6o MAN, THE ANIMAL 



When these foods are taken into the digestive 

 tract, they have to undergo a definite series of di- 

 gestive changes before they can be absorbed into 

 the blood. These take place first in the mouth of 

 man, where the saliva helps to change the starches 

 into sugars — a change which is chemical in char- 

 acter. In the stomach, the proteins are partly 

 transformed and all three are fully digested after 

 they reach the small intestine. 



The conditions under which these changes take 

 place are fairly well understood. All of them can 

 be and have been duplicated many times in test 

 tubes in the laboratory. No one has ever seen 

 any explosions result from unsuitable combina- 

 tions of the various foods nor will there ever be 

 any, notwithstanding that they are said to be of 

 common occurrence, if one may believe the adver- 

 tisements of some of the new food faddists. After 

 the food has undergone the same kind of chemical 

 re-arrangement that it has been undergoing ever 

 since there was a human stomach and undergoing 

 the same re-arrangements that it will have to un- 

 dergo in the digestive canals of men in the future, 

 it is absorbed and passes into the blood. 



As the blood courses through the body, it finally 

 enters into the capillaries and is collected by the 

 veins to be returned to the heart. It now passes 

 to the lungs where a fresh supply of oxygen is 

 secured and some waste products are given off, 



