There can, I think, be no reasonable doubt that there are great differences between races, and that these may be, and in many cases have been, persistent through thousands of generations. The recognition that the mind of the human infant is not a _tabula rasa_, but that its innate constitution comprises a number of instincts, specifically directed tendencies to thought, feeling, and action, prepares us to accept this view and gives us some basis for the definition of these differences. Whether all differences can be defined in such terms is a further problem. That they cannot be wholly defined in this way seems to be obvious, when we consider how quite specialised idiosyncrasies are transmitted in families through several generations, often with a leap across one generation, peculiarities of taste and feeling, of aesthetic endowment and temperament, abilities such as the musical, mathematical and artistic. When we compare widely different peoples such as the Negro, the White, and the Yellow, the fact of profound differences cannot be overlooked. These differences cannot be ascribed to the action of environment upon each generation. Perhaps the only differences of this kind which at present are accurately measurable are those of the size and form of the brain. The negro brain is decidedly smaller than that of the white and yellow races. And there are small but distinct differences of sensory endowment which are highly significant. For, if there are racial differences in these most fundamental and racially oldest endowments, we may expect still greater differences in the later evolved powers of the mind; although these are much more difficult to detect and define. Still, the negro race wherever found does present certain specific mental peculiarities roughly definable, especially the happy-go-lucky disposition, the unrestrained emotional violence and responsiveness, whether its representatives are found in tropic Africa, in the jungles of Papua, or in the highly civilised conditions of American cities.