INFLUENCE OF SURROUNDING TEMPERATURE ON METABOLISM 115 



The following experiment on a grown guinea pig fasting, is given as an 

 example of the rise in metabolism appearing with a higher body temperature : 



The influence of food on the metabolism at different external temperatures 

 is a matter of great interest. The following experiment of feeding a small 

 dog with different quantities of meat is one of the many published by Rubner 

 on this subject. 



External 



Calories per kg. and twenty-four hours. 



From this and other experiments of the same purport we learn that with 

 a sufficiently large supply of meat the metabolism becomes almost independent 

 of the external temperature (experiment with 320 g. meat), while with a 

 supply which is too low to furnish the calorific energy necessary even at a 

 high temperature, the effect of the external temperature is felt to the full 

 extent. This, in the judgment of the writer, shows that the ingestion of pro- 

 teid beyond a certain limit increases the metabolism both at a high and at a 

 low temperature. If the heat production obtained in this way alone is suffi- 

 cient to cover the requirements of the body even at a low temperature, a 

 fall in the temperature will have no power of itself to produce a further rise 

 of metabolism. But if the rise due to proteid is not sufficient, a fall in the 

 temperature will force the metabolism up, though to a less degree than when 

 no proteid had been fed. 



