TEMPERATURE OF THE BODY. 77 



If you keep your mouth closed, your tongue does not 

 feel warm on a hot day, or cold when the air around you 

 is at a freezing temperature. The reason of this is that 

 in your body heat is being produced all the time, keep- 

 ing the internal parts warm. This heat is known as ani- 

 mal heat. 



12. The Temperature of the Body. So long as you are 

 in health, a thermometer placed in your mouth would 

 indicate almost exactly the same temperature every day 

 in the year. This is a very curious fact. A stone or a 

 frog is cold on a cold day and warm on a hot day; but, 

 except sometimes on the outside, your body is always 

 hot, and hot to very nearly the same degree; in health 

 never below 98 or above 101 of an ordinary Fahrenheit 

 thermometer. All animals, as birds and beasts, which, 

 like man, have a regular temperature of their own, are 

 known as "warm-blooded" animals. Any condition of 

 the body in which its organs are hotter than their proper 

 temperature, is known as a "fever." 



13. How the Body is kept from getting too Hot. Every- 

 thing that works, even two sticks rubbed across each 

 other, produces heat, though in many cases it is too slight 

 to be noticed. The organs of our bodies are no excep- 

 tion; and the more they work, the more heat they pro- 

 duce. If all this heat remained in the body, we should 

 soon be in a high fever. It is carried off in several ways. 



12. What does a thermometer placed in the mouth show ? How 

 does your body differ as to temperature from a stone or a frog ? 

 What is the healthy temperature of the interior of the human body ? 

 What is meant by " warm-blooded animals" ? What is fever? 



13. Where is heat produced in the body? When most? Why must 

 some of it be got rid of? How do the lungs help in keeping us from 

 becoming too warm ? The sweat-glands ? The blood flowing through 

 the skin ? 



