180 HYPOXANTHIN. 



5. Hypoxanthin or Sarkin. C 5 H 4 N 4 O. 

 NH CH 



CO C N:^ 



I I r<TT /9\ 



CM (i). 

 NH C = N 



Closely related to xanthin and usually occurring with it in the 

 tissues and fluids of the body. Its constitutional formula has not yet 

 been definitely ascertained, but it will probably be found to contain the 

 group N = CH N in the place of one urea residue in xanthin 1 . On 

 this supposition three formulae are obviously possible, and the correct 

 one has still to be determined. Hypoxanthin may be obtained from 

 normal muscles, and hence is found in larger amounts in 'extract of 

 meat.' It occurs also in the spleen, liver, and medulla of bones, and in 

 considerable quantity in the blood 2 and urine 3 of leukhsemic patients; 

 also in normal urine 4 and in vegetable tissues lupins 5 , malt-seedlings 

 and tea 6 . 



It is obtained from fluids or tissue extracts by means of the 

 processes already mentioned for the extraction of xanthin, and is 

 separated from the latter by taking advantage of the slighter 

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

 (sp. gr. 1*1). The crystalline form of this salt is characteristic. 



FIG. 26. HYPOXANTHIN-SILVER-NITRATE, C 5 H 4 N 4 . AgN0 3 . 

 (Krukenberg after Kiihne.) 



It also yields crystalline salts with nitric and hydrochloric acids. 

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



1 Fischer, Ber. d. d. chem. Gesell. 1882, S. 455. 



2 Kossel, Zt. f. physiol Chem. Bd. v. (1881), S. 267. 



3 Stadthagen, Virchow's Arch. Bd. cix. (1887), S. 390. 



4 Salomon, Ibid. Bd. n. (1878), S. 65, Bd. xi. (1887), S. 410. Salkowski, 

 Virchow's Arch. Bd. L. (1870), S. 195. 



5 Salomon, Verhand. d. physiol. Gesell. Nov. 12, 1880. Arch. f. Physiol. 1881, S. 

 166. 



6 Baginsky, Zt. f. physiol. Chem. Bd. vm. (18834), S. 395. 



