258 POISONS : THEIR EFFECTS AND DETECTION. [§ 315 . 
than the sulphates, and, therefore, sulphuric acid being the more suitable 
to use ; the solutions must not be too dilute. 
Dragendorff’s process, or modifications thereof, is seldom employed 
now for the direct extraction of poisons, but is useful for the investi¬ 
gation of the extracts obtained by the Stas-Otto process. 
Kippenberger’s modification of Dragendorff’s process is as follows : 1 
—The fluid should be as free from mineral salts as possible. This 
is accomplished by evaporating an aqueous, slightly acid extract to a 
syrup, and treating with absolute alcohol. The alcohol is driven off, 
and sometimes the alcoholic extract is again treated with absolute 
alcohol, the final extract being dissolved in water and acidified with 
sulphuric acid until it contains at least 1 per cent, free sulphuric acid ; 
it is warmed to 30° C., allowed to cool, and then shaken up twice with 
petroleum ether (b.p. 30°-50°) in a separating funnel. 
The petroleum ether extracts fat, fatty acids, veratroidin, jervin- 
xanthin bases, and other matters. 
The petroleum ether remaining in the fluid is completely got rid of 
by evaporation in the water-bath, the extract cooled, and shaken up with 
chloroform; this removes from the acid solution colchicine, digitalin, 
picrotoxin, cantharidin, papaverine, aconitine, narceine, jervin, 
geisospermin, caffein ; it also extracts some delphinine, brucine, 
emetine, and thebaine, and mere traces of narceine, strychnine, 
veratrine, and cocaine. 
The acid liquid may now be alkalised with weak soda solution, and 
shaken with chloroform. The chloroform extracts sparteine, coniine, 
nicotine, atropine, codeine, emetine, brucine, strychnine, veratrine, 
delphinine, pilocarpine, apomorphine, hyoscyamine, daturine, scopola¬ 
mine, and alkaloids generally soluble in chloroform ; it must be noted 
that in the alkaline liquid there may remain morphine, narcotine, papa¬ 
verine, aconitine, and caffein. To the alkaline fluid is now added a 
concentrated solution of sodic bicarbonate and common salt, the latter 
in the proportion of 15 grms. per cent., and the liquid again treated 
with chloroform to which 10 per cent, alcohol has been added ; this 
dissolves out morphine, narceine, and strophanthine. 
If the shaking-out process of Dragendorff is applied to quite small 
quantities of fluid, say up to 50 c.c., derived from an alcoholic extract, 
there is seldom any practical difficulty in its execution ; if, on the other 
hand, solutions containing mucus, peptones, albumoses, and carbo¬ 
hydrates are treated by the volatile solvents, emulsions are obtained, 
difficult to separate. Some partial success in separation is possible by 
warming the mixture, and also by whirling the separating funnel and 
its contents in a centrifugal apparatus ; but unless neat, well-defined 
separations occur, the process should not be used. 
1 Zeit. /. anal . Chemie, 1900, p, 290. 
