INFLUENCE OF MUSCULAR EXERTION UPON METABOLISM. 199 
corresponding increase in the urinary nitrogen (compare Chapter 
V), but this was small compared with the much greater amount of 
work performed. Moreover, it did not, as in the first series of 
experiments, augment from day to day during the period of severe 
work. The following table shows the principal results of this 
series, the figures for urinary nitrogen and for live weight being . 
given for the first and second halves of each period: 
Nitrogen. ¢ 
Period. peed Weight, 
Digested, In Urine, Kg. 
Grms. Grms. 
| eer ree errr cer s10,000 | 173.8 | Ger4 | Bee's 
Woe irarusatus chee, 2,430,000 | 178.8 { aes peta 
Tl aca arial Mees 810,000] 178.8 |} jog | 5433 
Series IV.—Upon the basis of the foregoing facts Kellner deter- 
mined the maximum amount of work which his horse could perform 
on a fixed medium ration without causing an increase in the proteid 
metabolism. One kilogram of starch was then added to the ration 
and the maximum amount of work that could be performed upon 
this new ration without causing such an increase was determined. 
In the nature of the case this determination could not be of the 
highest accuracy, but it is amply sufficient for our present purpose. 
The principal results are given in the following table, the amount 
of work being expressed by the number of revolutions of the dyna- 
mometer, since relative results are all that are required: 
Nitrogen. | i 
1 
Period. eS Weight, 
Digested, In Urine, Kg. 
Grms. Grms. 
| eee (| 300 |) 107.2 540 0 
Te au eae . 600 | | 110.2 
ica ee 600 |} 121.1 115.6 | 533.1 
1) en “a 500 109.4 | 582.5 
Te pe is 400 109.6 | 530.7 
s 
oD areas With 800 115.5 | 517.1 
Ti esaveca von t starch t 600 120.1 | 109.6 | 515.4 
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