With every throb of the climatic pulse which we have felt in Central Asia,, the centre of civilisation has moved this way and that. Each throb has sent pain and decay to the lands whose day was done, life and vigour to those whose day was yet to be.

In fact, the history of North America has been perhaps more profoundly influenced by man's inheritance from his past homes than by the physical features of his present home.

For the source of any characteristic so widespread and uniform as this adaptation to environment we must go back to the very beginning of the human race.

Man could not stay there forever. He was bound to spread to new regions, partly because of his innate migratory tendency and partly because of Nature's stern urgency.

Thus the races, though alike in their physical response to climate, may possibly be different in their mental response because they have approached America by different paths.

We are learning, too, that the love of beauty is one of Nature's greatest healers.

History in its broadest aspect is a record of man's migrations from one environment to another.