103 ]VIAN"UAL OF CATTLE-B^EEDI^NTG. 



peculiar arrangement of the respiration apparatus, claim to 

 have shown an exhalation of free gaseous nitrogen by 

 various animals; hut the method adopted by them de- 

 mands such extraordinarily accurate analyses that the 

 results obtained can as well be attributed to analytical 

 errors as to an actual excretion of free nitrogen. 



Determination of Gain or Loss of Flesh. — In the 

 foregoing paragraphs we have presented, somewhat at 

 length, some of the evidence which shows that nitrogen 

 is excreted to any considerable extent only in the vibible 

 ejecta. This evidence could have been greatly aniplilied 

 were it necessary, but enough has been given to prove the 

 point in question. 



% 



The value of this knowledge lies in the fact that by 

 virtue of it we can determine easily and exactly whether 

 an animal is gaining or losing nitrogenous constituents, 

 Le,^ flesh. "We need only to compare the amount of nitro- 

 gen in the digested portion of the daily fodder of the ani- 

 mal with that daily excreted in its urine ; or, more simply 

 still, to compare the total amount of nitrogen in the fodder 

 with that of all the sensible excrements, both urine and 

 dung. If the amount in the fodder is the greater, the 

 difference evidently must be still retained in the body as 

 flesh. If, on the contrary, the amount is greater in the 

 excrements, it shows as conclusively that more albuminoids 

 have been decomposed than have been supplied, and that 

 the animal is losing flesh. 



Furthermore, since the albuminoids contain on an aver- 

 age 16 per cent, of nitrogen, we can, by multiplying the 

 difference found by the factor 6.26, as explauied on page 

 17, calculate the weight of albuminoids corresponding to 

 the observed difference of nitrogen, and thus tell exactly 

 how much flesh has been gained or lost. If the amount 



