NON-NITKOGENOUS CARBON COMPOUNDS 27 



proportion in whicii they occur in water, namely, two 

 parts of hydrogen to one of oxygen. Carbohydrates fall 

 into two main divisions, the sugars and the starches. 

 The most important of the sugars is glucose or grape 

 sugar, found in the blood and in many other parts of the 

 body. Starch occurs in the body in a form called glyco- 

 gen, which is stored in the liver. When a carbohydrate 

 is oxidized it liberates much heat, and the oxidation in 

 the body of these compounds finrnishes us much of our 

 warmth. 



Fat. — This substance is present in the body in varying 

 amounts. Like the carbohydrates it is a compound of 

 carbon, hydrogen, and oxygen, and like them it produces 

 heat when oxidized and thus acts as a body fuel. It 

 occurs largely in a liquid state in the living body, in the 

 muscles, the blood, the bones, and connective tissues. 



We shall consider the properties of these carbon com- 

 pounds further, in our study of foods. 



