158 WALTER JOXES 



labor that lias been expended upon the purine metabolism. Both species 

 also fail to exhibit adenase, and exhibit giumase irregularly in the various 

 organs. (Wells and Ca Id well.) 



The gradation from man to ape to monkey in relation to adenase 

 is interesting. Hunter and Given* (b) found that injected adenine was 

 larijelv excreted unchanged in the urine of the monkey Cercopithecus, and 

 Hunter and Givens (a) were able to show adenase in slight activity in organ 

 extracts of a second monkey Cebus apella. With organ extracts of a third 

 monkey Macacus rhesus, Wells was able to obtain a striking demonstra- 

 tion of adenase. 



The distributions of the pnrine ferments in the organs of the rabbit 

 and guinea pig are coincident throughout. (Mitchell.) 



10. The purine metabolism of the rat is curious. Rohde and Jones 

 found that neither the individual organs nor the combined organs of the 

 rat exhibit xanthine oxidase in spite of the fact that they could show the 

 plentiful presence of uric acid in rat's urine. They also found that the 

 combined organs of the rat could not change hypoxanthine. This ap- 

 parent contradiction is not different from many similar cases, and could 

 be accounted for by assuming that in rats, uric acid is formed along a 

 path that does not involve xanthine-oxidase. But Ackroyd (b) found that 

 the injection of hypoxanthine causes an increase in the allantoine of rat's 

 urine. This was a most puzzling matter until the work of Benedict (6) 

 appeared. 



11. Benedict found that the Dalmatian coach hound excretes both 

 allantoine and uric acid, and that when the urine of the animal is acidi- 

 fied with hydrochloric acid, a crystalline deposit of uric acid is formed. 

 Careful analyses of the dog's urine were made for both allantoine and 

 uric acid, aver a long period of time, and then uric acid was injected sub- 

 cutaneously. This caused the expected rise in the allantoine but the in- 

 jected uric acid also appeared, and quantitatively. From these results 

 Benedict concludes that "uric acid and allantoine are interrelated in metab- 

 olism in other wavs than have heretofore been assumed." 



THE ENZYMATIC DECOMPOSITION OF COMBINED PURINS 



observations indicate that the organism treats combined purines 

 differently from free purines. The following two experiments go to the 

 root of the matter. 



I. When adenine is digested for several days with an aqueous extract 

 of dole's liver, the substance remains unaltered and can be recovered. 

 Dog's liver does not contain adenase. But when nucleic acid (yeast or 

 tliyrnus) is digested with an aqueous extract of dog's liver, hypoxanthine 

 is formed in an amount corresponding to the adenine group of the nucleic 

 acid used. This is very clear. Dog's liver can deaminize combine adenine, 



