APP.] CHEMICAL BASIS OF THE ANIMAL BODY. 751 



to ordinary urea, but also, and at the same time, to the compound ureas 

 (ureides) spoken of above. Thus by oxidation with acids, 



Uric acid. Alloxan. Urea. 



C 5 H 4 N 4 3 + H 2 + O = C 4 N 2 H 2 O 4 + CT 2 H 4 O. 



Now alloxan, as was stated above, is a compound urea, viz. mesoxal yl- 

 urea, and by hydration can be converted into mesoxalic acid and urea, 



thus: 



Alloxan. Mesoxalic. Urea. 



C 4 N 2 H 2 4 + 2H 2 = C 2 H 2 O 6 + CN 2 H 4 O ; 



and by the action of chlorine uric acid can be split up directly into a 

 molecule of mesoxalic acid and two molecules of urea : 

 Uric acid. Mesoxalic acid. Urea. 



C 5 H 4 N 4 O 3 + C1 2 + 4H 2 O = C 3 H 2 O 5 + 2CN 2 H 4 OC + 2HC1. 

 By oxidation with alkalis, uric acid is converted into allantoin and 



carbonic acid, 



Uric acid. Allantoin. 



C 5 H 4 N 4 3 + H 2 + O = C 4 H 6 N 4 3 + CO 2 ; 

 and allantoin, by hydration, becomes allanturic or lantanuric acid and 



urea, 



Allantoin. Urea. Allanturic acid. 



C 4 H 6 N 4 O 3 + H 2 O - CH 4 N 2 + C 3 H 4 N 2 O. 



Now allanturic acid is a compound urea, with a residue of glyoxylic 

 acid. By other oxidations of uric acid, parabanic acid (oxalyl-urea), 

 oxaluric acid (which is hydrated parabanic acid), and dialuric acid 

 (tartronyl-urea) are obtained. In fact all these decompositions of a 

 molecule of uric acid lead to the production of urea and of a carbon acid 

 of some kind or other. The relation of uric acid to urea as illustrated 

 by the above reactions is brought very prominently into view by the 

 synthesis of uric acid which has recently been performed 1 . It is 

 obtained by simply fusing together glycocine (amido-acetic acid,) and 

 urea at a temperature of 200 230 C. The converse formation of gly- 

 cocine from uric acid with the simultaneous production of ammonia and 

 carbonic anhydride has been known for some time. Since in this latter 

 reaction the ammonia and carbonic anhydride are in the proportions in 

 which they would be obtained from cyanic or cyanuric acid, uric acid 

 has been regarded as built up from residues of cyanuric acid and glycin, 

 just as hippuric acid is formed from glycin and benzoic acid. It was 

 also at one time supposed that uric acid might be regarded as tartronyl 

 cyanamide. 



N 2 (ON), 



IH, 

 1 Horbaczewski, Ber. d. deutsch. chem. Gesell. Jahrg. 1882, S. 2678. 



