68 MAN, THE ANIMAL 



seem to be much to encourage man that his meta- 

 bolic efficiency will ever be higher. It is often 

 much below normal in cases of fatigue and indi- 

 gestion. Our problem is to keep it as nearly as 

 possible normal for us as individuals. We have 

 no knowledge of how much better off man would 

 be if he were twice as efficient metabolically. 

 What he could do under such conditions is pure 

 speculation. The stern fact that we must realize, 

 however, is that he must do his work under these 

 conditions which we have become accustomed to 

 speak of as normal and to think of as lOO per 

 cent, efficient. 



Thirdly, the mere fact that man has to eat in 

 order to secure adequate energy to keep his 

 living machine going has resulted in forcing 

 nature to devise methods of ridding the body of 

 all this unusable energy. So we have hundreds of 

 thousands of sweat glands and the lungs and kid- 

 neys devoted to keeping the living protoplasm free 

 from the poisonous effects of the accumulations of 

 energy that cannot be utilized within the body. 

 Herein lies the secret of much of human ills. The 

 wastes of metabolism are frequently not properly 

 removed from the body. Man is so constructed 

 that he cannot store these products within his body 

 as do butterflies, in part, where we find the scales 

 on their wings containing leidotic acid, a metabolic 

 waste product. 



