RELATION OF BLOOD TO URINE. 133 



so far altered in the organism that they combine with 

 oxygen, has a marked influence on the formation of 

 uric acid. The urine, after fat food has been taken, 

 is turbid, and deposits minute crystals of uric acid. 

 (PROUT.) The same thing is observed after the use 

 of wines in which the alkali necessary to retain the uric 

 acid in solution is wanting, but never from the use of 

 Rhenish wines, which contain so much tartar. 



In animals which drink much water, by means of 

 which the sparingly soluble uric acid is kept dissolved, 

 so that the inspired oxygen can act on it, no uric acid 

 is found in the urine, but only urea. In birds, which 

 seldom drink, uric acid predominates. 



If to 1 atom of uric acid we add 6 atoms of oxygen 

 and 4 atoms of water, it resolves itself into urea and 

 carbonic acid : 



1 at. uric acid C 10 N 4 H 4 O 6 1 



4 at. water > }>= J 2 ' urea C 4 N 4 H 8 O 4 , 



6 at. oxygen $ H 4 O 10 j t 6 at. carbonic acid C 6 Oi 2 



C 10 N 4 H 8 16 C 10 N 4 H 8 16 



33. The urine of the herbivora contains no uric acid, 

 but ammonia, urea, and hippuric or benzoic acid. By 

 the addition of 9 atoms of oxygen to the empirical for- 

 mula of their blood multiplied by 5, we obtain the ele- 

 ments of 6 at. of hippuric acid, 9 at. of urea, 3 at. of 

 choleic acid, 3 at. of water, and 3 at. of ammonia ; or, 

 if we suppose 45 atoms of oxygen to be added to the 

 blood during its metamorphosis, then we obtain 6 at. of 

 benzoic acid, 13| at. of urea, 3 at. of choleic acid, 15 

 at. of carbonic acid, and 12 at. of water. 



