58o THE POPULAR SCIENCE MONTHLY 



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 physi- 

 cians and surgeons. Sociologists dispute whether heredity or environ- 

 ment determines the qualities of the man. Many botanists and zo- 

 ologists 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 diction- 

 aries 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 environ- 

 ment. 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 character- 

 istics, inherent if you choose. Their behavior controls if it does not 

 constitute the behavior of the living thing. But this behavior de- 

 pends 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 pro- 

 tested that I was omitting many links between the plants of my ex- 

 periments and the less fortunate of the human race. While frankly 

 admitting this, a scientific man may still believe that he can con- 

 tribute 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 fac- 

 tors 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? 



