212 MAKUAL OF OATTLE-FEEDING. 



riods miglit liavo been due to tins canse, but it was ob- 

 served tliat in passing from Period III. to Period IV., 

 and fx'om thib to Period Y., the amount of ureal nitroi^en 

 sank ai once to about tlie average for the rebpective periods. 



Tlius, in tlie last four days of Period HI. the average 

 daily excretion of nitrogen was 124.4 grammes, and in the 

 tirst four days of Period IV., 104.8 grammes. 



It is easily conceivable that, on passing from a period of 

 more to one of less work, fat should be again laid up in 

 the body and the protein consumption thus diminished, 

 but it is evident that such an effect would be gradual, and 

 we cannot imagine that it should cause any such sudden 

 change as that just mentioned. 



We are consequently shut up to the conclusion that, 

 under the conditions of these experiments, the protein 

 consumption was greater or less according as more or less 

 work was performed, and it would thus appear that while 

 a moderate amount of work, like that performed in Voifs 

 experiments, does not sensibly increase the protein con- 

 sumption in the body, long-continued exertion may, on 

 the contrary, have that effect. 



It is of interest to note, in this connection, some experi- 

 ments made in 1867 by T. li. Noyes,*^* then a student in 

 the Yale Medical School. 



II is experiments wore, in the main, confirmatory of 

 Volt's results, but in the case of one of the subjects, in 

 whom the nmscular exertion produced groat fatigue and 

 exhaustion, an increased excretion of urinary nitrogen was 

 obsei'ved as a result of work, and the author suggests as 

 possible that, while ordinary work does not increase the 

 destruction of protein, exertion sufficient to produce ex- 



* Am, Jour. Med. Soi , Oct , 18G7. 



