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

Geologists are rapidly becoming convinced that the mammals spread from their central Asian point of origin largely because of great variations in climate.

Year by year we are learning that in this restless, strenuous American life of ours vacations are essential.

Although mountains may guide migrations, the plains are the regions where people dwell in greatest numbers.

Although farming of any sort was almost as impossible in the plains as in the dry regions of winter rains farther west, the abundance of buffaloes made life much easier in many respects.

No part of the world can be truly understood without a knowledge of its garment of vegetation, for this determines not only the nature of the animal inhabitants but also the occupations of the majority of human beings.

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.