318 Proceedings of the Royal Irish Academy. 



o£ very thin square or rectangular plates ; and I may also state, that when. 

 the crystals of this salt are exposed to the aii', they become more or 

 less opaque, and present a silky reddish-white appearance. I may 

 further add, that strychnine does not appear to be capable of forming 

 an acid salt with nitroprussic acid. 



Brucine Nitroprmside. 



"When a solution of sodium nitroprusside is added to a soluble salt 

 of brucine, such as the sulphate, a dull yellow precipitate will be im- 

 mediately formed : this, when examined under the microscope, will 

 be found to be more or less crystalline ; and on heating the mixture, 

 as in the case of strychnine salt, it will dissolve completely ; and on 

 cooling it will again reappear, but in a lighter and much more crys- 

 talKne form, consisting of long and slender four- or six-sided prisms, 

 terminating in wedge-shaped ends, and when dry presents a light- 

 yellow colour. Some of the salt obtained as just stated was washed 

 and dried in the manner already described, and a given weight of it 

 being taken, it lost by drying in the water bath, and yielded of silver 

 nitroprusside, quantities of water, and of the silver salt, which agreed 

 very closelv with those which should have been furnished by a salt 

 having the'formula (Co3B:26^"204)^Ho(NO)FeCy5 + 3H,0, in which two 

 atoms of brucine are united to one of nitroprussic acid, and three 

 atoms of water are combined with the salt in its crystalline form ; 

 consequently, I conclude that such is its constitution. 



It is a j^erfectly neutral salt, which is very sparingly soluble in 

 cold water, but dissolves in much larger quantity in hot or boiling 

 Tvater ; and from an experiment I made, I found that the thoroughly 

 <lried salt requii'ed about 736 times its weight of cold, and only about 58 

 times its weight of boiling, water for its solution. It readily dissolves 

 in rectified spirit, and is soluble to a considerable extent in chloroform 

 and in ether, but is much more so in the former than in the latter, 

 and it appears to be almost insoluble in benzole. 



Quinine N'itrojyrussides. 



The alkaloid quinine is capable of forming with nitroprussic acid 

 two salts, viz. a neutral and an acid one. The first was obtained by 

 dissolving quinine neutral sulphate in boiling water, and adding to 

 this solution, whilst still hot, sodium nitroprusside. A solution of 

 this latter salt, on being gradually added di'op by drop to the quinine 

 solution, at first produced no precipitate, or, if any was formed, it was 

 immediately redissolved ; but on continuing its addition, prismatic 

 crystals began to appear, and to increase in quantity. The sodium 

 nitroprusside was added till the mixture acquired a reddish colour 

 from an excess of that salt ; it was then suffered to cool, when a 

 further quantity of the new salt crystallised out ; this was then sepa- 

 rated by filtration, and washed with cold distilled water, to remove 

 the sodium sulphate formed and the excess of sodium nitroprusside ; 



