For example, people whose ancestors, through countless ages, lived in the bright sunlight and tropical luxuriance of the warmer climes, have dark eyes, dark hair, and dark skin because nature found it necessary to supply an abundance of pigmentation in order to protect the delicate tissues of the body from injury by the actinic rays of the sun.  The same soft luxuriance of their environment has made these people slow, easy-going, hateful of change, introspective, philosophical and religious.  On the other hand, people whose ancestors dwelt for centuries in the cold, dark, cloudy and foggy climate of Northwestern Europe have less need for pigmentation and are, therefore, flaxen-haired, blue-eyed and white-skinned.

The hardships and rigors of this Northern climate made these people aggressive, active, restless, fond of variety, and, because of their fierce struggle for existence, exceedingly practical, matter-of-fact, and material.

WHY NOSES DIFFER IN SIZE AND SHAPE

Another example illustrates this truth clearly:  The type of human nose evolved in warm, humid climates is low and flat, with large, short passageways directly to the lungs.  People living in such a climate have little need for great energy and activity, since there is food in abundance all around them.  On the other hand, the type of nose evolved in a cold, dry climate is high in the bridge, with thin nostrils, so that the air may be both warmed and moistened before reaching the lungs.  People living in such a climate have great need for activity, both in order to secure the means of subsistence and in order to keep themselves warm.  Thus we find that the low, flat nose is everywhere the nose of indolence and passivity, while the large nose, high in the bridge, is everywhere an indication of energy and aggressiveness.

WHY SOME HEADS ARE HARD, OTHERS SOFT

In brief, then, darkness of color is not the cause of deliberation and conservatism, but both darkness of color and conservatism are results of the same causes, namely, a heredity and environment which produce these characteristics.  Blonde coloring is not a cause of restless activity, but both the color and the activity are the result of evolution in a cold, dark, rigorous climate.

A striking example of the working out of the three truths which we have given is seen in the consistency of the body.  Hard hands, hard muscles, and, in general, a dense, compact, unyielding consistency of fiber, are both inherited and acquired as the result of hard physical labor and the enduring of hardships.  As is well known, those who spend their lives in grinding toil in the midst of hard conditions care little for the finer sentiments and sympathies of life.  They have no time for them, no energy left for them.  By the very necessities of their lot they are compelled to be hostile to change, free from all extravagance,