January li, 1973.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
541 
EXAMINATION OF THE LEAVES OF 
CINCHONA SUCOIRUBRA- 
(especially in reference to the production of 
ALKALOID.) 
BY JOHN ELIOT HOWARD. 
Ill a communication to tlie Pharmaceutical Journal 
(Nov. 4, 1871) in which I described various pro¬ 
ducts of cinchona trees received from India, I 
gave expectation of some further information 
respecting the leaves. 
As I have now had the opportunity of following out 
the investigation of these, I think that it may be 
well to place on record the result, especially as I 
have enjoyed the assistance of the chemical skill of my 
nephew, Mr. David Howard, and having a sufficient 
quantity of dried leaves (about 201b.) at our disposal, 
it is not very probable that we should have missed 
the main object of our researches—the elimination 
of any alkaloid that might he contained. 
This result may be stated as virtually negative; 
for though a few grains of precipitated alkaloid were 
obtained which yielded by further treatment crystal- 
lized cinchonidine, the quantity was so exceedingly 
minute as to suggest the probable explanation that 
the source from whence this product originated was 
rather some fragments of bark of small branches 
accidentally mingled with the leaves than any por¬ 
tion of the leaves themselves. If even the footstalks 
yielded alkaloid, it seems probable that more would 
have been present. The leaves, carefully reduced 
to powder, were divided into different parcels, and 
subjected to various modes of inquiry, in order 
to investigate the different component parts. Of 
these the chlorophyll must be first mentioned, but I 
do not think that our researches added any new 
features to those brought into notice by M. Fremy 
and others (including perhaps the purpuropliylle of 
M. Harsten*) ; then followed the vegetable wax—the 
kinovicacid,—the resin, for the origin of which I am 
inclined to look rather to the stalks of the leaves, as 
I doubt its being a primary product of vegetation. 
Altogether the examination quite precluded the 
expectation of the leaves being ever made use of to 
advantage in the treatment of fevers. In this point 
I find that the observations made by medical men in 
India accord with my own opinion.f Also I must 
mention that it is liighly important and equally 
gratifying to me to know that the researches of Mr. 
Broughton on the leaves are not in disaccord with 
those here recorded. I cannot at present find any 
published report of Mr. Broughton’s analysis, but 
in 18C>9 Mr. B. wrote me as follows:—“ From 20 lb. 
of leaves I have obtained crystallized cinchonidine, 
cinchonine and quinine, but in minute quantities, a 
few grains merely.” Apart from the medical question 
of the utility of the leaves in pharmacy, it is to me a 
satisfaction to be able to decide that the alkaloids do 
not even begin to be formed in the leaves, and that 
their existence is not (except indirectly) connected 
with the chlorophyllian respiration. This view of 
the matter entirely accords with the conclusions 
which I have elsewhere expressed as seeming to 
result from consideration of the manner in which 
the fresh bark filled with alkaloid begins to form on 
4 Poggendorf’s ‘ Amialen,’ t. cxlvi. p. 158. 
f Decoction of cinchona leaves (with acid sulph. dil.) “ was 
found to be a good tonic, hut quite useless as a febrifuge.”— 
‘ Return (E. I. Cinchona Plan*.),’ p. 120. Ordered by the 
House to be printed, June 18th, 1868. 
Third Series, No. 183 . 
the surface of the uninjured cambium. When the 
bark has been stripped off, the fresh material appears 
almost like an exudation,* and this takes place 
with great rapidity, two or three days marking a 
decided commencement of renewal. 1 suppose that 
this results from a rapid multiplication of the vessels 
of the cambium, and that the alkaloids are elaborated 
in those cells of the lax cellular tissue which are 
figured in my ‘ Quinology.’ But the material must 
come from somewhere, and the source cannot be the 
leaves, as the circulation from thence must he im¬ 
peded by the rough treatment of the tree. I con¬ 
clude that the whole plant, in a certain sense, contri¬ 
butes its supplies to any wounded part, and, there¬ 
fore, it would seem to follow that the whole plant 
must he injured by so great a tax upon its resources — 
as will probably be found to be the case. But why 
should the reproduced bark present us with alka¬ 
loids in a purer state than in the original condition 
of things in the plant ? If the supply were drawn 
by any channel from the leaves, it would partake of 
the quality of the leaf products, which is not the case. 
But in the heart-wood the material is abundant, and 
also ready to hand. 
It is instructive to compare this state of things 
with that which is observed in the formation of the 
gall-apple on the oak. Here we find that the punc¬ 
ture and irritation caused by the insect (• Cynips ) in¬ 
duces the tree to form an abundant cellular tissue 
of a somewhat similar construction ; and this be¬ 
comes filled with specially astringent juice, to the 
detriment doubtless of the tree itself. 
I am indebted to the good offices of M. Adolphe 
De Candolle in sending me for comparison a work 
by M. Casimir, the son of this eminent botanist, 
‘ On the Natural and Artificial Production of Cork 
in the Cork Tree.’ It would lead me too far from 
my present subject to follow out the comparative 
physiological changes in the two trees—the Cin¬ 
chona succirubra and the Quercus suher, when sub¬ 
mitted thus to partial decortication. 
I may possibly return to this interesting question. 
In the meantime I may remark that I have de¬ 
scribed (in my ‘ Quinology ’) the mother-substance, 
which seems most probably the one to he modified 
into alkaloid; and I agree with Mr. Broughton in 
the view he has expressed that the first modifica¬ 
tion is into iincrystalliz-able quinine, or into the 
quinicine of Pasteur, which my nephew has recently 
afresh described. From one of these it is probable 
that the molecule or compound atom of quinine is 
built up in a complex manner ; and that the dif¬ 
ference between the first-formed alkaloid and actual 
quinine consists in the addition or subtraction of an 
atom of water; and that not as an hydrate, but pe¬ 
culiarly allocated in the intimate structure of the 
molecule itself. Researches with polarized light 
seem to lead to this view of the matter ; and it is, if 
correct, hostile to the expectation of our being able 
* Mr. Broughton wrote, “ I have long remarked that the 
bark, when carefully removed without injury to the cambium, 
quickly renews itself from below, not from edge.” March 
16th, 1868. Mr. MTvor writes me, June 3rd, 1868,— 
“ The new hai’k rises direct from the sap-wood; if the old 
bark is carefully removed, in three days the new bark is 
formed entirely over the whole surface, i.e. rising directly 
from the sap, and not formed by a current ot cambium from 
under the remaining bark, and so far it is certain that the new 
bark does rise off the sap-wood, and appai’cntly without any 
special action on the part of the leaves.” 
