240 MANURES. 



he explains by the decomposition of the water ; at the same time 

 are produced ammoniacal sahs, among which are acetates and lac- 

 tales, whose acids are generated by the very act of fermentation. 

 As a striking example of the agency of water in the transit of azote 

 into the ammoniacal state in a quarternary compound, we may tak*» 

 the putrefaction of urea. 



Urea is found in the urine of man and of quadrupeds ; its compo 

 sition, according* to M. Dumas, is : 



Carbon... 20.0 



Hydrogen 6.6 



Oxygen 26.7 



Azote .••46.7 



100.0 



The animal substances dissolved in urine, as the mucus of the 

 bladder, &c., undergo, on contact with the air, a modification which 

 causes them to act upon urea like ferments. By their influence the 

 elements of water react upon this substance, and transform it into 

 carbonate of ammonia. 



Carbonate of ammonia is composed of : 



Carbonic acid 56.41, containing j Sxy^g^en .'.'." .' !.*.*.*!!*.*!!.' .'.".'.4l!^ 



and 



Hydrogen 7. 



Ammonia 43.59, containing . j Azote 35.90 



But 100 of urea have been found to produce by fermentation 130 

 of carbonate of ammonia. 



Carbon. Hydrog^en. Oxygen, Aiote. 



Previous to fermentation, 100 of urea ) 20 00 6 60 2 67 46.7 



contains ....}' 



After fermentation, 130 of carbonate J 2000 10 00 533 46 7 



of ammonia contains . . J ' ' '_ '__ 



Difference 0.0 3.4 26.6 0.0 



So that during its transformation, the urea has gained 3.4 of hy 

 drogen, and 26.6 of oxygen. 



In water the hydrogen is to the oxygen as 1 to 8. (: : 1 : 8.) 



Now it is precisely in this proportion that hydrogen and oxygfti' 

 are found to be acquired by the urea in passing into the state of ea* 

 bonate of ammonia ; whence it follows that the elements of wave 

 are fixed in the process. 



The putrefaction of azotized substances is far from always pre- 

 senting results equally precise ; most frequently in decomposing 

 they pass through a series of changes, still very obscure, before 

 they attain their ultimate limit, viz. the production of ammoniacal 

 salts. Thus from putrefying caseum diffused in water, M. Braconnot 

 obtained, among other products and ammoniacal salts, a very remark- 

 able substance which he calls aposepedine. 



Aposepedine when purified is a white crystalline substance, soluble 

 in water and in alcohol, capable of combination with the metallic 

 oxides ; azote is one of its elements. 



This substance, although engendered by the act of putrefaction, is 

 rsvertheless itself capable of putrefying and giving birth to the last 

 products of the spontaneous decomposition of azotized matter. 



One of the most striking characteristics, at least that which is 



