342 POISONS : THEIR EFFECTS AND DETECTION. [§ 405. 
the stomach) is under examination, it is best to remove the solid sub¬ 
stances by filtration through “glass-wool” or linen, and evaporate nearly 
to dryness over the water-bath, acidifying with acetic acid, and then 
exhausting the residue repeatedly with boiling alcohol of 80 per cent. 
The alcoholic extract is in its turn evaporated to dryness, and taken up 
with water; the aqueous solution is passed through a wet filter, and 
then shaken up with the usual succession of fluids, viz. petroleum ether, 
benzene, chloroform, and amyl alcohol, which will remove a great 
number of impurities, but will not dissolve the strychnine from the acid 
solution. The amyl alcohol may lastly be removed by petroleum ether ; 
and on removal of the final extractive (which should be done as 
thoroughly as possible) chloroform is added, and the fluid is alkalised 
by ammonia, which precipitates the alkaloid in the presence of the 
solvent. Should the reverse process be employed—that is, ammonia 
added first, and then chloroform—the strychnine is not so perfectly 
dissolved, since it has time to assume a crystalline condition. On 
separation and evaporation of the chloroform, the residue (if much dis¬ 
coloured, or evidently impure) may be dissolved in alcohol or benzene, 
and recrystallised several times. Cushman has published an improved 
method of separating strychnine, which, according to test experiments, 
appears to give good results. He describes the method as follows :— 1 
“ The stomach contents or viscera properly comminuted are weighed, and an 
aliquot part taken for analysis. The mass is digested in a beaker over-night, at a 
warm temperature, with water acidulated with acetic acid. The contents of the 
beaker are filtered by pressing through muslin, and then passing through paper. 
The clear filtrate is evaporated on the water-bath to soft dryness, an excess of ordi¬ 
nary 80 per cent, alcohol added, and boiled ten minutes with stirring, and allowed 
to stand one half-hour at a warm temperature. This extraction is repeated, the alcohol 
extracts united, filtered, evaporated to soft dryness, and the residue taken up with 
a little water acidulated with acetic acid, and shaken out with pure acetic ether in a 
separating funnel. Successive fresh portions of acetic ether are used until the solvent 
shows by its colour, and by the evaporation of a few drops, that it does not contain 
extractive matter. As many as twelve extractions are sometimes necessary to accom¬ 
plish this. Care should be taken in each case to allow time for as complete separation 
as possible between the two layers. The purified acid aqueous liquid, which need not 
exceed in bulk 50 c.c., is now returned to the separator, an equal quantity of fresh 
acetic ether added, and enough sodic carbonate in solution to render the mixture 
slightly alkaline, and the separator is then thoroughly shaken for several minutes. 
All the alkaloid should now be in solution in the acetic ether, but a second shaking 
of the alkaline liquid, with acetic ether, is always made, the two extracts united, and 
evaporated in a glass dish over hot water to dryness. It will now be found that the 
residue shows the alkaloid fairly pure, but not pure enough for quantitative results. 
The residue is dissolved in a few drops of dilute acetic acid, warmed to complete solu¬ 
tion, filtered if necessary, diluted to about 30 c.c., and the solution transferred to a 
small separating funnel; 30 c.c. of ether-chloroform (1-1) are now added, and the 
separator shaken. After separation the heavier ether-chloroform is allowed to run off, 
another lot of 30 c.c. of ether-chloroform is added, the separator shaken, and imme¬ 
diately enough ammonia water added to render the mixture alkaline, and the whole 
1 “ The Post-mortem Detection and Estimation of Strychnine,” by Allerbon S. 
Cushman, Ghem. News, lxx. 28. 
