372 CHEMISTRY OF THE LEUCOMAINS. 



decomposition one half of the hypoxanthin passes into solution, and 

 can be recovered on boiling with addition of silver nitrate in the 

 crystalline form ; or in the cold, as the usual amorphous precipitate, 

 C,H,Ag,Np.Hp. 



Hypoxanthin silver nitrate, CjH,N,O.AgNOj (Ag = 35.20 per 

 cent.), is the best known compound ; its formula was established by 

 Strecker. It is obtained by dissolving the above precipitate, pro- 

 duced by addition of silver nitrate to an ammoniacal solution of the 

 base, in hot nitric acid, specific gravity 1.1 ; on cooling the hypo- 

 xanthin silver nitrate crystallizes in the form of tufts of microscopic 

 needles or plates. Heated at 100°- 120° it remains constant in 

 weight ; the quantity of silver present, when determined, is always 

 somewhat higher than the theoretical, especially if an excess of silver 

 nitrate is employed in the precipitation. The explanation of this 

 fact is probably that given under adenin, though presence of silver 

 chlorid may partly^e the cause. On treatment with ammonia it 

 loses not only nitric acid, but also half of the hypoxanthin, and 

 CjH^Ag^N^O.SHjO forms. The change takes place readily even in 

 the cold, and if during the digestion an excess of silver nitrate is 

 added, the hypoxanthin set free is converted into this compound, 

 which is wholly constant in composition compared with the hypo- 

 xanthin silver nitrate. The conversion is quantitative. Very dilute 

 hydrochloric acid, as well as hydrogen sulphid, removes the silver 

 from this compound. 



Hypoxanthin • silver picrate, Q;^^A.gTSp.C^^(¥i0^pB. (Ag 

 = 22.88 per cent.), is gradually formed by adding silver nitrate to 

 a boiling solution of hypoxanthin picrate. The precipitate is granular 

 and of a lemon-yellow color, and consists of aggregations of fine, short 

 needles. It is slightly soluble in hot, insoluble in cold water. It 

 is, therefore, applicable for a quantitative determination of the base. 

 Aqueous ammonia very readily and completely removes the picric 

 acid from the compound, and the residue is hypoxanthin silver, 

 which is slightly colored yellow by a trace of picric acid ; half of 

 the hypoxanthin passes into solution. Nitric acid with difficulty 

 converts it into hypoxanthin silver nitrate. 



Hypoxanthin mercuric chlorid, CjHjN^OHgCl, is obtained by add- 

 ing an equivalent quantity of mercuric chlorid to a boiling solution 

 of hypoxanthin. The precipitate, which increases on cooling, is 

 crystalline. 



A second compound, CjHjN^OHgjClj , is produced by adding a 

 strong excess of mercuric chlorid, in the cold, to an aqueous solu- 

 tion of hypoxanthin. It forms a heavy granular micro-crystalline 

 precipitate, which contains some water of crystallization. 



By boiling the preceding compound with just sufficient hydro- 

 chloric acid to effect complete solution, there is formed on standing 

 a precipitate of white roundish aggregates of leafy or needle-shaped 



