INFLUENCE OF MUSCULAR EXERTION UPON METABOLISM. 205 
day of the rest period and less than the average for the four pre- 
vious rest days. 
In the second experiment the work was continued for four days, 
then a rest day intervened, and then the work was continued for 
five more days. At the outset there was a slight increase of the 
proteid metabolism, but in the second period of five days it showed 
a marked decrease resulting in a progressive gain of nitrogen by 
the body, as is shown in the following tabular statement of the daily 
average results: 
External : ver: Nitrogen ‘ i 
Day. Work Nittosen N en of ene. ae of 
Done, Grms.’ of Feces, Grms. Nitrogen, 
Cals. Grms. Grms. 
0 25.11 1.89 23 .68 —0.46 
0 25.11 1.89 22.00 +1.22 
0 25.11 1.89 21.98 +1.24 
597 25.11 1.78 24.72 (2) —1.39 
467 25.11 1.78 23 .32 +0.01 
597 25.11 1.78 23 .23 +0.10 
596 25.11 1.78 21.83 +1.50 
0 25.11 1.78 22.06 +1.27 
595 25.11 1.78 20.82 +2.51 
De iccing aecwheisutiaare 590 25.11 1.78 19.64 +3.69 
TAT Osis har daeund 593 25.11 1.78 20.39 +2.94 
LO—Miewckveikes sp es 588 25.11 1.78 19.87 +3.46 
WIHT S 6. cee esa es 586 25.11 1.78 ; 19.79 +3.54 
This gain Caspari ascribes to an actual growth of the muscles as 
the effect of exercise, this growth according to him taking the form 
of a hypertrophy of the fibers. No determinations of the gain or 
loss of carbon were made. 
Bornstein,* who had previously investigated the possibility of 
increasing the store of proteids in the body by the addition of pro- 
teids to the food, has also contributed to the investigation of this 
phase of the question. His experiments were made upon himself. 
For seven days he consumed a uniform ration containing a moder- 
ate amount of protein and sufficient non-nitrogenous nutrients, 
according to previous experience, to maintain his body. The latter 
was in equilibrium with the food as regards nitrogen from the first 
day. Then the proteid supply was increased by approximately 
50 per cent. by the ingestion of pure proteids and light work (17,000 
* Arch. ges. Physiol., 83, 540. 
