BIOLOGY AND PROGRESS 213 



eries to mankind as a whole. It is of little value 

 for a few learned men to know these facts 

 and personally benefit through their application, 

 it is a wholesale application that is most needed. 

 The elementary understanding of the use of 

 energy by the human body should enable man to 

 understand easily why he cannot substitute "food" 

 lacking in energy for food that has been his 

 natural source of energy for thousands of years. 

 It is, therefore, not that so much more informa- 

 tion is needed about what makes the body go as 

 it is the sensible application of what is abundantly 

 testified to by every scientific investigation in meta- 

 bolism. 



Progress will also be made in finally grasping 

 the significance of vitamines. These are again 

 natural parts of natural foods. Their chemical 

 features are still unknown and man has yet to 

 discover their full value in his diet. When this 

 discovery is made, we shall realize the importance 

 of another limitation, similar to the chemical mes- 

 sengers, to which man has become adapted 

 through centuries of making up his dietary from 

 selected foods. 



The chemist will continue to make new com- 

 binations of atoms and molecules that will exceed 

 in complexity the more than two hundred thou- 

 sand compounds already made, some of which 

 even Nature has not produced. At any time he 



