314 PRINCIPLES OF ANIMAL NUTRITION. 
were likewise made. Calculated per gram of nitrogen the results 
were as follows: 
Feed. Steer No. 1. | Steer No. 2. | Steer No. 3. 
Timothy hay and corn meal ........... 37.79 Cals.| 28.35 Cals. 
Cotton-seed feed.............000 eee eee 40.64 “ 134.25 “ |28.82 Cals. 
Timothy DAV 22.5. bcs Gath esha Rdoueye a'scaeee 19.29 “ |/18.01 “ |12.47 “ 
© andstarch.....0.....0.00% 25.02 <“ 
Wheat straw, corn meal, and linseed meal|11.24 “ |10.77 “ {10.95 “ 
The methods employed to prepare the urine for combustion 
were not altogether satisfactory, and the range of possible error 
is rather large. In but two cases, however, was the energy of the 
urine less than twice that corresponding to its nitrogen calculated 
as urea (5.434 Cals.), while in one case it reached over seven times 
that amount. Neither carbon nor hippuric acid having been deter- 
mined, no computations can be made as to the amount of non- 
nitrogenous matter present. 
Jordan * has reached similar results on the urine of cows, the 
average energy content per gram of nitrogen being as follows: 
Total Nitrogen, | Potential Energy,| Energy per Grm. 
Grms. Cals. Nitrogen, Cals. 
Cow No. 12 7 
Pé@riod) 15.307 aces ess 87.0 1658.3 19.06 
BOO Doc hye dahon Sse A 78.8 1547.2 19.63 
Beawaustasave ad 42.8 1323.5 30.93 
Cow No. 10.............. 65.5 1452.5 22.18 
As in the writer’s experiments, the energy per gram of nitrogen 
varies within wide limits, being greatest when the total nitrogen 
of the urine is least. In other words, it would appear that the 
non-nitrogenous ingredients of the urine of cattle are subject to 
less fluctuation than the nitrogenous ingredients. 
Kellner’s later experiments have fully confirmed his earlier 
results, as will appear in greater detail in subsequent paragraphs. 
He finds that the carbon rather than the nitrogen of the urine is 
the measure of its potential energy, and that an estimate of 10 
Cals. per gram of carbon gave for his experiments results closely 
approximating the truth.t 
* New York State Experiment Station, Bull. 197, p. 28. 
} Loc. cit., 58, 437. 
