Page:Popular Science Monthly Volume 74.djvu/584

Rh another shape or remain amorphous on some other planet where the force of gravitation, the composition and pressure of the atmosphere, and other factors of its environment, would be different from those constituting our environment on this earth.

Students of the natural sciences reckon with circumstance as well as substance. Physicists and chemists know this, and work with a conscious realization of this fact. Of the biologists, none more keenly realize the significance of circumstance to the organism than physicians and surgeons. Sociologists dispute whether heredity or environment determines the qualities of the man. Many botanists and zoologists meantime are discussing fine-spun theories of heredity based on the infinitely more finely spun microscopic structure of plant and animal cells, devising a scientific vocabulary which breeds dictionaries while it veils our real ignorance of the facts concerned.

The thorough study of mankind, or of any other living or lifeless thing, involves a study of the substance of the thing and of its environment. Study of the simple substance of blue-stone and of common salt is comparatively easy; but the bodies of living things contain and probably consist of many substances, few of which are as simple as blue-stone and common salt. Definite chemical compounds, many of them complex and unknown, constitute the bodies of living things. These compounds possess their own properties, their own characteristics, inherent if you choose. Their behavior controls if it does not constitute the behavior of the living thing. But this behavior depends on circumstance, is controlled by environment. The living thing, human or vegetable, can not be known till its environment as well as its substance, and the influence of the one upon the other, are known.

The chaplain of this university, coming to my laboratory one day, was surprised by some machinery which he saw there and asked its purpose. I told him that I was proving that, if you took a slum-child early enough, you could make a decent man of him. My friend protested that I was omitting many links between the plants of my experiments and the less fortunate of the human race. While frankly admitting this, a scientific man may still believe that he can contribute to such proof by using guinea-pigs, or rats, or even plants, as the objects of his experiments. These experiments are designed to furnish information about the circumstances, the influences, the factors of the environment, which affect behavior.

We see the various factors composing our environment directing the movements of our fellows. A bright light or an unusual sound at once attracts notice, may even draw a crowd. The absence of light, generation after generation, has cost cave animals their organs of vision. Who can say that the perpetual noise of our cities will not induce changes in the nervous balance, if not in the organs, of men?