APP.] CHEMICAL BASIS OF THE ANIMAL BODY. 755 



separated from the latter by the action of dilute hydrochloric acid; this 

 separation depends on the different solubilities of the hydrochlorides of 

 the two bodies. For further information see Neubauer and Vogel 1 . 



Carnin . C 7 H 8 N 4 O 3 . 



Discovered by Weidel 2 in extract of meat, of which it constitutes 

 about one per cent. 



It crystallises in white masses composed of very small irregular 

 crystals; it is soluble with difficulty in cold, more easily soluble in hot 

 water, insoluble in alcohol and aether. Its aqueous solution is not 

 precipitated by normal lead acetate, but is by the basic acetate of this 

 metal. It unites with acids and salts forming crystalline compounds. 



Preparation. Is found in the precipitate caused in extract of meat 

 by basic acetate of lead 3 . 



This body possesses an interesting relation to hypoxanthin, into which it maybe 

 converted by the action either of nitric acid or, still better, of bromine. 



Guanin. C 5 H 5 lSr 5 0. 



First obtained from guano, but recently observed as occurring in 

 small quantities in the pancreas, liver and muscle extract. 



It is a white amorphous powder, insoluble in water, alcohol, aether 

 and ammonia. It unites with acids, alkalis and salts to form crystallis- 

 able compounds. 



Preparation. From guano by boiling successively with milk of 

 lime and caustic soda, precipitating with acetic acid, and purifying by 

 solution in hydrochloric acid and precipitation by ammonia. 



Guanin may, by the action of nitrous acid, be converted into xanthin. 

 By oxidation it can be made to yield principally guanidine and parabanic 

 acid, accompanied however by small quantities of urea, xanthin and 

 oxalic acid. Capranica has given several reactions characteristic of 

 this body 4 . 



Its separation from hypoxanthin and xanthin depends on its in- 

 solubility in water and behaviour with hydrochloric acid. 



Kynurenic acid. C 20 H ]4 1ST 2 O d + 2H 2 O. 



Found in the urine of dogs, and first described by Liebig 5 . When 

 pure it crystallises in brilliant white needles, insoluble in cold, soluble 

 in hot alcohol. The only salt of this body which crystallises well is 



1 Ham- Analyse, Ed. vm. (1881), S. 26. Also the literature quoted above on 

 hypoxanthin. 



2 Ann. d. Chem. v. Pliarm. Bd. 158, S. 365. 



3 See Weidel, op. cit. 4 Zeitsch.f. physiol. Chem. Bd. rv. (1880), S. 240. 

 5 Ann. d. Chem. u. Pharm. Bd. 86, S. 125, and Bd. 108, S. 354. 



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