138 ANIMAL CHEMISTRY-f-LECTURE VI. ' 



subsequently discovered by Strecker in juice of flesh, and thought 

 to be a distinct base, has since proved to be identical. From the 

 results of Scheerer, Strecker, Gorup-Besanez, and others, it ap- 

 pears that hypoxanthine exists to a very appreciable extent in 

 most glandular juices and in muscular tissue, particularly of the 

 heart, while it has also been recognised in brain-substance and in 

 the blood and urine. It occurs as a white crystalline powder, 

 insoluble in cold and sparingly soluble in hot water. Strecker 

 has shown that by oxidation with nitric acid, it yields xanthine, 

 and gives accordingly with nitric acid, the characteristic reac- 

 tion of xanthine a compound which has also been detected in 

 blood and in most animal juices. Under the name of xanthic 

 oxide, it was discovered in 1819 by the elder Marcet, in a variety 

 of urinary calculus which subsequent experience has proved to 

 be very rare. It has been met with, more frequently indeed, 

 though still very seldom, as an amorphous urinary deposit, and 

 in one case recorded by Bence Jones it occurred in lozenge- 

 shaped crystals. Its habitual presence, however, in small quan- 

 tity, as a dissolved constituent of urine, seems now to be very well 

 established. Xanthine, moreover, is not only known as a urinary, 

 but also as an intestinal concretion, for Gobel has met with it as 

 the chief constituent of certain oriental bezoar stones obtained 

 from ruminating animals. I have already mentioned Strecker's 

 artificial production of xanthine by the oxidation of hypoxanthine 

 or sarcine with nitric acid. Conversely, Strecker and Rheineck 

 have very recently shown that uric acid, by deoxidation with 

 sodium-amalgam, yields a mixture of xanthine and hypoxanthine, 

 the latter in greatest proportion, so that the actual relationship of 

 the three bodies is now placed beyond all question. Hitherto 

 hypoxanthine and xanthine, having been obtained in small quan- 

 tities only, have not been subjected to any detailed examination. 

 It can scarcely be doubted, however, that xanthine is a mon- 

 ureide of barbituric and a di-ureide of malonic acid, in the same 

 sense that uric acid is a mon-ureide of dialuric and a di-ureide of 

 tartronic acid. We may hope, indeed, to have these relations 

 very soon established by experiment ; for, even if it should not 



