New York Agricultural Experiment Station. 55 



observations by Kellner.* He found the average loss of methane 

 to be 4.2 grams per 100 grams of digested carbohydrates. As 

 1 gram of methane represents 13.246 Cal., this energy loss 

 equals 55.633 Cal. for each 100 grams of digested carbohydrates. 

 The data showing the loss of energy in the urine present some 

 interesting considerations. In the first place they add to the 

 evidence already secured by Rubner, Henneberg, Kuhn and 

 Kellnerf that the old methods of calculating urine energy on the 

 assumption that the nitrogen exists wholly as urea and that the 

 amount of nitrogen multiplied by 5.343 Cal. repesents all the 

 urine energy, is greatly in error. The figures which follow make 

 it clear that the heat value of the urine solids may be several 

 times that resulting from the old method of calculation. 



Actual Heat Value of Urine Compabed with Calculated Value. 



cow 12. Cow 10. 



It appears that the actual heat value of the urine solids was 

 from three to four times as large as the value calculated on the 

 basis of nitrogen as urea. This is explained by the fact that a 

 variety of solids exist in the urine, quite a percentage of which 

 are not nitrogenous. 



It is also evident from the succeeding figures that the heat 

 value of urine bears no constant relation to its nitrogen content. 



*Landw. Vers. Stat., 53:420. 



tSee Zcit. f. Biol, 21: 250. Nctte Bcitrage, &c., p. 119. 



Landio. Vers. Stat., 44:348, 404, 474, 529. 



Ibid., 47: 283, 308. 



Also Bui. 42, Pa. State College Expt. Sta., pp. 148-150. 



