flame and odour of burning wood, and with a mere trace of earthy residue, and therefore ap.
parently woody fibre, or lignin. The analysis of two samples gave results nearly concordant,
as follows. One hundred grain were used, aud all visible fragments of wood were excluded
First. Second.
.. 64.3 65.0
.. 20.7 19.7
.. 6.2 5.0
.. 4.4 6.2
.. 4.0 4.2
Total..7 . 99.6 100.1
Arahin, dried at 26U° .
Fecula, dried at 212°.
Lignin, dried at 212°.
The proportion between the gum and the resin is here identically the average proportion
already mentioned as existing in Pipe gamboge; so that, on simply abstracting the fecula and
woody fibre an article is constituted of precisely the same chemical composition. 1 his circumstance,
coupled with the presence of the particular principle fecula and the vesicular structure
of the cakes renders it extremely probable, if not certain, that cake gamboge is not simply
a natural production, but rather a manufactured substance—an adulteration For in the first
„lace it is the pure exudation plus so much impurity; secondly, fecula is not known to he produced
from the trunks, branches, or leaves of plants belonging to that part of the botanical
system in which the true Gamboge tree undoubtedly will be found to be properly placed, and it
is therefore almost impossible that its.presence depends on some mere variety in the period of
collection or other circumstance in vegetation ; and thirdly, the vesicular texture, so different
from the compact, uniform texture of Pipe gamboge, is exactly what might be expected from
the process of wetting the exuded juice, beating it up with other pulverulent substances and
then drying it. I t might be objected that eleven per cent, of foreign matter is a small addition
for an adulteration. But this amount may, after all, he quite equivalent to the grower’s profit
from the pure article ; and it will presently be seen, that a larger proportion of adulteration
may so dilute the yellow tint of the mixture as to render it almost unmarketable,
Chemical Composition of
Resin, dried in the oil-bath at 380°...
coarse Gamboge.
First.
.............. .. 61.4
...... ................ 17.2
Second.
35.0
14.2
..................... 7.8 19.0
...................... 7.8 22.0
Moisture disengaged at 350°............... ...................... 7.2 10.6
Total___ 101.4 100.8”
Chemical Composition op Ceylon Gamboge. _ ,,, ,
“ The following results were obtained from three analysis of Mrs. Colonel Walker s specimens,
evidently different in purity. The quantity used was one hundred grains..
First, gecond. Third.
Resin, heated at 400°........................ 68.8 71.5 I 72.9
Arabin, dried at 240°.......... 20.7 18.8 19.4
Fibre of wood and bark, a t 212°................ 6.8 5-7 4.3
M o is tu r e '.,................................................. 4.6 not ascertained.
Total. 100.9 96.0 96.6
Moisture not reckoned.
Here it is evident that the proportion of gum and resin to one another is as nearly as possible
the same, with their proportion in some specimens of Çne Pipe gamboge.
1 November 28iA.—To the observations made above, on the external characters and composition
of the different kinds of Gamboge, it may be well here to annex a brief-notice ot tne
gambogioid juices obtained from two trees, which have been at different times supposed by
some to yield the genuine drug, namely, the Gamma cambogia, and Xanthochymus yictonus.
ILLUSTRATIONS OF INDIAN BOTANY. 119
f am here again indebted to Mrs. Colonel Walker for my subjects of analysis, having very
lately received splendid specimens of the barks of both trees, with their exudations concreted
on them. ‘ r
The exudation of Garcinia cambogia, as I am informed by Mrs. Walker, concretes slowly
and imperfectly, so as to remain long viscid in the climate of Ceylon. The specimens sent to
me, on arriving here, still continued soft enough to receive the impression of the fingers when
squeezed between them. The exudation was chiefly in the form of long slender tears, of a
clear lemon-yellow tint, without odour or taste, of a distinct resinous appearance, both externally
and in their fracture, and wholly incapable of forming an emulsion when rubbed with the
wet finger. These properties are alone sufficient to establish it as a substance altogether distinct
from true Gamboge; and this distinction is still further shown by its chemical composition.
Suspecting that its softness was owing to the presence of volatile oil, T distilled 50 grains
of it with water in an apparatus, in which it was easy to measure any fluid given off, to the
fourth part of a grain ; and after repeated cohobation, there were obtained six grains of a lively
yellow volatile oil, possessing a faint turpentine odour. From another portion, weighing 20
grains, the resin and volatile oil were removed conjunctly by sulphuric ether; and then cold
water took up a principle agreeing entirely with Arabin in its characters; after which there was
only left a little dark, brittle, fibrous matter, evidently from particles of the bark. The analysis
gave the following results :
Per cent.
Resin...............................................................; ...................... 66.0
Arabin................................................................. 14.0
Volatile oil............................. 12.0
Fibre of the bark...................................................... 5.0
Loss ......................... . ....................................................... 3.0
100.0
It is not a little remarkable that this exudation, evidently a true gum-resin, and containing,
too, a considerable proportion of gum, is nevertheless not emulsive. The resin differs
essentially from that of true Gamboge, being somewhat less soluble in ether or rectified spirit,
and possessing a colour somewhat different both in tint and in intensity. Its colour is not
orange, but rather lemon-yellow; and its solution is so much less intense in tint than that of
the resin of Siam or true Ceylon Gamboge, that the last two present an equal depth of s'hade
when dissolved in ten times as much spirit as the other.”
“ Mr. Royle having expressed an opinion in his Illustrations of the Botany of the Hima-
layah mountains, that a kind of Gamboge may also be produced by another species of the natural
family Guttiferce, namely, the Xanthochymus pictorius,* it seemed to me desirable to determine
that point also by an analysis of its resinous exudation, which Mrs. Walker’s specimens,
have put it in my power to accomplish.
The exudation on the bark of this speciqs is even more different in appearance from true
Gamboge, than that of the Garcinia cambogia. It forms small tears of a pale greyish-green
colour, sometimes also pale yellowish-green; and it is translucent like a resin. It does not
form an emulsion at all when rubbed with the wet finger. It is pretty hard, and in cold weather
pulverizable.
From the facility with which it softens when heated, it probably contains some volatile o il;
but my specimen could not afford me enough for ascertaining that point with care. For the
same reason I could not attempt an exact quantitative analysis of its other component parts.
But it is evidently a true gum resin, containing,.however, less gum than that of the Hebraden-
dron. Sulphuric ether removes a pale greenish-yellow resin, leaving an opaque glutinous mass,
which is broken up and partially dissolved by cold water. The watery solution froths on agitation,
and when evaporated leaves! a viscous matter, evidently Arabin, or soluble gum. A small
quantity of fibrous impurities and fleecy particles remains unattacked by the ether and cold
water. One grain and seven-tenths of the gum resin yielded 1.3 of resin, 0.3 of gum, and 0.2
of fibre, that is, 76.5, 17.6, and 5.9 per cent. This result seems to indicate the absence of
* Illustrations, &c. p. 132, part iv,-^1834.