THF TROPICAL AGRICULTURIST. [November i, 1888. 
THE HYBRIDISATION OF CINCHONAS* 
By David Hoopfr, r.c.s., f.i.c, Government 
QUINOLOGIST. 
■ Cinchona hybrids have received a great denl of atten- 
tion from a number of botanists, and in the present 
paper the author treats the subject, so far as cinchona 
is concerned, in the light of the chemical analysis 
of the barks. 
Between 0. succirubra and C. officinalis many hybrid 
barks are recognised, and have been cultivated and 
exported to a very large extent. The facility with 
which these plants made their appearance on the 
estates seems to imply that forms of cinchona were 
produced that were more adapted to the climate and 
situation of their adopted country than the parent 
forms brought originally from South America. Those 
having a greater vigour of growth should be propagated, 
as the robust habit is usually indicative of a richer bark. 
Hybrids assume the quick growing character 
of the succirubra, yet they contain a greater proportion 
of quinine than that species. Thpy do not, as a rule, 
contain the percentage of quinine usual to officinalis, 
but the large quantity of bark yielded by the trees and 
the high total alkaloids make them equal in value to 
the best crown barks. 
The author proceeded to give the alkaloidal composi- 
tion of two species between which hybirdisation on 
the plantations has taken place, the natural stem bark 
beiug selected. The results were given in a table 
representing fifty selected red barks, the quinine ran- 
ging from 17 to 27 per cent., cinchonidine from 26 to 
51 per cent., cinchonine from 17 to 47 percent., and 
amorphous alkaloids from 4 to 23 per cent.; besides 
these the alkaloid quinidine occurred in traces in red 
barks, and occasionally reached 0'5 per cent. 
The average of the fifty total alkaloids was 6 25 per 
cent. The table further showed that, with the ex- 
ception of five samples, all were official barks. Dur- 
ing the discussion on the present Pharmacopoeia, a 
critic remarked that the test admitted barks contain- 
ing 2J per cent- of quinine and § per cent, of cin- 
chonidine or those containing ^ per cent, of quinine 
and 2j per cent, of cinchonidine with 3 per cent, of other 
alkaloids, but it was the opinion of the author that it 
would be very surprising to find such an erratic composi- 
tion in any one kind of cinchona. 
The average composition of the alkaloids, derived 
from the foregoing analyses, shows the following per- 
centage composition: — 
Quinine ]-40 
Cinchonidine 225 
Cinchonine ' 1-92 
Amorphous alkaloids -68 
6-25 
In cinchona officinalis there is a different arrange- 
ment of alkaloids, fifty specimens showing that the 
quinine ranged from 48 to 62 per cent., the cinchonidine 
from 18 to 33 per cent., the quinidine from 0 to 6 per 
cent., the cinchonine from 2 to 16 per cent., and 
amorphous alkaloids from 4 to 13 per cent. 
The crown barks in this table give an average of 5'25 
per cent, of total alkaloids, viz. : — 
Quinine 293 
Cinchonidine 1'40 
Quinidine '08 
Cinchonine '42 
Amorphous alkaloids '42 
5-25 
Calculating from these figures, a hybrid of the two 
species ought to yield : — 
Q . nine 2'16 
Cinchonidine ••• ••• ■■• ••• T82 
Quinidine '04 
Cinchonine 1 1 17 
Amorphous alkaloids "56 
5.75 
Analyses of twenty-five specimens of hybrid bark 
(muynifot ia and pvbescens) i-howed that the centesimal 
composition of the total alkaloids gave on anaverag'e: — 
Quinine 412 
Cinchonidine ... ... 409 
Quinidine ... ... ... 0'5 
Cinchonine ... 9-7 
Amorphus alkaloids 7'7 
The following analyses show the distribution of the 
alkaloids in individual barks: — 
1 Hybrid 
la ,, 
2 „ 
2a „ 
& 
332 
2-58 
•87 
■90 
a 
o'S 
299 
291 
•98 
2-75 
•13 
6 © 
-a a 
§~ 
3 a 
•41 
•43 
2-90 
1-05 
O 3 *rS 
•63 
•70 
•40 
7-21 
655 
564 
5-10 
* Papers by Mr. David Hooper read at the annual 
meeting of tho Pharmaceutical Society by Dr. Thresh 
The two barks marked " 1 " and " la " are in 
appearance like the pubescent hybrid, and their analysis 
confirms to some extent the resemblance, in that they 
contain a large proportion of quinine and cinchonidine 
in their alkaloids. Nos. 2 and 2a huve the habit of the 
magnifolia hybrid, but the presence of quinidine and 
the large amount ot cinchonidine and cinchonine res- 
pectively indicate new features in the alkaloidnl com- 
position that might be referred to new forms produced 
by hybridisation. 
Some analyses of hj brids grown in the Eengal Govern- 
ment cinchona plantations, atMongpoo, near Darjeeling, 
at 3,500 feet elevation, showed the difference between 
hybrids from foreign localities grown in the same 
situation. The three kinds were from trees raised from 
seed from Jamaica, the Nilgiris and Monpoo, and each 
sample was taken in strips from about forty trees of 
varying types. 
Jamaica. 
Nilgiris. 
Mongpoo. 
Quinine 
2-22 
2-47 
2-02 
Cinchonidine 
1-93 
1-98 
250 
Quinidine 
17 
Cinchonine 
•75 
•58 
66 
Amorphous alkaloids 
•61 
•59 
•31 
5'54 
5-62 
5-66 
In concluding, the author expressed the hope that lie 
might in a future communication give the results of a 
large number of analyses of the ledger-hybrid, a cros? 
between O. ledgeridna and C. succirubra, — Chemist and 
Druggist, 
♦ 
CARTHAGENA BARK. 
By David Hooper. 
In the initiatory part of this paper the author gave 
some historical data regarding the barks bearing the 
name of Carthagena in the United States of 
Colombia. 
Jose Oelestino Mutis explored the bark region of 
New Granada in 1772, but it would seem that he was 
not acquainted with the more valuable species of 
cinchona. 
Alexander von Humboldt, who visited the ports of 
the Caribbean Sea in 1801, stated then that " the 
proximity of the port of Carthagena would render 
the neglected cultivation of cinchona an object of 
great importance to European trade ; while Dr. Karsten, 
a German botanist, stated in 1844, as the result of a 
long residence in South America, that he found Cin- 
chona lancifolia of Mutis to be a very variable plant, 
and to furnish barks of very different appearance. 
This species, he says affords principally two kinds of 
barks : the valuable variety called soft Colombian, or 
Calisaya, or Santa Fe, and the less valuable variety, 
called Carthngena, or Oogneta bark, or Carthagene 
ligneux of the French, About the year 1872 Colombiau 
barks were again in the market, and 12 cwt. was 
shipped to Europe from CartbageDa and neighbour- 
ing ports. After referring to the production of bark 
in the United States of Colombia at the present time, 
Mr. Hooper proceeded to state that Mr. Kobert Cross 
was employed in 1877-1878 to collect plants of the 
Cali.:aya Santa Fe on the eastern Andes, and of the 
