ALLOXANTIN. 115 



turn, and a new yellow powder, scarcely soluble in water, is de- 

 posited. The same substance is often obtained when we trans- 

 form alloxane into alloxantine by zinc and muriatic acid, when 

 we employ too concentrated a solution, or continue the heat too 

 long. 



It is then deposited under the form of a yellow crust, which 

 may be purified by washing. It dissolves readily in ammonia, 

 and brilliant, yellow, granular crystals are soon deposited. When 

 heated with excess of ammonia they are transformed into a yel- 

 lowish jelly, very little soluble in water and ammonia. 



Wohler and Liebig dissolved in ammonia the yellow crystals 

 obtained by the action of zinc and muriatic acid on alloxane, and 

 neutralized the liquid by acetic acid. The yellow substance se- 

 parated in a few days. The analysis of it led to the formula C G 

 H 3 Az 2 3 =: 11-375. 



When a concentrated solution of pure alloxane is boiled, car- 

 bonic acid is given out for a long time. It then gives with 

 barytes a deep blue precipitate, and with carbonate of ammonia 

 a rich crystallization of murexide. On cooling, and even dur- 

 ing the boiling, a great quantity of alloxantin falls down, though 

 none originally existed in the liquid. 3 atoms of alloxane gave, 

 2 atoms alloxantin, . C 16 H 10 Az 4 O 10 



1 atom parabanic acid, . C 6 H 2 Az 2 O 6 



2 atoms carbonic acid, . C 2 O 4 



3 atoms of alloxane . C 24 H 12 Az 6 O 20 * 



SECTION V. OF ALLOXANTIN. 



The solution of uric acid in dilute nitric acid takes place with 

 the same phenomena as in concentrated acid. But after a gentle 

 evaporation the liquid deposites hard transparent crystals, which 

 are colourless, or have a slight yellow tinge. These crystals have 

 been distinguished by Wohler and Liebig by the name of allox- 

 antin. f 



Alloxantin is scarcely soluble in cold water. It dissolves, 

 though slowly, in boiling water, but is almost wholly deposited in 

 crystals as the solution cools. Even after five or six successive 

 crystallizations it reddens litmus- paper ; yet it wants the charac- 



* Ann. der Pharm. xxxviii. 357. 



f Ann. de Chim. et de Pliys. Ixviii. 227. 



