34 ORGANIC CONSTITUENTS. 



Bb may be distingviislied from the preceding compounds 

 by its indifference towards bichloride of mercury. 



Be is freely precipitated by the addition of sulphate of 

 copper, but the deposit which is of a brownish colom', readily 

 dissolves in an excess of the test. If just a sufficient quantity 

 of the solution of sulphate of copper to dissolve the precipitate 

 be added, and heat applied, a green precipitate forms, and the 

 supernatant fluid is likewise green. Alum, cautiously added, 

 throws down a brownish yellow flocculent precipitate, which 

 dissolves in an excess of the test. Infusion of galls, added in 

 small quantity scarcely produces any turbidity in a solution of 

 this constituent, but when added freelj^, a copious precipitate 

 is deposited, which disappears on the application of heat, but 

 returns as the solution cools. Be may be distinguished from 

 A«, and Ab, by its indifference towards bichloride of mercury ; 

 from B«, and Bb, by its behaviour with neutral acetate of lead, 

 and sulphate of copper. 



Ca is precipitable by protochloride of tin. This, to- 

 gether with the reactions it displays towards bichloride of 

 mercury and infusion of galls, and its solubility in anhydrous 

 alcohol, is sufficient to distinguish it from any of the preceding 

 constituents. 



The characteristics already mentioned are sufficient to 

 distinguish Cb. 



Constituents of the extract of flesh not precipitable by tannin. 



Ac is remarkable for its indifference towards reagents. 

 The only important tests have been already mentioned. 



Ad is freely precipitated by bichloride of platinum ; 

 moreover the precipitate throAvn down by basic acetate of lead 

 is increased by heat. 



Ae [zomidin) jdelds a very copious green or grajdsh 

 green deposit, on the addition of acetate of copper. This pre- 

 cipitate does not dissolve in an excess of the test, but dissolves 

 freely in acetic acid : on boiling this precipitate in caustic 

 potash it is rendered brown, while the supernatant fluid assumes 

 a faint purple red tint. Infusion of galls renders a solution of 

 zomidin slightly turbid, and after some hours a few flocculi are 

 deposited, possibly in consequence of the existence of some 

 impurity in the zomidin. 



