the environment in which the English have evolved has so differed from the environments in which the French, the Italians, the Germans, and the West Africans have evolved, that survival of the fittest, in the case of the Englishman, has caused in them a greater evolution of the nervous structures which subserve resolution than it has caused in the other nations named; it can hardly be that the Frenchman is inherently vain because the environment of his ancestry was such that superior vanity caused a greater survival or a lesser elimination than it caused in the other nations; there is no conceivable reason why phlegm in Germanic surroundings should have conduced to survival more than in West African surroundings; or why cruelty should have been more beneficial or less deleterious to the ancestors of the West Africans than it was to the ancestors of the Germans.
We must suppose, therefore, that differences in the sizes and shapes of the brains of various races imply, not differences in inborn mental traits, but differences in the power of acquiring traits; we must conclude that the African Bushman, with his small brain, differs mentally from the Englishman with his large brain, not mainly in inborn mental traits, but mainly in the traits which he acquires, and in his powers of acquiring them. Reasoning from the analogy of lower animals, it is certain that the man with the smaller and less developed brain differs inherently from the man with the larger and better developed brain, mainly in that he has a smaller power of developing in response to stimulation, a lesser power of acquiring fit mental traits, not mainly in that he has different inborn mental traits, for these latter (i.e. instincts), as I say, have been so replaced and overshadowed in man by acquired mental traits, that they have undergone great retrogression, and except as regards certain instincts, common to all
