Chemical Constituents of the Animal Body. 255 



The following are the formulae of the purine bases 

 which have been obtained by the hydrolysis of nucleic 

 acids : 



HN CO 



I I 

 OC C NH 



HN-CO 



I I 

 HC C NH 



>CH 



HN CO 



I I 

 NH 2 C C NH 



CH \CH 



HN C N 



Xanthine. 



N C N 

 Hypoxanthenine. 



N = CNH 2 

 C NH 



f_C N 

 Guanine. 



HC 



V 



CH 



N C N 

 Adenine. 



The pyrimidine bases contain only one ring, which has the 

 same relative arrangement of the carbon and nitrogen 

 atoms as exists in the six-membered ring of purine. These 

 have been synthesized chiefly by E. Fischer and his 

 collaborators, and by Wheeler and Johnson. The formulae 

 assigned to them by reason of these syntheses are the 

 following : 



HN CO N = CNH a HN CO 



OC CCH 3 OC CH OC CH 



I II I II I II 



HN CH HN CH HN CH 



Thy mine. Cytosine. Uracil. 



The relationship of the alloxuric bases to uric acid will be 

 evident from the above formulae, and has given rise to a 

 large number of researches bearing on the metabolism of 

 nucleic acid and the pathology of gout. 



