180 



HYPOXANTHIN. 



solubility of its salt with nitrate of silver in boiling nitric .acid 

 (sp. gr. I'l). The crystalline form of this salt is characteristic. 



It also yields crystalline salts with nitric and hydrochloric 

 acids. 



Hypoxanthin is soluble in 300 parts of cold and 78 of boiling 

 water, insoluble in cold alcohol and in ether, soluble in 900 parts 

 of boiling alcohol. It does not yield either Weidel's reaction or 

 the reaction with nitric acid and caustic soda so characteristic of 

 the other xanthin bases. It gives no green colouration with 



FIG. 27. HYPOXANTHIN-NITRATE, C 5 H 4 N 4 . HN0 3 . (Kiihne.) 



FIG. 28. HYPOXANTHIN-HYDROCHLORIDE, C 5 H 4 N 4 . HC1. (Kiihue.) 



caustic soda and chloride of lime such as xanthin does (Hoppe- 

 Seyler's reaction), but after treatment with hydrochloric acid 

 and zinc, it yields a ruby-red colouration on the addition of an 

 excess of caustic soda (Kossel). In this reaction it resembles 

 adenin. 



During the putrefactive decomposition of proteids (fibrin) or 

 by the action of boiling water, dilute acids, or gastric and 

 pancreatic enzymes, hypoxanthin can be obtained in minute 

 amounts. 1 This was at first regarded as evidencing a direct 

 formation of xanthin bases from proteids. The researches of 

 Kossel have however shown that the source of the hypoxanthin 

 in the above cases is probably the nuclein of the corpuscles en- 

 tangled in the fibrin, since he finds that, by similar treatment, 



1 Salomon, Ber. d. d. chem. Gesell. 1878, S. 574. Krause, Inauq.-Diss. Berlin, 

 1878. Chittenden, .//. of Physwl. Vol. n. (1879), p. 28. 



