300 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



These new secrets of the laboratory have resulted in greatly alter- 

 ing our concepts of many aspects of our individual and communal 

 life. Here are a few : 



1. Geneticists are no longer interested in the old debate as to 

 whether environment is more important than heredity. From their 

 point of view, both are of tremendous significance. What the or- 

 ganism inherits is not so much characteristics as the tendency to 

 produce these characteristics provided the environment is favorable — 

 a profound new discovery which, if it could be grasped by political 

 leaders in all its implications, might well make over our society. 

 For example, there is a species of rabbit whose hair is mostly white ; 

 but if exposed long enough to low temperature, black hair grows 

 out. Pink-flowered hydrangeas can be changed to blue by adding 

 iron salts to the soil. Tall corn planted too close together will 

 grow only a quarter of its normal size. Yet the offspring of these 

 rabbits, hydrangeas, and corn, in a normal environment, will again 

 have white fur, pink flowers, and tall stalks. When the hereditary 

 influences are strong, those of environment are correspondingly weak, 

 and vice versa. 



These changes, however, could not have taken place unless the or- 

 ganisms carried the special genes that make them possible. Not 

 all rabbits have fur that changes color; there are "Tom Thumb" 

 breeds of corn that never grow tall no matter how widely the hills 

 are spaced; some flowers remain the same color when fed iron salts. 

 In other words, environment can change you, but only on a basis 

 of what you originally possess — or lack. It is like the developing 

 chemical in the photographer's dark room; it creates nothing, but 

 it can bring out what is on the plate. The tragedy of life is that 

 we so often discard the plate without ever finding the perhaps rich 

 and beautiful picture concealed on it. 



2. For practical purposes, at least, we may assume that almost 

 nothing in our biological heritage is transmitted from one generation 

 to the next except what is passed on in the genes. This does away at 

 one stroke with a multitude of conceptions of the popular mind. It 

 is nonsense to suppose, for example, that because a mother before the 

 birth of her child receives a fright or sees a snake, the child will be 

 "marked," any more than he will be musical or artistic if she goes to 

 concerts and galleries. 



3. There is a popular theory that whole families can be subjected 

 to continuous decay and degeneration. This might be true under 

 very special circumstances, if, for instance, all the good men in a 

 community had been killed off in war, or in the case of isolated 

 groups where inbreeding would serve to reinforce undesirable strains 

 instead of desirable ones. The chances are, however, that when a 



