blood as by the imposition on the less civilized race of the type characteristic of the more advanced. The Slavs who entered Hellas in and after the eighth century have become Greeks; and the Albanian Toskhs who moved southward later are now also virtually Greeks, though so far south as Eleusis they spoke Albanian into our own time.
The race that accepts an alien type may be the stronger race in everything but intelligence and culture. Sometimes strength, if it take the form of a dogged persistence in its ancient ways, is the undoing of a people. Many of the Red Indian tribes have perished off the earth because they could not or would not adjust themselves to the conditions which the advent of the whites imposed. The black man submits and survives.
Through these two processes of Extinction and Absorption an enormous change has passed upon the population of the globe. More than half of the tribes or peoples that existed when authentic history begins would seem to have vanished. There must have been, at a remote epoch, a process of differentiation, whereby first the great families of mankind, and then the subdivisions of those families, were under the influence of their physical environment acquiring those definite characteristics which distinguish from one another those that still remain. This process must have required untold ages: and it doubtless continued in some parts of the world, while in others the opposite process of reducing the number of types through the killing off or assimilation of the weaker had already begun.
