52 ANIMAL ACIDS CONTAINING AZOTE. 



When dialurate of ammonia is moistened with dilute sulphuric 

 acid, that acid combines with the ammonia, and a matter scarcely 

 crystalline remains, which, when dissolved in water, disappears 

 altogether before it can be freed from sulphuric acid. The water 

 employed in washing it deposits, after an interval of some hours, 

 transparent and brilliant crystals of alloxantin. The liquor 

 freed from sulphuric acid by carbonate of barytes, and concen- 

 trated, gives a mother liquor, which, being mixed with nitric acid 

 and set aside for some hours, does not deposit nitrate of urea ; 

 but it concretes into transparent prisms similar to oxalic acid. 



Dialurate of ammonia dissolved in hot muriatic acid gives on 

 cooling a number of crystals similar to those of alloxantin, but 

 differing decidedly in their shape. The muriatic acid solution 

 contains urea. 



After having saturated a boiling solution of alloxane with sul- 

 phuretted hydrogen, and after ascertaining that the whole allox- 

 ane had been converted into the new product, the liquid was 

 concentrated in a retort out of the contact of air. On cooling 

 there was deposited a thick white opaque crust, having brilliant 

 facets. This crust became red when dried. It was very soluble 

 in cold water, had an acid reaction and taste, reduced oxide of 

 silver, gave with barytes a violet-coloured precipitate, and with 

 carbonate of ammonia, a little ammoniacal salt after an interval 

 of some time. 



When it is dissolved in boiling water or muriatic acid, the so- 

 lution, on cooling, deposits transparent crystals similar to allox- 

 antin. The mother liquor scarcely, if at all, reduces the salts of 

 silver. On the addition of ammonia and nitrate of silver, it 

 gives a white precipitate which, by the action of heat, becomes 

 dark-purple, without being reduced. This mother water gives 

 a white precipitate with barytes water. 



Wohler and Liebig distinguish, by the name of urile, the hy- 

 pothetical substance which they suppose to constitute uric acid, 

 when combined with urea : And it has been stated in a preced- 

 ing section of this chapter, that they consider the constitution of 

 urile to be C 8 Az 2 O 4 . Now 



If to one atom urile "... . C 8 Az 2 O 4 



We add four atoms water, . H 4 O 4 



We obtain an atom of dialuric acid, C 8 H 4 Az 2 O' 



