The whole history of life is a record of cycles.

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.

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.

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

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.

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

America forms the longest and straightest bone in the earth's skeleton.