76 CINCHONA BARKS. 
2. For QUININE. 
“To the total alkaloids from 20 grams of Cinchona, previously 
weighed, distilled water, acidulated with diluted sulphuric acid, is 
added, until the mixture remains for 10 or 15 minutes after diges- 
tion just distinctly acid to test-paper. It is then transferred to a 
weighed beaker, rinsing with distilled water, and adding of this 
enough to make the whole weigh 70 times the weight of the alka- 
loids. Solution of sodium hydrate, previously well diluted with 
distilled water, is now added, in drops, until the mixture is exactly 
neutral to test paper, digested at 60° C. (140° F.), for 5 minutes, 
then cooled to 15° C. (59° F.), and maintained at this temperature 
for half an hour. If crystals do not appear in the glass vessel, the 
total alkaloids do not contain over 8 per cent. of their weight of 
quinine (corresponding to 9 per cent. of crystallized sulphate of 
quinine). If crystals appear in the mixture, the latter is passed 
through a filter not larger than necessary, prepared by drying two 
filter papers of 5 to g centimeters (2 to 3.5 inches) diameter, trim- 
ming them to an equal weight, folding them separately, and placing 
one within the other so as to make a plain filter fourfold on each 
side. When the liquid has drained away, the filter and contents 
are washed with distilled water of a temperature of 15° C. (59° F.), 
added in small portions, until the entire filtered liquid weighs 90 
times the weight of the alkaloids taken. The filter is then dried, 
without separating its folds, at 60° C. (140° F.), to a constant 
weight, allowed to cool, and the inner filter and contents weighed, 
taking the outer filter for a counter weight. To the weight of 
efloresced quinine sulphate so obtained, 11. 5 per cent. of its 
amount is added (for water of crystallization), and 0.12 per cent. 
of the weight of the entire filtered liquid added (for solubility of 
the crystals at 15° C. or 59° F). The sum in grams multiplied by 
5 equals the percentage of crystallized quinine sulphate equivalent 
to the quinine in the cinchona.” 
For the preparation of the extracts and tinctures, as also for the 
direct application of the bark in dispensing, it suffices to know the 
total amount of alkaloids. One must furthermore convince him- 
self that quinine is present, by dissolving 1 part of the crude alkaloid 
in the smallest possible quantity of hydrochloricacid, precipitating the 
bases with caustic soda, decanting the liquid, and agitating the 
deposit with 20 parts of ether. The etherial solution is allowed to 
_ €vaporate, and 1 part of the residue boiled with 300 parts of water 
and filtered, when, upon cooling, some quinine Separates out. If 
