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.
The evidence points to central Asia as man's original home, for the general movement of human migrations has been outward from that region and not inward.
The human organism inherits so delicate an adjustment to climate that, in spite of man's boasted ability to live anywhere, the strain of the frozen North eliminates the more nervous and active types of mind.
The Indians could not undertake any widespread cultivation of the plains not only because they lacked iron tools but also because they had no draft animals.
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.
Today, no less than in the past, the tetrahedral form of the earth and the relation of the tetrahedron to the poles and to the equator preserve the conditions that favor rapid evolution.
