FACTS AND FACTORS OF DEVELOPMENT 5 



is no mere logical inference from the doc- 

 trine of evolution, but a fact which has been 

 established by countless observations and ex- 

 periments. The essential oneness of all life 

 gives a direct human interest to all living 

 things. If "the proper study of mankind is 

 man," the proper study of man is the lower 

 organisms in which life processes are reduced 

 to their simplest terms, and where alone they 

 may be subjected to conditions of rigid ex- 

 perimentation. Upon this fundamental like- 

 ness in the life processes of man and other 

 animals are based the wonderful advances in 

 experimental medicine, which may be counted 

 among the greatest of all the achievements of 

 science. 



The experimental study of heredity, develop- 

 ment and evolution in forms of life below man 

 must certainly increase our knowledge of and 

 our control over these processes in the human 

 race. If human heredity, development and 

 evolution may be controlled to even a slight 

 extent, we may expect that sooner or later the 

 human race will be changed for the better. At 

 least no other scheme of social betterment and 



