Taking these two points separately, I hold it to be a statement opposed to fact to say, or to imply, that all existing savages, when not brought into contact with civilized man, undergo intellectual development from generation to generation. On the contrary, one of the most generally applicable statements we can make with reference to the psychology of uncivilized man is that it shows, in a remarkable degree, what we may term a _vis inertiæ_ as regards upward movement. Even so highly developed a type of mind as that of the Negro—submitted, too, as it has been in millions of individual cases to close contact with minds of the most progressive type, and enjoying as it has in many thousands of individual cases all the advantages of liberal education—has never, so far as I can ascertain, executed one single stroke of original work in any single department of intellectual activity. Again, if we look to the whole history of man upon this planet as recorded by his remains, the feature which to my mind stands out in most marked prominence is the almost incredible slowness of his intellectual advance, during all the earlier millenniums of his existence. Allowing full weight to the consideration that “the Palæolithic age, referring as the phrase does to a stage of culture, and not to any chronological period, is something which has come and gone at very different dates in different parts of the world;”[9] and that the same remark may be taken, in perhaps a smaller measure, to apply to the Neolithic age; still, when we remember what enormous lapses of time these ages may be roughly taken to represent, I think it is a most remarkable fact that, during the many thousands of years occupied by the former, the human mind should have practically made no advance upon its primitive methods of chipping flints; or that during the time occupied by the latter, this same mind should have been so slow in arriving, for example, at even so simple an invention as that of substituting horns for flints in the manufacture of weapons. In my next volume, where I shall have to deal especially with the evidence of intellectual evolution, I shall have to give many instances, all tending to show its extraordinarily slow progress during these æons of pre-historic time. Indeed, it was not until the great step had been made of substituting metals for both stones and horns, that mental evolution began to proceed at anything like a measurable rate. Yet this was, as it were, but a matter of yesterday. So that, upon the whole, if we have regard to the human species generally—whether over the surface of the earth at the present time, or in the records of geological history,—we can no longer maintain that a tendency to improvement in successive generations is here a leading characteristic. On the contrary, any improvement of so rapid and continuous a kind as that which is really contemplated, is characteristic only of a small