AND OTHER URINARY DEPOSITS 149 



Nuclease, splitting nucleoprotein, and liberating 

 guanin and adenin. 



Guanase, converting guanin (CsHsN^Q-NH,) into 

 xanthin (QH,N,0,). 



Adenase, converting adenin (C5H3N/NH.,) into 

 hypoxanthin (CH^NP). 



Oxidase, converting xanthin (CH^N^OJ and hypo- 

 xanthin (C-H^NP) into uric acid (QH^N.Og). 



If spleen pulp, which is rich in nuclei, is left to 

 digest itself at a suitable temperature, xanthin and 

 uric acid are formed in situ. 



The purin bodies, then, spHt off from nucleoprotein 

 in the body or derived from food containing purin 

 bodies or nucleoprotein, are acted on in the spleen 

 and in all other organs by these ferments, and even- 

 tually uric acid would be produced. This is excreted 

 by the kidney as rapidly as it is formed, so that it 

 is not possible to isolate it from normal blood. 



Side by side with this, the liver is exercising its 

 destructive function on so much of the uric acid as 

 may be brought to it. The products of its action 

 are urea, and probably glycine (amino-acetic acid). 

 If the liver is largely shut out of the circulation by 

 means of Eck's fistula (putting the portal vein into 

 the inferior vena cava) , uric acid appears in the blood 

 even on a purin-free diet, because now so much of it 

 escapes the activity of the liver cells. The same 

 effect is observed if the aorta is tied above the coeliac 

 axis, both the liver and the kidney being shut off by 

 this operation. 



A little remains to be said with regard to the 

 endogenous origin of purin bodies. They are derived 



