. RACE PROBLEMS IN THE UNITED STATES WE will now turn to the question what these results of our inquiry teach us in regard to the problems that confront our modern civilization, particularly our nation. The development of the American nation through the amalgamation of diverse European nationalities, the presence of the Negro, Indian, and Chinese, and the whole ever-increasing heterogeneity of the component elements of our people, involve a number of problems to the solution of which our inquiries contribute important data.