THE FOOD AS A SOURCE OF ENERGY. 313 
Ox A. : Ox B. 
Total nitrogen .............. 61.28 grams. 46.63 grams. 
“© earbon ......... elaaens 203.20“ 161.30“ 
Hippuric acid ............... 145.00" 126.40 “ 
Total energy ..............., 1945.00 Cals 1549.40 Cals. 
Assuming all the nitrogen not contained in the hippuric acid to 
have been in the form of urea, we have the following as the distri- 
bution of the carbon-and of the energy of the urine: 
Ox A. Ox B. 
Amount. Per Cent. Amount. Per Cent 
Carbon : Grms. . Gros. 
In hippuric acid ....... 87.48 43.05 76.26 47.28 
OY MITC By ios oe eee evita © 21.40 10.53 15.75 9.76 
‘“« other compounds... . 94.32 46.42 69.29 42.96 
Total g2ncnes cose 203.20 100.00 161.30 100.00 
Energy ‘ Cals. Cals. 
In hippuric acid ....... 821.30 42.23 715.90 46.20 
£6 UTCS oa cee ueececes 271.40 13.95 199.60 12.88 
“ other compounds. ... 852.30 43.82 633.90 40.92 
Potale 2scaceecasecns 1945.00 100.00 1549.40 100.00 
While the assumption that all the nitrogen was present either 
as hippuric acid or urea is not strictly correct. still the figures suffice 
to’show, first, that. a considerable proportion of the energy of the 
proteids of the food may be removed in the hippuric acid, and 
second, that the urine contains relatively considerable amounts of 
non-nitrogenous organic matter. Had the energy of the urine 
been computed from its nitrogen reckoned simply as urea the 
results would have been as follows: 
| Ox A. | Ox B. 
Calculated from N aS UTeS... 2... ee ee 331.6 Cals 252.3 Cals 
Actually present.........--.0-22222006- 1945.0 “ 1549.4 “ 
In experiments by the writer on the maintenance ration of 
cattle,* determinations of the total energy of the urine of steers 
* Penna. Experiment Station, Bull 42, p. 150. 
