COMPOSITION OF ANIMAL MANURES. 177 



maximum., were we to consider it as equal to one- 

 half per cent. It is certain, however, that these 

 excrements are not entirely free from nitrogen, for 

 they emit ammonia when digested with caustic 

 potash. 



The excrements of a cow, on combustion with 

 oxide of copper, yielded a gas which contained one 

 vol. of nitrogen gas, and 26*30 vol. of carbonic 

 acid. 



100 parts of fresh excrements contained 



Nitrogen . . . 0'506 



Carbon . . . 6-204 



Hydrogen . . . 0'824 



Oxygen . . .4-818 



Ashes . . . 1-748 



Water . . . 85-900 



100-000 



Now, according to the analysis of Boussingault, 

 which merits the greatest confidence, hay contains 

 one per cent, of nitrogen ; consequently in the 25 

 Ibs. of hay which a cow consumes daily, \ of a Ib. 

 of nitrogen must have been assimilated. This 

 quantity of nitrogen entering into the composition 

 of muscular fibre would yield 8*3 Ibs. of flesh in its 

 natural condition*. The daily increase in size of a 

 cow is, however, much less than this quantity. 

 We find that the nitrogen, apparently deficient, 

 is actually contained in the milk and urine of the 



* 100 Ibs of flesh contain on an average 15-86 of muscular fibre : 18 

 parts of nitrogen are contained in 100 parts of the latter. 



N 



