After having thus found an answer to our first problem, we turn to the second one: In how far are we justified in considering those anatomical traits in regard to which foreign races differ from the white race as marks of inferiority? In one respect the answer to this question is easier than that to the former. We have recognized that achievement alone does not justify us in assuming greater mental ability for the white race than for others, unless we can sustain our claim by other proofs. It follows from this, that differences between the white race and other races must not be interpreted to mean superiority of the former, inferiority of the latter, unless this relation can be proved by anatomical or physiological considerations. It may not be amiss to illustrate by an example the logical error which is committed with great ease and great frequency. In a painstaking investigation made a few years ago, Mr. R. B. Bean demonstrated certain characteristic differences between the form of the whole and of the parts of the brain of the Baltimore negro and of the Baltimore white,—differences which consist in the form and relative size of the frontal and occipital lobes and in the size of the _corpus callosum_. The interpretation of the difference is, that the smaller size of the anterior lobes and of the _callosum_ indicates a lower mental development, a conclusion which has been refuted by Franklin P. Mall. It may suffice here, where we are interested chiefly in the logical fallacy of such conclusions, to call attention to the fact that a comparison of long-headed and short-headed individuals of the same race—or, let us say, of long-headed North French and of short-headed Central French—would result in similar differences, but that in a case of this kind the inference regarding greater or lesser ability would not be made with the same readiness. There is, of course, no doubt that great differences exist in the physical characteristics of the races of man. The color of the skin, the form of the hair, and the configuration of lips and nose, distinguish the African clearly from the European. The question to decide is, What relations have these features to the mental aptitude of a race? Two points of view may be brought forward in relation to this question. First, we may claim that a race in which peculiarities are found that are characteristic of lower stages in the animal series will be in all respects of an inferior type. Secondly, we may direct our attention primarily to the central nervous system and investigate whether the anatomical structure in one race is superior to that found in another race.