xi FOODS IN THE TISSUES 145 



has an abundant blood supply. The spleen is small dur- 

 ing digestion, but grows larger a few hours after meals, 

 reaching its greatest size about the fifth hour, and then it 

 slowly diminishes to its usual size. It is always small in 

 starved animals. This organ has been 

 carefully studied by scientists, but they 

 cannot say as yet what functions it 

 performs. It is thought by some that 

 it aids the liver in changing certain 

 ammonia compounds, that it manufac- 

 tures white corpuscles, and that it helps FlGt 75 ._ The spleen, 

 to destroy the worn-out red corpuscles. front view ( Zu PP ke )- 

 The spleen has been entirely removed in cases of disease 

 without causing any serious injury. It may be that other 

 organs carry on its functions when the spleen is removed. 

 110. Animal Heat. The oxidation of foods in the cells 

 gives rise not only to these harmful waste products but 

 also to a large amount of heat. We know the fire in a 

 furnace or stove will go out when the fuel is consumed. 

 If we wish to have it burn at a uniform rate fuel must 

 be added from time to time. The temperature of the 

 human body is kept at about 98^ F. in health. Even a 

 very slight variation from the normal temperature is 

 accompanied by either a fever or a chill. In man a 

 temperature of 102 F. means that combustion is too 

 rapid, and something should be done to restore it to the 

 normal. During periods of starvation or great prostra- 

 tion, and in certain diseases, the temperature may fall 

 several degrees below the normal. A temperature of 

 92 F. usually proves fatal. 



