MUREXIDE. 1009 



alloxantin, more sulphur is deposited, and on saturating with 

 ammonia a salt crystallizes in thin colourless needles, of which 

 the formula is C 8 N 3 H 7 O 8 , which is considered a compound of a 

 new acid, dialuric acid, with ammonia. This acid is resolved 

 into new products when liberated by another acid, one of these 

 produced by exposure to air and evaporation of the solution of 

 the ammoniacal salt in dilute sulphuric or hydrochloric acid, is 

 dimorphous alloxantin, a body having the same composition as 

 alloxantin but a different form. On mingling boiling solutions 

 of sal ammoniac and alloxantin, the mixture becomes suddenly 

 of a purple red colour, then gradually loses its colour, becoming 

 turbid, and deposits colourless brilliant plates of uramile, which 

 become rose-red on drying. The liquid contains, after its de- 

 composition, alloxan and free hydrochloric acid. When a 

 solution of alloxantin is heated with caustic ammonia, uramile 

 and mycomelinate of ammonia are first formed, but are decom- 

 posed into other products by the prolonged action of ammonia 

 and air. A recent solution of alloxantin in ammonia gradually 

 absorbs oxygen from the air, and deposits crystals of oxalurate 

 of ammonia. 



MUREXIDE. 



% 



Formula: C 12 N 5 H 6 O 8 (Liebig and Wo3hler). This beautiful 

 product of the decomposition of uric acid was first described by 

 Dr. Prout, under the name of purpurate of ammonia. Murex- 

 ide may be formed by evaporating a solution of uric acid in 

 dilute nitric acid, until the solution acquires a flesh red colour, 

 allowing it to cool to 160, and then treating it with a dilute 

 solution of ammonia, till the presence of free ammonia is 

 remarked by the odour ; the liquid is then diluted with half its 

 volume of water and allowed to cool. It may also be formed by 

 bringing together many of the products of the action of nitric 

 acid on uric acid, with ammonia, with or without the presence 

 of atmospheric air. The following method, proposed by Liebig 

 and slightly modified by Gregory, appears to be the easiest and 

 most certain, and also most productive. 



" Seven grains of hydrated alloxan and 4 grains of alloxantin 

 are dissolved by boiling in 240 grains of water, and the boiling 

 solution added to 80 grains by measure of a cold and strong 



2 u u 



