THE -XlTROGENOtTS PllIXCIPLES OP URINE. 295 



of mine, suffers decomposition, and its elements, combin- 

 ing with the elements of water, are completely transformed 

 into carbonate of ammonia. 



Urea. Water. Carbonate of Ammonia. 



CO NJI, + 2H,0 = 2(NHJ, H,0,CO,. 



As we have learned from Way's experiments, clay is 

 able to i-emovefrom urine the "ferment" which occasions 

 its putrefaction. 



Urea is abundant in the urine of all carnivorous and 

 herbivorous mammals, and exists in small quantity in the 

 urine of carnivorous birds, but has not been detected in 

 that of herbivorous birds. 



Uric acid (CJI^N^Og)* is always present in healthy 

 human urine, but in very minute quantity. It is the chief 

 solid ingredient of the urine of birds and reptiles. Here 

 it exists mainly as urate of ammonia.** The urine of 

 birds and serpents is expelled from tiie intestine as a white, 

 thickish liquid, which dries to a chalk-like mass. From 

 this, uric acid may be obtained in the form of a white 

 powder, which, when magnified, is seen to consist of mi- 

 nute crystals. By powerful oxidizing agents uric acid is 

 converted into oxalate and carbonate of ammonia, and 

 urea. Peruvian guano, when of good quality, contains 

 some 10 per cent of urate of ammonia. 



Hippuric acid (C^H^NOJf is commonly abundant in 

 the urine of the ox, horse, and other herbivorous animals. 

 By boiling down fresh urine of the pastured or hay-fed 

 cow to ' 1^ its bulk, and adding hydrochloric acid, hippuric 

 acid crystallizes out on cooling in four-sided prisms, of- 

 ten two or three inches in lensrth. 



• Carbon 35.72 •♦ Carbon 32.43 t Carbon 60.74 



Hydrogen 2.38 Hydrogen 3.78 Hydrogen 4.96 



Nitrogen 33.33 Nitrogen 37.84 Nitrogen 7.88 



Oxygen 28.57 Oxygen 25.95 Oxygen ....26.48 



100.00 100.00 100.00 



