COMPOSITION OF THE URINE. 



435 



a purin body. The intimate chemical relationship of these bodies 

 is indicated by the following structural formulae : 



HN CO N C NH 2 



II I 1 



C NH HC C N 



HC 



Hypoxanthin. 



N C 



Adenin 



(NH 2 )C 



HN CO 



C NH 



CH 



HN CO 



OC C NH 



H 



| || 

 N C 



CO 



NH 



Uric acid. 



Guanin. 



HN CO 

 OC C NH 

 HN C N 



Xanthin. 



" Purin, as has been shown by E. Fischer, has the formula : 

 N=CH 



HC C NH, 



II If 



N C N 



"The purin bases and uric acid are derived from purin by 

 simple substitution of the various hydrogen atoms by hydroxyl, 

 amid, or alkyl groups, as is plainly evident from comparison of 

 the different formulae. 



" Secondly, it must be noted that all true nucleins on decompo- 

 sition by chemical means yield more or less of the above purin 

 bases, as was first pointed out by Kossel. This means that all 

 nucleins contain in their molecules some purin bases i. e., in a 

 state of combination, from which combination they can be split 

 off by appropriate means either in the body or by chemical 

 methods outside of the body. Further, as these nuclein or purin 

 bases stand in such close relationship to cell-nuclei, it is easy to 

 see how the quantity of these substances may be largely increased 

 whenever from any cause the number of nucleated cells is increased 

 in any part of the body. Thus, while normal blood yields only 

 traces of purin bases, in leukemia the amount of nuclein bases 

 may be increased to over 0.1 per cent." 



