EXISTENCE OF UREA IN URIC ACID? 1 29 



of oxygen, so as to burn off two of its atoms of Irydrogen, and it 

 breaks up with the greatest ease, though without this additional 

 oxygen it has hitherto proved undecomposible. You 'will observe 

 from its formula, C 5 N 4 H 4 O 3 , that uric acid contains five atoms of 

 carbon and four atoms of nitrogen, while urea CN 2 H 4 0, contains 

 only one atom of carbon and two atoms of nitrogen. Accord- 

 ingly, we find that when dehydrogenised uric acid undergoes 

 complete decomposition by an absorption of water, it breaks up 

 into two molecules of urea (containing C 2 N 4 ) and one molecule 

 of a non-nitrogenous 3 -carbon acid. Whether, however, the re- 

 sidues of the two molecules of urea, obtainable by the oxidation 

 or dehydrogenation of uric acid, pre-exist in uric acid, the 

 3 -carbon acid alone being the dehydrogenised product, or whe- 

 ther the residue of the resulting 3~carbon acid pre-exists in uric 

 acid, the two atoms of urea being formed by dehydrogenation, 

 there is no evidence to show. The great stability of uric acid 

 under treatment with even strong acids and alkalies is certainly 

 opposed to its containing pre-formed residues of urea, since in all 

 undoubtedly so constituted bodies the residues of urea are re- 

 movable or decomposible with the greatest facility. On the 

 other hand, the assumption of pre-existent urea-residues in uric 

 acid very greatly facilitates our conception of its decompositions, 

 and, receiving the general consent of chemists, may, I think, be 

 provisionally admitted by us on the present occasion. 



(137.) Be this as it may, when uric acid is subjected to an 

 oxidising agent in presence of water, it gives up two of its atoms 

 of hydrogen to the oxidising agent, while the dehydrogenised 

 product reacts with water to form mesoxalic acid and urea. 

 Employing chlorine as the oxidising agent, we have the following 

 reaction, 



Chlorine Uric acid Water Mesoxalic Urea CMorhydric 



Cl a + C 5 N 4 H 4 3 + 4H a O C 3 H a 5 + aCN a H 4 + aHCl; 



or, supposing the reaction with water to take place after the 

 removal of the hydrogen by chlorine, 



