have suddenly run up against one another along a racial frontier. Such was the old-fashioned view of races in the days before the theory of evolution had remodeled our ways of thinking, when human races were held to be distinct creations of a Divine will. We conceive of it all quite differently. These types for us are all necessarily offshoots from the same trunk. The problem is far m.ore complex to us for this reason. It is doubly dynamic. Up-building and demolition are taking place at the same time. By our constitution of racial types we seek to simplify the matter—for a moment to lose sight of all the destructive forces, and from obscure tendencies to derive ideal results. We picture an anthropological goal which might have been attained had the life conditions been less complicated.
Are we in this more presumptuous than other natural scientists? Is the geologist more certain of his deductions in his restoration of an ideal mountain chain from the denuded roots which alone bear witness to the fact to-day? In this case all the superstructure has long since disappeared. The restoration is no less scientific. It represents more clearly than aught else the rise and disappearance, the results and future tendencies of great geological movements. We take no more liberties with our racial types than this geologist with his mountains; nor do we mean more by our restorations. The parallel is instructive. The geologist is well aware that the uplifted folds as he depicts them never existed in completeness at any given time. He knows full well that erosion took place even as lateral pressure raised the contorted strata; that one may even have been the cause of the other. If indeed denudation could have been postponed until all the elevation of the strata had been accomplished, then the restoration of the mountain chain would stand for a real but vanished thing. This, the geologist is well aware, was not thus and so. In precisely the same sense do we conceive of our races. Far be it from us to assume that these three races of ours ever in the history of mankind existed in absolute purity or isolation from one another. As soon might the branch grow separate and apart from the parent oak. No sooner have environmental influences, peculiar habits of life, and artificial selection commenced to generate distinct varieties of men from the common clay; no sooner has heredity set itself to perpetuating these; than chance variation, migration, intermixture, and changing environments, with a host of minor dispersive factors, begin to efface this constructive work. Racial up-building and demolition, as we have said, have ever proceeded side by side. Never is the perfect type in view, while yet it is always possible. "Race," says Topinard, "in the present state of things is an abstract conception, a notion of continuity in discontinuity, of unity in diversity. It is the rehabilitation of a real
