ALLOXANTIN. 117 



alloxane, the liquid becomes muddy, and a precipitate of pure sul- 

 phur falls. Soon after a white crystalline powder is deposited, 

 and if the solution of alloxane was concentrated, the liquor as- 

 sumes the form of a thick magma of crystals of alloxantin. When 

 the precipitate is treated with boiling water it dissolves, with the 

 exception of the sulphur, and deposites a large quantity of allox- 

 antin in white transparent crystals. 



We convert alloxane into alloxantin also by adding to its solu- 

 tion a little muriatic acid, and then introducing a piece of zina 

 After an interval of some hours a considerable deposite of allox- 

 antin makes its appearance under the form of a crystalline crust. 



Protochloride of tin likewise throws down alloxantin from a 

 solution of alloxane. 



On the other hand, when alloxantin is treated by oxygenizing 

 bodies, it is converted into alloxane. If we add a few drops of nitric 

 acid to a solution of it, a slight effervescence is observed, and the 

 products of the decomposition of that acid are given out. When 

 the liquid is evaporated to the consistence of a syrup it congeals 

 into a crystalline mass, which, being dissolved in water, the 

 solution, when evaporated, spontaneously deposites colourless 

 crystals of alloxane. 



Alloxantin does not produce anything else than alloxane : no 

 ammonia nor any other substance is evolved. 



When ammonia is added to a hot solution of alloxantin it be- 

 comes purple ; but the colour disappears by the action of heat, 

 and also sometime after the hot solution is allowed to cool. When 

 ammonia is added to alloxane, scarcely a sensible change of co- 

 lour takes place. When we add nitric acid to alloxantin, drop 

 by drop, we observe, when we saturate a portion of it from time 

 to time with ammonia, and heat it a little, that the solution ac- 

 quires a more and more intense purple colour. After the addi- 

 tion of a certain quantity of nitric acid, and afterwards of am- 

 monia, the purple colour becomes so deep that the liquid loses 

 its transparency. But if more than a certain proportion of ni- 

 tric acid be added, this property disappears. 



A solution of uric acid in dilute nitric acid treated immediate- 

 ly by ammonia does not acquire a purple colour, or at least 

 speedily loses it again. The same solution subjected during some 

 minutes to boiling, or even gentle heat, takes with ammonia a 

 deep purple colour, and gives a considerable quantity of the 



