CHEMICAL BASIS OF THE ANIMAL BODY. 181 



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 



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



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



nitric acid and caustic soda so characteristic of the other xanthin 

 bases. It gives no green colouration with 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 entangled in the fibrin, since he finds that, by similar 

 treatment, isolated nuclein yields no inconsiderable amount of hypo- 

 xanthin 2 . The nuclein however from egg-yolk does not yield hypo- 

 xanthin, and thus resembles the nuclein derivable from casein 3 . 



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

 1878. Chittenden, JL of Physiol. Vol. n. (1879), p. 28. 



2 Zt.f. physiol. Chem. Bde. in. (1879), S. 284, iv. 290, v. 152, 267, vi. 423, 

 Of. Low, Pfliiger's Arch. Bd. xxn. (1880), S. 62. 



3 Kossel, Verhandl. d. physiol. Gesell., Arch. f. Physiol. 1885, S. 346/j%&' 



