/. W. Langley on Detection of Picrotoxine. 1 1 1 



It is extremely probable that this color is produced from a 

 trace of some nitrogenous body which pertinaciously adheres to 

 the picrotoxine, as, on analysis, traces of nitrogen can be de- 

 tected; but this body powerfally resists all attempts at separa- 

 tion, for when repeatedly crystallized the picrotoxine still retains 

 a minute portion of it. It can be obtained perfectly free from 

 nitrogen only by dissolving it in potassa and precipitating it by 

 acids. When thus prepared its properties are the same as before 

 with the exception of the purple color produced by oxydation 

 and subsequent treatment with alkalies. 



There is no substance at present known to the writer which, 

 gives this shade of color under these circumstances. There are two 

 however which communicate a brownish-yellow to the fluid, and 

 would, if present as an impurity, interfere with the distinctness 

 of the reaction, these are sugar and strychnia ; from the first we 

 need suffer no inconvenience as it is perfectly separated in the or- 

 dinary method used for isolating the alkaloids ; from the latter, 



remainmg as a salt dissolved in the water and the ether ( 

 j,Qg all, or nearly all, of the picrotoxine. To prove this the 

 loUowmg experiment was tried. A quart of ordinary ale was 

 divided into equal portions ; into one '045 gram, of picrotoxine 

 aid a little strychnia were introduced, the other was unadultera- 

 ted ; both were acidulated with hydrochloric acid, and agitated 

 ^vith ether ; tlie ethereal solutions on evaporation yielded, in the 

 Qrat case, small microscopic crystals of picrotoxine mixed with a 

 httle extractive matter perfectly free from strychnine; the other 

 yielded extractive matter alone. The test of sulphuric acid and 

 titrate of potash was then applied ; the brownish-red color was 

 produced in the first case, in the second there was no change. 

 -^0 ascertain the readiness with which minute quantities of picro- 

 ^;xiDe can be detected /^ of a gramme of it was dissolved in a 

 Nit of ale; this was acidulated and treated as above; the ethe- 

 real extract furnished ample proof of the poison when tested. 

 nn ^'I'^^^er experiment the stomach of a cat which had been 

 poisoned was emptied of its contents so that only the picrotoxine 

 aosorbed by the coats of the stomach might be extracted. It 



as treated with alcohol and the solution evaporated to dryness, 

 ^cidu ated water being poured on the residue, the .picrotoxine 

 ^^ahttle organic matter were dissolved; being now treated 

 ^th ether and the solution evaporated, small crystals of picro- 

 J^^ine were obtained, which, when tested, produced the charac- 

 tr" t S ^^^ *^^^°^" ^ portion of animal matter free from poison 



J *^ in the same way gave no discoloration, 

 acid If ^°^^^ing a liquid for picrotoxine it should first be rendered 



^'^en shaken with ether; the residue left on evaporation of 



