2 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[July 1, 1871 
requisite to measure accurately the deviations is that 
the solution is colourless, and till now I have not yet 
succeeded in obtaining this desideratum, but have 
been obliged to be satisfied by obtaining solutions 
which had a slightly yellow colour. I obtained these 
solutions as follows :—After ascertaining the total 
amount of alkaloids in a bark, the alkaloids were 
dissolved in weak acetic acid, and to this solution 
added a few drops of basic acetate of lead. After 
separating the lead by a current of sulphuretted hy¬ 
drogen the liquid, much discoloured by the precipi¬ 
tated sulphide of lead, was filtered, and the alkaloids 
precipitated by caustic soda. The precipitate being 
washed and dried, one may proceed to prepare the 
solution for the optical observation. The alkaloids 
are accurately weighed, and the determined weight 
called j). This quantity is dissolved in diluted sul¬ 
phuric acid, and the volume of the solution accurately 
measured.* Tliis volume is called V, and filtered 
immediately into the tube, in which it will be ob¬ 
served. This tube has a length of 100 millimetres. 
After the tube has been completely filled and closed, 
and it has been ascertained that its contents are per¬ 
fectly clear and transparent, it can be observed in 
the instrument.! If the different alkaloids are pre¬ 
sent in such quantities that their opposite deviations 
neutralize each other, the molecular rotation is = 0°, 
and this result needs only to be noted. If, however, 
a deviation is observed, this deviation is noted as a° 
= to the amount of degrees of deviation observed, 
either to the right or the left; for instance, a° = 3°^ , 
or a° = 3° *c., etc. One has now the necessary data 
to calculate the molecular rotation = [a]j of the 
mixed alkaloids by using the formula:— 
[ a ]j = ■■ U 2 y— ^ or + 
After tliis determination another part of the alkaloids 
is treated with ether, and the deviation of the part 
insoluble in ether determined in the same way. By 
these two determinations one obtains two data, which, 
notwithstanding the still existing imperfections of 
the method, will prove to be of great utility in the 
investigation of cinchona barks, as may be seen by 
the following observations made by Dr. B. Simpson 
and myself. 
2. C. Calisaya, from Java. 
Bark from a branch. 
Total amount of alkaloids 0 - 84 per cent, [a] j = 
140°- 6 
The alkaloids contained a large amount of quinidine. 
3. C. Paliudiana, from Java. 
Hoot-bark. 
Total amount of alkaloids 1* * * § 5 per cent, [a] j = 26°‘35 
*C. 
4. C. succirubra, from Darjeeling. 
Stem-bark of plants 3^- years old. 
Total amount of alkaloids 5'G per cent, [a] j = 13°59 
The alkaloids consisted of quinine, cinclionidine (both 
laevogyre), cinchonine and amorphous alkaloid 
(both dextrogyre). 
5. C. succirubra from Ootacamund. 
Renewed bark (fourth harvest). 
Total amount of alkaloids, 9 per cent, [a]j=55 0 'o*r. 
The part insoluble in ether proved [a]j=19°*8 f y . 
The same alkaloids as in 4, but more cinclionidine 
and less cinchonine. 
6. C. officinalis from Darjeeling. 
Stem-bark (one year covered by moss). 
Total amount of alkaloids 7’G8 per cent, [a 
56°-35*t. 
The part insoluble in ether proved [a] j = 13 o- 20 < V-. 
The same alkaloids as in 4 and 5, but much more 
quinine, of which the quantity amounted to 3 4 
per’cent. 
7. G. officinalis from Ootacamund. 
Renewed bark (second harvest). 
Total amount of alkaloids, 8 per cent. [«]j = 
139°-49*tv. 
The same alkaloids as in G, but containing much 
more quinine ; they were almost entirely soluble 
in ether. 
B.— Observations by Myself. 
1. G. Calisaya from Darjeeling. 
Bark of trees three years old. 
Total amount of alkaloids, 3 per cent, [a] j = 
120°7-7. 
The part insoluble in ether proved [a] j = 174° - 34 . 
The alkaloids consisted of cinchonine, quinine, amor¬ 
phous alkaloid and cinclionidine. 
A. Observations by Dr. B. Simpson.§ 
1. C. Calisaya, from Java. 
Stem-bark. 
Total amount of alkaloids L3G per cent, [alj = 
lG0-5° A. 
The alkaloids contained chiefly quinidine. 
* Weight and measure are of the metric system. 
+ The instrument used by me is the polaristrobometer, of 
Wild. It is, however, clear that any other good instrument 
may be used. 
j Although the sulphide of lead has a very favourable ac¬ 
tion in taking away a great part of the colour of the solution, 
its action is not the same with all kinds of bark. I am there¬ 
fore unable to state with certainty the quantity of alkaloids 
which ought to be dissolved in a certain volume. It is de¬ 
sirable to make a solution which contains Ol of the alkaloids. 
This is, however, in general not possible, because of the too 
intense colour, wherefore the quantity of the alkaloids in the 
solution varies between 04 and 0 - 05. 
§ These observations have been made by Dr. B. Simpson, 
Surgeon, of the Bengal Army, in my laboratory at the Hague, 
in February 1870. 
2. G. hybrida from Darjeeling, probably from G. 
Calisaya and C. officinalis. 
Bark of trees three years old. 
Total amount of alkaloids, 3’24 per cent, [a]j = 
^ I78°*r. 
Tlie alkaloids consisted of quinine, cinclionidine, 
amorphous alkaloid and very little cinchonine. 
The part insoluble in ether was too small for ob¬ 
servation. 
3. C. succirubra from Darjeeling. 
Stem-bark, sold in London in October, 1870. 
Total amount of alkaloids 6 per cent, [a] j = 24°T r ?'. 
The alkaloids consisted of cinclionidine, cinchonine, 
amorphous alkaloid and quinine. 
4. C. officinalis from Ceylon. 
Bark sold in London in November, 1870. 
Total amount of alkaloids 57 per cent, [a]j = 
145°-8<Y. 
The part insoluble in ether proved [a]j = DU'OGV. 
The alkaloids consisted of quinine, cinclionidine, 
amorphous alkaloid and cinchonine. The quan¬ 
tity of pure quinine amounted to 37 per cent. 
