MAKITAL OF CATTLE-FEEDING. 209 



must be oxidized to sulphxiric and phosplioric acids and 

 finally leave the body in the urine, since these acids cannot 

 assume the gaseous form at the temperature of the body. 

 In the above experiments the quantity of these acids wds 

 determined in the experiments made on an average die^, 

 and the following results obtained : 





Sulphuric *icid, 

 Gruib. 



Phosphoric aoid. 



Grxiis. 



Rest 



2.61 

 2 57 



4.19 



Work 



4.U 







The quantities in rest and work are identical within the 

 limits of error. 



Keliner's Experiments. — ^Almost all investigators who 

 liave experimented upon this subject have obtained results 

 agreeing in the main with those of Pettenkofer & Voit, 

 while most of those who have reached contrary conclusions 

 have used palpably imperfect methods of experiment. 



Some late researches by Kelluer '^' seem to indicate, how- 

 ever, that Pettenkofer & Yoit's experiments may not cover 

 the whole ground. In none of the experijnents hitherto 

 described was the work continued for any considerable 

 length of time. In Voit's experiments it was confined to 

 periods of ten mniutes each, and in those of Pettenkofer 

 & Voit it was continued only for a few days at most, and 

 under these circumstances caused no increase in the protein 

 consumption. 



Ivellner's experiments were made at the Tlohenheim 

 Experiment Station, on a horse. They included five 

 periods of from one to two weeks each, during each of 



*Laiidw. Jahibacher, VIII., 701. 



