FOREWORD 



MAN has done but little through heredity to control or 

 vary human physical development, and while he dis- 

 cusses freely the problems of race betterment he resents 

 any effort at the application of methods for improvement. 

 Man has done much in support of the theory of evolution 

 by carefully considered and applied methods of develop- 

 ing the approved and desired characteristics of his 

 domestic animals whether for beauty, weight, strength, 

 speed or product. This has largely been accomplished 

 through the selection of the sire and the culling out of 

 the poorer females until standards for registry and for 

 advanced registry have been obtained; judges approve 

 as essential those modifications which are largely based 

 on the physical fitness of the individual. Inasmuch as 

 food by its oxidation in muscles or special glands main- 

 tains life and function, the perfect body is the body 

 which by its efficient lung surface and heart capacity 

 for circulation gives opportunity for oxidization of 

 an adequate intake of food. 



The great increase in the number of mental derelicts 

 and the increase of insanity is a subject of comment. 

 In the medical examination of millions of recruits for 

 the United States Army the wholesale application of 

 mental tests by experts in psychiatry placed the average 

 mental capacity surprisingly low. It is possible that 

 many mental breakdowns should be attributed to stress 

 of the mind which could be avoided by psychiatric tests 



