The Source of Muscular Energy. 



65 



Here were two animals at rest, one getting much nitrogen in its 

 feed and the other a limited amount. Yfhile the work performed 

 by the pigs was equal, or very nearly so, for both were equally at 

 rest, the amount of nitrogen excreted in the urea varied greatly, 

 being in proportion to the amount of that element in the feed 

 given. 



93. Nitrogen excretion during hard labor. We next present a 

 case in which there was severe physical exertion, that we may 

 learn whether the nitrogen excreted bears a direct relation to 

 the work performed. In 1865, Professors Tick and Wislicenus 

 ascended the Faulhorn, an Alpine mountain. l In this laborious 

 effort they were careful to note their diet and to preserve all the 

 urine excreted during the trip, which was afterwards analyzed. 

 From before the ascent until after returning, the food consumed 

 contained only starch, fat and sugar. The following is a sum- 

 mary of the results so far as they relate to the point under con- 

 sideration: 



Nitrogen excreted in the urine by Fick and Wislicenus while ascending 



Mt. Faulhorn. 



"The record of the actual quantities is sufficient to show that 

 much less nitrogen was excreted by both experimenters during 

 and after than before the ascent. But the calculated amounts of 



1 Loc. cit. 

 5 



