After we have thus found that the alleged specific differences between civilized and primitive man, so far as they are inferred from complex psychic responses, can be reduced to the same fundamental psychical forms, we have the right to decline as unprofitable a discussion of the hereditary mental traits of various branches of the white race. Much has been said of the hereditary characteristics of the Jews, of the Gypsies, of the French and Irish, but I do not see that the external and social causes which have moulded the character of members of these people have ever been eliminated satisfactorily; and, moreover, I do not see how this can be accomplished. A number of external factors that influence body and mind may easily be named,—climate, nutrition, occupation,—but as soon as we enter into a consideration of social factors and mental conditions, we are unable to tell definitely what is cause and what is effect. An apparently excellent discussion of external influences upon the character of a people has been given by A. Wernich in his description of the character of the Japanese. He finds some of their peculiarities caused by the lack of vigor of the muscular and alimentary systems, which in their turn are due to improper nutrition; while he recognizes as hereditary other physiological traits which influence the mind. And still, how weak appear his conclusions, after the energy and endurance exhibited by the Japanese in their modern development and in their conflict with Russia! Effects of malnutrition continued through many generations might be expected to affect the mental life of the Bushmen and the Lapps (Virchow); and still, after the experience just quoted, we may well hesitate before we express any definite conclusions. It would seem, therefore, that we have no right to explain difference in mental attitude of different groups of people, particularly of closely related ones, as due to hereditary causes, until we have been able to prove that physiological and the correlated psychological traits are hereditary, regardless of social and natural environment. A beginning in work of this kind has been made in the experimental investigations of school-children in regard to simple mental activities and simple physiological processes; in the work of the Cambridge Scientific Expedition to Torres Strait (Rivers), in which the first systematic attempt has been made to study the simple psychical re-actions of primitive people; and in the investigations carried on systematically by Dr. Woodworth on the primitive people exhibited at the World’s Fair of St. Louis. Up to this time the results are, on the whole, not favorable to the theory of the occurrence of very fundamental differences between different races.