332 CARNINE. [BOOK i. 



Artificial Salomon 1 , and Krause 2 who worked under his direc- 



proiuction of tion, have shewn that both hypoxanthine and xanthine 

 xanthinefrom are formed in small quantities during the digestion of 

 proteids. fibrin with trypsin and pepsin. Both bodies are like- 



wise formed when fibrin is digested at the temperature of the body 

 with weak hydrochloric acid. 



Carnine. C 7 H 8 N 4 3 + H 2 0. 



This base, discovered by Weidel 3 , has only hitherto been found in 

 Liebig's extract of meat, though doubtless it is a regular constituent 

 of muscle ; it constitutes about 1 p.c. of extract of meat. 



Prepara- Liebig's extract of meat is dissolved in 6 7 times 



tion * its volume of warm water, and cautiously precipitated 



with a strong solution of baryta water, great care being taken to avoid 

 an excess of the precipitant. The filtrate is treated with solution of 

 basic lead acetate, and the precipitate collected and boiled with 

 water; the compound of carnine and lead being comparatively soluble 

 in boiling water is extracted by repeatedly boiling the precipitate 

 with water. The warm solution is treated with sulphuretted hydro- 

 gen, and the precipitate of lead sulphide having been separated by 

 filtration the filtrate is concentrated and treated with solution of 

 silver nitrate which precipitates a flocculent silver compound 

 (C 7 H ? N 4 O 3 ) 2 . AgNO 3 mixed with some AgCl. The latter is separated 

 by digesting the precipitate in ammonia. The precipitate is then 

 suspended in water, subjected to the action of H 2 S, and the filtrate 

 being concentrated yields crude carnine, which is purified by re- 

 crystallizing and by the action of animal charcoal. 



Pro erties Carnine is very little soluble in cold, but easily and 



completely soluble in boiling water. It is insoluble in 



alcohol and ether. Its aqueous solution has a neutral reaction ; . it 



has a scarcely perceptible taste at first, but leaves a slight bitter 



after-taste. 



Chemical When a hot solution of carnine is treated with a 



relations. saturated aqueous solution of bromine, a slight evolution 



of gas takes place, the solution is decolorized, and on concentration 

 deposits crystals of the hydrobromate of hypoxanthine ; at the same 

 time bromide of ethyl is formed ; thus : 



C 7 H 8 N 4 3 + 2Br = C 6 H 4 N 4 O.HBi- -f CH 3 Br + CO,. 



Carnine. Bromine. Hypoxanthine- Bromide Carbonic 



hydrobromate. of ethyl. acid. 



1 Salomon, "Bildung von Xanthinkorpern aus Eiweiss durch Pankreasverdam 

 Ber. d. deutsch. chem. Ges. Vol. xi. p. 574. 



2 Krause, " Ueber Darstellung von Xanthinkorpern aus Eiweiss." Inaug. 

 Berlin, 1878. (Abstracted in Maly's Jahresbericht, Vol. vm. p. 80.) 



3 Weidel, "Carnin, eine neue .Basis aus dem Fleischextract." Ann. d. Chem. 

 Pharm. Vol. CLVIII. (1871) p. 353368. 



