found out before we can speak with any certainty as to whether some changes mean the actual dying out or the mere transformation of types. It is, for instance, astonishing how little permanent change in the physical make-up of the people seems to have been worked in Europe by the migrations of the races in historic times. A tall, fair-haired, long-skulled race penetrates to some southern country and establishes a commonwealth. The generations pass. There is no violent revolution, no break in continuity of history, nothing in the written records to indicate an epoch-making change at any given moment; and yet after a time we find that the old type has reappeared and that the people of the locality do not substantially differ in physical form from the people of other localities that did not suffer such an invasion. Does this mean that gradually the children of the invaders have dwindled and died out; or, as the blood is mixed with the ancient blood, has there been a change, part reversion and part assimilation, to the ancient type in its old surroundings? Do tint of skin, eyes and hair, shape of skull, and stature, change in the new environment, so as to be like those of the older people who dwelt in this environment? Do the intrusive races, without change of blood, tend under the pressure of their new surroundings to change in type so as to resemble the ancient peoples of the land? Or, as the strains mingled, has the new strain dwindled and vanished, from causes as yet obscure? Has the blood of the Lombard practically disappeared from Italy, and of the Visigoth from Spain, or does it still flow in large populations where the old physical type has once more become dominant? Here in England, the long-skulled men of the long barrows, the short-skulled men of the round barrows, have they blended, or has one or the other type actually died out; or are they merged in
