190 OF MANURE. 



soil by supplying it with urine, we find that this 

 liquid contains in solution ammoniacal salts, uric 

 acid (a substance containing a large quantity of ni- 

 trogen), and salts of phosphoric acid. 



According to Berzelius 1000 parts of human urine 

 contain : — 



Urea . . . 3010 



Free Lactic acid,* Lactate of Ammonia, and animal 



matter not separable from them . . . 17.14 



Uric acid I'OO 



Mucus of the bladder 32 



Sulphate of Potash 3-71 



Sulphate of Soda 3-16 



Phosphate of Soda 2 94 



Phosphate of Ammonia 1*65 



Chloride of Sodium 4*45 



Muriate of Ammonia 1-50 



Phosphates of Magnesia and Lime ... J*00 



Siliceous earth 003 



Water 93300 



1000-00 



If we subtract from tly above the urea, lactate of 

 ammonia, free lactic acid, uric acid, the phosphate 

 and muriate of ammonia; 1 per cent, of solid matter 

 remains, consisting of inorganic salts, which must 

 possess the same action when brought on a field, 

 whether they are dissolved in water or in urine. 

 Hence the powerful influence of urine must depend 

 upon its other ingredients, namely, the urea and am- 

 moniacal salts. The urea in human urine exists 

 partly as lactate of urea, and partly in a free state. 

 (Henry.) Now when urine is allowed to putrefy 

 spontaneously, that is, to pass into that state in 

 which it is used as manure, all the urea in combina- 

 tion with lactic acid is converted into lactate of am- 

 monia, and that which was free, into volatile carbon- 

 ate of ammonia. 



In dung-reservoirs well constructed and protected 

 from evaporation, this carbonate of ammonia is re- 

 tained in the state of solution, and when the putre- 



* Lactic acid has been found in most animal fluids and in several 

 plants. It was first obtained from sour milk, heiice its name from the 

 Latin lac J milk. 



