WORK 1 1 1 



out some increase in the catabolism of protein as an accompaniment 

 Pfliiger (329) admitted later that non-nitrogenous food might play 

 some part in contributing energy for muscle work, although the 

 nitrogen-containing material played the really important part. 



Noel Paton and others (323) found that, after moderate work, the 

 rise in the output of nitrogen was small, but after excessive work, 

 there was a marked rise in the nitrogen excretion. This marked rise 

 might have been due to the complete utilization of the non-nitrogenous 

 food material bringing about the breakdown of protein. Krummacher 

 (232) found that there was an increase in the output of nitrogen in a 

 man doing measured work, arid that the increased output took place 

 even when a very large amount of protein was ingested. Further, he 

 showed that the possible energy, calculated from the nitrogen excreted, 

 did not equal the energy expended in the work. Frentzel (139) like- 

 wise demonstrated that, even if the total nitrogen excreted on the day 

 of work, and not only the excess of nitrogen excreted, were regarded 

 as coming from protein utilized during work, the material utilized 

 would not be sufficient to furnish the energy expended. In one 

 experiment the amount of nitrogen excreted accounted for only 

 about two-thirds of the energy expended. Zuntz and Schumburg 

 (429) found in marching that the increase in nitrogen excretion took 

 place two or three days after the work. They also noted that other 

 factors besides the actual work influenced this output of nitrogen 

 that the amount of work, and the degree of protein catabolism, did 

 not run exactly parallel. Thus a much greater excretion of nitrogen 

 followed a march with a light load on a warm day than with a full 

 load and a normal temperature. Caspari (86) alternately rested and 

 worked dogs in nitrogenous equilibrium and found a slight increase 

 in the nitrogen output after work. Even this small rise he was in- 

 clined to ascribe to faulty dietetic conditions not to the supply of 

 the food being insufficient to cover the energy expended. 



Shaffer (369) carried out a series of experiments in which the effect 

 of increased and decreased muscular activity was tested, and found that, 

 with a sufficient supply of food, work had no effect on catabolism, as 

 indicated by the nitrogen and sulphur excretion in the urine. The 

 creatinine output was also quite unaffected, although it is generally held 

 that there is some close relationship between the creatinine output 

 and the amount of active muscular tissue in the body. I found that 

 there was a distinct increase in the output of nitrogen, when the sub- 

 ject was made to do hard work on an abundant, but nitrogen-poor diet. 

 Garratt (150) found that as the result of exercise there was a slight 



