Respiration 



is withdrawn. The candle must have air in 

 order to burn. 



We will now consider the reason why air 

 is so absolutely necessary for the support of 

 life. Men and animals have a proper tempera- 

 ture — a heat which does not result from 

 exterior circumstances but from the mere 

 fact of life. Our clothes preserve it and 

 prevent it from dispersing, but they do not 

 impart it. Moreover, this natural heat re- 

 mains the same under a blazing sun or in 

 the frost of winter, in the warmest and in 

 the coldest climate ; it cannot be decreased 

 without risk to our lives. How is this bodily 

 heat preserved always and the same all over, 

 and how can it be produced except by com- 

 bustion ? As a matter of fact, permanent 

 combustion is constantly going on within us ; 

 respiration supplies it with air, and food with 

 fuel. To live is to be consumed in the 

 strictest sense of the word ; and to breathe 

 is to burn. There is an old figure of speech— 

 the torch of life. This figure expresses the 

 reality. Air consumes the torch, air con- 

 sumes the animal. It causes the torch to 

 diffuse heat and light ; it causes the animal to 

 produce heat and motion. Without air the 

 torch will be extinguished, and without air 



43 



