318 .VENTILATION 



energy. It is a term by which we express the entire process of 

 nutrition, both the building up and the nourishment of the liv- 

 ing cells and the production of energy. This whole process 

 of metabolism, however, is intimately connected with the con- 

 trol of bodily temperature. 



In the process of metabolism considerable quantities of 

 oxygen are consumed and considerable carbon dioxide and other 

 wastes are given off. This process of metabolism continues 

 as long as life exists. It is increased by exercise and work, and 

 is least when we are in a state of respose. Experimenters 

 generally calculate the amount of metabolism taking place by 

 determining the amount of carbon dioxide exhaled in a given 

 period of time. 



Now, it should be noted that metabolism still continues 

 even though we cease to take nourishment. In this case, 

 however, there is a consumption of the tissue of the body, and 

 a consequent decline in weight. We grow thin and poor when 

 we fast. These facts must be noted in order that we may un- 

 derstand what experimenters have done in the study of the 

 effects of external temperature upon metabolism. 



349. Effect of External Temperature upon Metabolism. In 

 studying the effect of external temperature upon metabolism, 

 experimenters have determined the amount of carbon dioxide 

 exhaled by a fasting man when in repose and in a room kept 

 at different temperatures for certain periods of time. Voit 

 gives the following table showing the number of grams of 

 carbon dioxide exhaled by such a fasting man during several 

 six-hour periods: 



Temperature of the room, Grams of carbon dioxid ex- 



i.e., external temperature haled during the six hours 



40F 211 grams of carbon dioxide 



45.5F 206 grams of carbon dioxide 



48F 193 grams of carbon dioxide 



58F 155 grams of carbon dioxide 



61F 158 grams of carbon dioxide 



75F 164 grams of carbon dioxide 



88F. 170 grams of carbon dioxide 



