It will be a vast boon to mankind when we learn to prophesy the precise dates when cycles of various kinds will reach definite stages.

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.

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.

Nevertheless most of the evergreen forests of the north must always remain the home of wild animals and trappers, a backward region in which it is easy for a great fur company to maintain a practical monopoly.

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.

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

The whole history of life is a record of cycles.