Notwithstanding the numerous attempts that have been made to find structural differences between the brains of different races of man that could be directly interpreted in psychological terms, no conclusive results of any kind have been attained. The status of our present knowledge has been well summed up by Franklin P. Mall, to whose investigation I referred before. He holds, that, on account of the great variability of the individuals constituting each race, racial differences are exceedingly difficult to discover, and that up to the present time none have been found that will endure serious criticism. We may now sum up the results of our preliminary inquiry. We have found that the unproved assumption of identity of cultural achievement and of mental ability is founded on an error of judgment; that the variations in cultural development can as well be explained by a consideration of the general course of historical events without recourse to the theory of material differences of mental faculty in different races. We have found, furthermore, that a similar error underlies the common assumption that the white race represents physically the highest type of man, but that anatomical and physiological considerations do not support these views. ----- Footnote 1: For authorities, see note to this page at end of book. ------------------------------------------------------------------------ II. INFLUENCE OF ENVIRONMENT UPON HUMAN TYPES AFTER having seen that the high estimate of our civilization does not necessarily imply that the carriers of this civilization have an anatomical organization superior to that of all other races, we may turn our attention to a closer investigation of the characteristics of different divisions of mankind. It is clear that our investigations cannot be based on vague descriptions of travellers,—who remark upon the enormous digestive organs of primitive man, or on his small size, or on the lack of development of his limbs, or even upon his resemblance to apes,—but on serious studies of anatomical characteristics.