Davy — On some New Organic Nifroprussides. 321 



Quinidine mid CincJionidine Nitropriissides. 



Quinidine and cinchonidine, two bases which are isorQeric or of 

 the same percentage composition with quinine and cinchonine (and are 

 obtained from quinidine — a resinous matter produced in the prepara- 

 tion of quinine), form, with nitroprussic acid, as might be expected, 

 neutral and acid salts corresponding with those of quinine and cincho- 

 nine. The quinidine neutral salt is thrown down from the first in 

 great part as a crystalline precipitate, when a solution of the neutral 

 sulphate of that base is treated with one of sodium nitroprusside. Its 

 crystals are prismatic, and of a very light brown colour. This salt 

 requires about 105 times its weight of cold, and about 50 times of 

 boiling, water for its solution ; and it is readily soluble in rectified 

 spirits. Its solutions are neutral, and there can be no doubt that its 

 composition is similar to the quinine neutral salt where two molecules 

 of the base are united with one of the acid. 



The cinchonidine neutral salt, which is obtained by the same 

 means from the neutral sulphate of that base, is precipitated in the 

 form of minute oil-like globules, which on subsiding adhere together, 

 forming a sticky, more or less transparent, brown deposit, which exhi- 

 bits no disposition to crystallise even after standing for a considerable 

 time. This, on exposure to the air, hardens, becoming at the same 

 time very brittle and resinous in its appearance. This nitroprusside 

 requires about 217 times its weight of cold, and about 21 times of 

 boiling, water for its solution, and it dissolves readily in rectified 

 spirit. This salt being neutral in its reaction, there can be no doubt 

 that its constitution is similar to the corresponding cinchonine salt, 

 where two molecules of the base are combined with one of the acid. 

 The apparent absence of any disposition on the part of this nitroprus- 

 side to assume a crystalline condition, affords a distinctive character 

 between this and the corresponding cinchonine salt ; for though the lat- 

 ter is precipitated at first like the former, in minute oil-like globules, 

 and forms an apparently similar sticky, transparent, brownish deposit, 

 still, on standing for a variable period of some hours, it becomes highly 

 crystalline, furnishing very characteristic crystals, as already stated, 

 some of which may sometimes be seen fioating on the surface of the 

 supernatant liquid, or adhering to the sides of the vessel in which it is 

 contained. This salt, as well as the neutral quinidine nitroprusside, 

 dissolves readily in nitroprussic acid, and they both thus form crystal- 

 lizable acid salts similar to those in the case of quinine and cinchonine; 

 but therr further properties I have not yet been able to determine. 



Verafrine Nitroprusside. 



Veratrine, the active principle of the white hellebore, which is a 

 very powerful poison, forms with nitroprussic acid a neutral salt, 

 which may be readily obtained by precipitating its sulphate with 

 sodium nitroprusside, when it presents itself as a cream-coloured or 



R. I. A. PROC, SER. II., VOL. III. — SCIENCE. 2 B 



