Davy — On some New Organic Nitroprussides. 313 



11. PEELIMnSTAEY KePOKT ON SOME IN'eW OkGANIC NiTEOPETJSSIDES. 



By Edmund W. Dayt, A.M., M. D., M.R.I. A., Professor of 

 Porensic Medicine, Eoyal College of Surgeons, Ireland, etc. 



[Eead, June 14, 1880.] 



The Mtroprussides, or Mtrof erricyanides, a class of salts obtained by 

 the action of nitric acid on the soluble ferro- or ferricyanides, which 

 were first studied by Dr. Lyon Playf air, have not received on the part 

 of chemists the attention that might have been expected from the in- 

 teresting properties possessed by those compounds ; and though it is 

 now over thirty years since they were first investigated, still compa- 

 ratively little has been added to our knowledge of these salts beyond 

 what was ascertained by their original investigator, who described in 

 his classic researches, very fully, the principal characters of nitroprussic 

 acid, and of some of its more important metallic salts. 



As the organic combinations of that acid have received scarcely 

 any attention, and as I thought a field for investigation was therefore 

 open in this direction, I applied last year for a small sum out of the 

 parliamentary grant (given to the Academy for the encouragement of 

 scientific research) to aid me in the necessary expenses attendant on 

 such an inquiry. 



The vegetable alkaloids being as a class the most interesting and 

 important organic bases that we are acquainted with, I naturally di- 

 rected my attention to them in the first place ; and I would now beg 

 leave to lay before the Academy, as a preliminary report on the organic 

 nitroprussides, the facts I have already ascertained respecting the 

 combinations of nitroprussic acid with some of the more important of 

 those substances, which, I should hoj)e, may prove to be of some prac- 

 tical value, as adding to the distinctive characters of the vegetable 

 alkaloids, and thus furnishing some additional means for the detection 

 and separation of those bases under different circumstances. I shall 

 commence by making a few remarks on these salts in general, and 

 afterwards describe some of the more important of them separately 

 in detail. I have ascertained that nitroprussic acid, the composition 

 of which is represented by the formula Ho(!N'0)FeCy5, is capable 

 of forming compounds with the different vegetable alkaloids or bases. 

 These combinations, for the most part, I find to be very sparingly 

 soluble in water ; and, when they are such, they may be readily 

 obtained by treating any of their soluble salts with a solution of 

 sodium nitroprusside, when the alkaloid will be precipitated in union 

 with nitroprussic acid, producing sometimes a very characteristic deposit. 

 On being so formed, the salt will in some cases, as in those of strych- 

 nine and brucine, exhibit itself from the first as a more or less 

 crystalline precipitate ; but in many instances, if the precipitated 

 nitroprusside is examined under the microscope, it will be found to be 



