Migration to other countries has also been adduced as one of the causes of variety in mankind; but the permanency of the characteristic distinctions of any race militates against this supposition. The physical character of the Celts, who peopled the west of Europe at an early period, is still observable in the Spaniard, most of the French, the native Welsh, the Manks, and the Scotch Highlander; whereas the German race, who occupied the more northern and eastern settlements, are still distinguished by their transparent skin, rosy complexion, flaxen hair, and blue eyes; and in Ireland, the race of the Danes and the Milesians can to this day be recognised in their respective characters. Shaw and Bruce traced the descendants of the Vandals who passed from Spain into Africa in the fifth century; and, after a lapse of thirteen centuries, Bruce says that they are "fair like the English, their hair red, and their eyes blue." Negroes have been introduced into the New World for upwards of three centuries, where, despite of a new clime and different habits, they still retain the character of their race; and the Jews who have not intermarried out of their nation, have preserved their features for nineteen centuries. Not only do we observe the peculiarities of physical conformation resisting the destructive or degenerating hand of time, but certain imperfections in their faculties have been equally permanent in certain tribes. It is a curious fact that the Mamelukes, who have resided in Egypt for upwards of five hundred and fifty years, have never perpetuated their subsisting issue. Volney observed, that there does not exist one single family of them in the second generation; all their children perishing in the first or second descent. The same observation applies to the Turks, who can only secure the continuance of their families by marrying native women, an union which the Mamelukes disdained. This singularity, remarked by Volney, has been since confirmed by late travellers.