302 BACTERIAL POISONS. 



and even became less in amount than before the experiment ; 

 but, on the other hand, the amount of xanthine in the urine 

 was found to have been increased above the normal. This 

 shows that hypoxanthine in the body is oxidized probably 

 first to xanthine, then into uric acid. According to ROBERT 

 hypoxanthine is a true muscle stimulant. 



The fact that hypoxanthine is so widely distributed in 

 the organism, and in much larger quantities than was 

 formerly supposed, shows that it constitutes, together with 

 the closely related bodies creatine, xanthine, guanine, etc., 

 the normal antecedents of urea and uric acid. This view is 

 furthermore strengthened since hypoxanthine is especially 

 abundant in those organs which are most active in pro- 

 ducing metabolic changes in the body, viz., the liver and 

 spleen. 



It may be prepared from the urine, according to the 

 method given under paraxanthine (page 322) ; or from 

 extract of meat, or from glandular organs, such as the liver, 

 spleen, etc., by the process on page 285. Nuclein, on de- 

 composition with acids, yields about one per cent, of this 

 base. It can be determined with adenine indirectly by 

 SCHINDLER'S method (page 286) ; but better still directly 

 by BRUHN'S picrate method (see page 286). After the 

 adenine has been precipitated by sodium picrate, the deter- 

 mination of hypoxanthine in the filtrate is not difficult if 

 hydrochloric and other acids, the silver salts of which do 

 not quite dissolve in ammonia, are absent. The filtrate 

 from the adenine picrate is rendered slightly alkaline with 

 ammonia and precipitated with silver nitrate at the boiling- 

 point. The slightly yellow-colored precipitate is washed 

 with hot water till the wash-water is colorless ; then dried 

 at 120 for from two to three hours, when it has the com- 

 position 2C 5 H 2 Ag 2 N 4 O + H 2 O. It contains, however, traces 

 of picric acid and some adenine silver, and hence the quan- 

 tity of hypoxanthine calculated from the weight obtained is 

 higher than it really is. BRUHNS, as a correction, subtracts 

 3.0 mg. from the calculated quantity of hypoxanthine. 



A more convenient method than the preceding is to esti- 

 mate hypoxanthine as hypoxanthine silver picrate. The 



