February 10, 1872.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
613 
nicine prepared by himself in 1853, I hope to be 
able either to ascertain or to deny this identity. 
Till then I shall continue to denominate it “ amor¬ 
phous alkaloid soluble in ether.” 
It has been till very recently my opinion that all 
the above-mentioned five alkaloids did not occur to¬ 
gether in any well-defined species of cinchona, but 
that, if they really were found together in a bark, 
that bark was taken from a hybrid. Thus, for in¬ 
stance, I found all five alkaloids in the bark of C. 
HassJcarliana , Miq., which so-called species is no¬ 
thing else but a hybrid of C. Calisaya fructified by 
the pollen of C. Pahudiana. As the C. Pahudiana 
of Java contains cinchonidine, and the G. Calisaya 
of the same locality contains very often quinidine, 
the occurrence of both these alkaloids, together with 
the three others, in the hybrid of these species 
did not surprise me. 
I am, however, now obliged to give up this opinion, 
as I recently found that the bark of C. succirubra, 
grown in Darjeeling, contains all the five alkaloids 
together. As in the red barks from Ootacamund 
which I have analysed I always found cinchoni¬ 
dine and never quinidine, I supposed this fact to 
be a general rule; and, consequently, when I ana¬ 
lysed, in December, 1870, the red bark from Dar¬ 
jeeling sold in October of that year in London, I 
found cinchonidine, but did not search for quinidine. 
I was, therefore, much surprised in finding all five 
alkaloids contained in a sample of mixed rough 
alkaloids,* prepared by Dr. B. Simpson from green 
red bark at Darjeeling. This unexpected fact in¬ 
duced me to make another analysis, both of red bark 
from Ootacamund and of red bark from Darjeeling. 
The result was that I found cinchonidine without 
quinidine in the red bark from Ootacamund, whilst 
that from Darjeeling proved to contain both cincho¬ 
nidine and quinidine. To avoid the mistake of again 
overlooking one of the alkaloids which might be 
contained in a given bark, I now use another method, 
which is based upon the following facts :— 
1. The great solubility of quinine and amorphous 
alkaloid in ether, and the relative insolubility of 
quinidine, cinchonidine and cinchonine in this 
liquid. 
2. The great solubility of the iodo-sulphate of the 
amorphous alkaloid in alcohol, and the very small 
solubility of the iodo-sulphate of quinine (liera- 
patliite) in this liquid. 
3. The great difference in solubility between the 
tartrate of cinchonidine and the tartrates of cincho¬ 
nine and quinidine,—the first being soluble in 12G5 
parts of water at 10° C.,f the second hi 35 - G parts of 
water at 10° C.,f and the third in 38‘8 parts of 
water at 15° C.J 
4. The great difference in solubility between the 
liydriodate of quinidine and the liydriodates of cin¬ 
chonidine and cinchonine in water and alcohol. 
1 part of liydriodate of quinidine requires 1250 
parts of water at 15° C., or 110 parts of alcohol. 
1 part of liydriodate of cinchonidine requires 110 
parts of water, or 3 parts of alcohol. 
* Broughton’s amorphous quinine. 
f O. Hesse, Annalen dev Chemie und Pharmacie, vol. 
cxxxv. p. 337. 
X O. Hesse, Ibid. vol. cxlvi. p. 357. The numbers ob¬ 
tained by my own experiments in this direction differ only very 
slightly from those obtained by Hesse. This difference is, 
therefore, of no consequence for the practical application. 
1 part of liydriodate of cinchonine requires 128 
parts of water, or 3 parts of alcohol. 
These facts are applied to the separation and de¬ 
termination of the different cinchona alkaloids in the 
following manner:— 
5 grams* of the pulverized mixed alkaloids are 
mixed with 50 grams of ether, and the mixture, 
after well shaking, left at rest till the next day. 
By tills operation the alkaloids are separated into 
two parts, viz. one part soluble in ether, and another 
part insoluble in that liquid. The part soluble in 
ether contains the quinine and the amorphous alka¬ 
loid, together with traces of quinidine or cinchoni¬ 
dine, whilst the insoluble part contains the cin¬ 
chonidine, cinchonine and quinidine. These two 
parts are separated by a filter, the insoluble part 
washed with some ether, and the ethereal solution 
either evaporated or distilled. 
A. Part soluble in Ether. 
The residue left by the evaporation of the ether 
is dissolved in 10 parts -of proof spirit acidulated by 
one-twentietli of sulphuric acid. To this solution 
is carefully added an alcoholic solution of iodine till 
a precipitate is no longer formed. This part of the 
process is the most difficult, and requires some expe¬ 
rience. If the mixed alkaloids contain a large 
amount of quinine, there appears immediately a 
black precipitate of quinine-herapathite, whereby the 
addition of the solution of iodine is regulated; but 
if the amount of quinine is only very small, it may 
happen that the precipitate of lierapathite does not 
appear immediately. In such a case only a small 
quantity of iodine must be added, and the liquid, 
after having been stirred by a glass rod, left till the 
next day. If quinine is really present, it will then 
be precipitated in the form of lierapathite. The 
chief desideratum of this part of the process is to 
add enough and not too much iodine. The liera- 
patliite is collected upon a filter, washed with strong 
alcohol, dried upon blotting-paper, and heated in a 
water-bath. One part of the lierapathite, thus 
dried, represents 0'5G5 part of pure quinine. 
The liquid separated from the lierapathite is mixed 
with an alcoholic solution of sulphurous acid, whereby 
the iodo-sulphate of amorphous alkaloid is converted 
into liydriodate, and the red-brown colour disap¬ 
pears. The solution is then carefully neutralized 
by caustic soda, and heated on a water-bath to expel 
the alcohol, after which it is precipitated by a slight 
excess of soda. The precipitate consists of the 
amorphous alkaloid, containing traces of quinidine 
or cinchonidine, if these alkaloids were contained in 
the mixed alkaloids. 
B. Part insoluble in Ether. 
This part is mixed with 40 parts of hot water, and 
converted into neutral sulphate by careful addition 
of diluted sulphuric acid, so that a solution is ob¬ 
tained having a slight alkaline reaction upon red 
litmus paper. To this solution a solution of tar¬ 
trate of potash and soda is added in sufficient quan¬ 
tity to convert the sulphates into tartrates, and, 
after stirring with a glass rod, it is left till the next 
day. If cinchonidine be present in appreciable 
* The mentioned quantity is the minimum which I use for 
this determination, but, if possible, I prefer to use a larger 
quantity. 
