250 ON TESTING OF CINCHONAS BY MEANS OF CHLOKOFORM. 
orate the chloroform, and the residue is treated with water acidu- 
lated with hydrochloric acid, which dissolves the whole of the 
cinchonine and a portion of the cinchonic red. It is then to be 
filtered, and solution of ammonia diluted with fifteen or twenty 
times its volume of water added to it. This addition is made drop 
by drop, keeping it continually stirred ; as soon as a white cloud 
appears which is not dispersed by the agitation, a sufficient quan- 
tity of the solution has been added. This part of the process 
effects the precipitation of the cinchonic red without touching the 
cinchonine. It is easy to determine when to terminate this part 
of the process, as the cinchonic red is precipitated in the form of 
reddish brown flakes, and the cinchonine, on the contrary, in white 
curdled flakes. When a sufficient quantity of dilute ammonia has 
been added, the liquor, which ought to be colorless, is filtered ; 
the filter then washed with a little distilled water, and the united 
liquors precipitated by an excess of ammonia ; the precipitate, 
which consists of pure cinchonine, whose chemical properties it is 
easy to determine, is then collected, dried, and weighed. 
The first experiment yielded me 2.9 grains of cinchonine, and a 
second produced three grains. In taking the highest figure, we 
have 75 grains of alkaloid in 21bs. 8oz. of grey cinchona. 
Test of Yellow Cinchonas. — It is not necessary to operate on 
more than five drachms of the yellow cinchona bark, as the pro- 
portion of organic alkali in this variety of cinchona is much greater 
than that of the grey cinchona. 
Five drachms of yellow cinchona, powdered, and passed through 
a fine horse-hair sieve, are to be exhausted with acidulated water, 
as in the case of the grey cinchona. The addition of the liquor is 
to be discontinued when it passes through colorless and insipid : 
we thus obtain from five to six ounces of liquid, to which lj 
drachms of caustic potash and five drachms of chloroform are 
added. These are to be agitated for a short time, and afterwards 
allowed to subside ; there is then a dense whitish deposit formed, 
consisting of quinine, cinchonine, and chloroform ; sometimes the 
separation is complete and effected in an instant, leaving a red 
transparent liquid floating on the surface, which may be immediately 
poured off ; the chloroformic solution is then washed, collected in 
a small capsule, and by the spontaneous evaporation of the chlo- 
roform, the alkaloids remain in a pure state. 
