STRYCHNINE. 
331 
§ 39 6 *] 
The fact that sodium carbonate precipitates, and sodium bicarbonate 
does not precipitate, strychnine, brucine, and veratrine may be utilised 
as an imperfect group reagent, imperfect because long contact with an 
excess of bicarbonate solution precipitates slowly the strychnine alka¬ 
loids ; and a few other alkaloids in dilute solution behave somewhat 
similarly. 
In poisoning by nux vomica there will be the mixed alkaloids to deal 
with, and the processes suggested hitherto for their neat quantitative 
separation do not lead to very good results. Behrens believes that the 
most certain process of recognising strychnine mixed with much brucine 
is to precipitate with platinum chloride in presence of free hydrochloric 
acid. The brucine and strychnine precipitates have different forms and 
grouping. 
The mixed salts may be also turned into the nitrate, potassic nitrate 
added, and then the solution almost saturated with common salt; under 
these circumstances, tables of brucine nitrate first appear, and later 
needles and tufts of strychnine nitrate. 
Fractional precipitation with platinum chloride may also be tried in 
dilute solutions ; with much brucine and very little strychnine the chloro- 
platinate of brucine comes down first, and it is only in the last fraction 
that strychnine comes down. 
To recognise brucine even in traces contaminated with strychnine, 
on the other hand, is much easier ; the solution evaporated with nitric 
acid shows an orange-red edge. 
A striking and very sensitive test is also the double thiocyanate of 
brucine and cobalt. 
This is obtained by adding to a solution of the alkaloid a little 
cobalt chloride solution, and then an excess of ammonium sulpho- 
cyanide ; strychnine, veratridine, and the quinine alkaloids give under 
these circumstances immediate amorphous blue precipitates, but 
brucine crystallises after a minute or two in blue pyramids and tufts ; 
after a time colourless rods of strychnine thiocyanate make their 
appearance. 
The double iodide of bismuth and strychnine forms matted masses 
of needles and isolated dichroic prismatic crystals, and is a good micro¬ 
test. It is best formed by adding a large excess of potassium iodide and 
a very dilute solution of bismuth chloride containing a small amount of 
alcohol, and acidifying with hydrochloric acid ; a drop of this solution 
is added to a drop of an aqueous solution of a salt of strychnine. 1 
The vermin-killers in use in this country are those of Miller, Battle, 
Butler, Clift, Craven, Floyd, Gibson, Hunter, Stenier, and Thurston. 
Ten samples from these various makers, examined by Mr Allen ( Pharm. 
Journal , vol. xii., 1889), gave the following results :— 
1 Emmanuel Pozzi-Escott, Ann. Chim. Anal., 1907. 
