It is, therefore, no difference of aboriginal outfit, but a difference in the chances of migration and situation, which accounts for the cultural diversity of races. Yet we must not at once infer that any lower race can, on this account, be drawn from its isolation and lifted to the higher level. There is reason to believe that a race loses its educability if it remains unprogressive for too long a period. The physiological reason may be that the skull closes firmly, at a relatively early age, over the brain in a people in which expansion of brain after puberty has not been encouraged. Take the three "lower races" of Australasia. The Tasmanian was one of the oldest and least cultured branches of the human family, and he died out within a century after contact with the whites. The Maori of New Zealand is the most recent and most advanced of the three aboriginal races. With the Polynesian, he is closely related to the European or Caucasic race, and is certainly educable. The Australian black comes between the two in culture and in the period of his isolation. Australian scientific men who have made the most sympathetic efforts to uplift the black tell me that they have failed, and the race seems to be doomed. These scientific principles have discredited the old legendary notions about the lower races, but we must not as yet make dogmas of them. Nothing but candid and careful experience will show which races are educable and which ineducable. It is very probable that such peoples as the wild Veddahs of Ceylon, the Aetas of the Philippines, the Yahgans of Tierra del Fuego, and some of the Central African groups, will prove ineducable. Other races which have been considered "savage" are already proving educable, either as a body or in large numbers of instances. Many peoples have not been tested at all. We are only just at the fringe of this vast and interesting problem.