46 FIRST PRINCIPLES. 



is composed chiefly of urea (CON 2 H 4 ) and hippuric acid 

 (C 6 H 5 CO. NHCHgCOOH). Z. Roussin suggests that 

 during work, the former is converted into the latter by the 

 increased action of the organs of breathing ; for at such 

 times the percentage of the hippuric acid is raised and that 

 of the urea diminished ; the converse being the case during 

 rest. The decomposition of both urea and hippuric acid is 

 effected by bacteria. 



The Urea (CON 2 H 4 ) breaks up under the influence of 

 the micrococcus urece, and uniting with a portion of the 

 water (H 2 O) becomes converted into ammonium carbonate 

 (NH 4 ) 2 CO 3 . Thus: 



CON 2 H 4 + 2H 2 = (NH 4 ) 2 C0 3 . 



The ammonium carbonate remains partly in solution, and 

 being volatile, partly escapes into the air. In both cases it 

 becomes decomposed into ammonia gas (NH 3 ), carbonic acid 

 gas, and water. Thus : 



(NHJ 2 C0 8 = 2NH. + H 2 + C0 2 . 



The hippuric acid is decomposed by bacteria probably as 

 follows : 



C 6 H 5 CO. NHCH 2 COOH + H 2 O = C 6 H 5 COOH + NH 2 CH a COOH. 

 (Hippuric acid ) (Water.) (Benzoic acid.) (Amido acetic acid.) 



The benzoic acid . would unite with the ammonia derived 

 from the urea, and would form ammonium benzoate ; and the 

 amido acetic acid, by the action of bacteria, would partly 

 break up into ammonia and acetic acid (CH 3 COOH) ; and 

 the acetic acid would become converted into ammonium 

 acetate. 



The principal products of tlie decomposition of iirine would 

 therefore be : Ammonium carbonate, ammonia, ammonium 

 benzoate, amido acetic acid, and a small quantity of 

 ammonium acetate. 



