22 THE HUMAN BODY. 



The carbohydrates also consist entirely of carbon, 

 hydrogen, and oxygen ; they belong to the same class of 

 substances as starch and sugar. The most important cax- 

 bohydrate in the body is glycogen, a sort of starch found 

 stored up in the liver and muscles. Glucose or grape 

 sugar also exists in the body ; and lactose or milk sugar 

 is found in milk. 



What elements do carbohydrates contain ? Name the most im- 

 portant found in the body ? Where is glycogen found ? Where 

 milk sugar ? 



