These causes are sound as far as they go; but do not cover the whole ground.
The farmer may be muscle-bound and stooping from his labor; but that does not account for his dyspepsia or his rheumatism.
Then we allege poverty as covering all. Poverty does cover a good deal. But when we find even a half-fed savage better developed than a well paid cashier; and a poor peasant woman a more vigorous mother than the idle wife of a rich man, poverty is not enough.
Then we say ignorance explains it. But there are most learned professors who are ugly and asthmathic; there are even doctors who can boast no beauty and but moderate health; there are some of the petted children of the wealthy, upon whom every care is lavished from birth, and who still are ill to look at and worse to marry.
All these special causes are admitted, given their due share in lowering our standards, but there is another far more universal in its application and its effects. Let us look back on our little ancestors the beasts, and see what keeps them so true to type.
The type itself set by that balance of conditions and forces we call "natural selection." As the environment changes they must be adapted to it, if they cannot so adapt themselves they die. Those who live are, by living, proven capable of maintaining themselves. Every creature which has remained on earth, while so many less effective kinds died out, remains as a conqueror. The speed of the deer—the constant use of speed—is what keeps it alive and makes it healthy and beautiful. The varied activities of the life of a leopard are what have developed the sinuous gracile strength we so admire. It is what the creature does for its living, its daily life-long exercise which makes it what it is.
But there is another great natural force which works steadily to keep all animals up to the race standard; that is sexual selection. Throughout nature the male is the variant, as we have already noted. His energy finds vent not only in that profuse output of decorative appendages Ward defines as "masculine efflorescence" but in variations not decorative, not useful or desirable at all.
The female, on the other hand, varies much less, remaining nearer the race type; and her function is to select among these varying males the specimens most valuable to the race. In the intense masculine competition the victor must necessarily be stronger than his fellows; he is first proven equal to his environment by having lived to grow up, then more than equal to his fellows by overcoming them. This higher grade of selection also develops not only the characteristics necessary to make a living; but secondary ones, often of a purely aesthetic nature, which make much of what we call beauty. Between the two, all who live must be up to a certain grade, and those who become parents must be above it; a masterly arrangement surely!
Here is where, during the period of our human history, we in our newborn consciousness and imperfect knowledge, have grievously interfered with the laws of nature. The ancient proprietary family, treating the woman as a slave, keeping her a prisoner and subject to the will of her master, cut her off at once from the exercise of those activities which alone develop and maintain the race type.
Take the one simple quality of speed. We are a creature built for speed, a free swift graceful animal; and among savages this is still seen—the capacity for running, mile after mile, hour after hour. Running is as natural a gait for genus homo as for genus cervus. Now suppose among deer, the doe was prohibited from running; the stag continuing free on the mountain; the doe living in caves and pens, unequal to any exercise. The effect on the species would be, inevitably, to reduce its speed.