238 
Where several cylinders have been joined 
together, and squeezed into a cake or ball, 
the mass is usually wrapped in large leaves, 
which appear to belong to a malvaceous or 
bombaceous plant. Pipe Gamboge is very 
brittle, and presents a somewhat conchoidal 
fracture, the surface of which is smooth, 
brownish-yellow in tint, and glimmering in 
lustre. It becomes bright Gamboge-yel- 
low wherever it is frayed or rubbed, and 
very readily forms an emulsion or paste of 
e same hue when rubbed with the wet 
finger. It has scarcely any taste ; but after 
a short time produces a sensation of acrid- 
ity, especially in the back of the throat. 
Neither hasit any smell; yet the fine dust, 
raised in pulverizing it, quickly irritates 
the nostrils, even in quantities inconceiv- 
ably minute, exciting a profuse flow of 
mucus, and some sneezing, but without 
ai 
n. 
This variety of Gamboge is familiarly 
known to be an excellent and powerful 
purgative, which in the dose of three, five, 
and seldom more than seven grains, pro- 
duces profuse watery discharges; nor has 
dreading its effects, as our predecessors 
did; for its action is seldom or never ac- 
companied with much pain or other uneasi- 
"a ept il 7 L4 J ee | 
nes 
, “ones 
other finely-pulverizable substance, such 
as cream of tartar. Yet on the other hand, 
it is a dangerous poison in large doses; 
one drachm has proved fatal; and the cause 
of death is violent inflammation of the 
bowels, I believe that the occasionally 
fatal effects of a nostrum much in vogue 
in the present day, under the name of Mor- 
ison’s Pills, have been satisfactorily traced 
to an over-dose of Gamboge. 
It was this variety which Braconnot ana- 
lyzed. As for the analysis of Professor 
John, which seems also to have been ap- 
plied to the Pipe Gamboge, it differs so 
entirely from what I have obtained from 
all the varieties I have yet examined, that 
some error must have been committed in 
his proceedings. In all probability the 
error arose in his employing rectified spirit 
for separating the principles from one an- 
ON THE SOURCES AND COMPOSITION OF GAMBOGE. 
other; because rectified spirit, in dissoly- 3 
ing the resin, takes up also a considerable : 
part of the gum. The same objection is — 
applicable to the analysis of Braconnot, - 
though he has obtained more nearly the. 1 
true proportions of the principles. | 
The best solvent for separating the resin 
of Pipe Gamboge is sulphuric ether. When 
agitated with the powder, a lively orange- 
red solution is obtained, which becomes - 
Gamboge-yellow by dilution, and continues 
to show this tint when very greatly diluted, F 
proving the exceeding intensity of the co- —— 
lour. On distilling off the greater part of — 
the ether, and then driving away what re- 
mains by heating the residue in an open 
porcelain cup, a very beautiful, brittle re- 
sin is obtained, which has in thin layers a 
deep orange-colour and complete transpa- 
rency, and in thicker masses a cherry-red 
tint, so dark as to produce almost complete 
opacity, and which possesses in fine powder 
a lively Gamboge-yellow hue. It is re- 
markable that the very volatile fluid, sul- 
phuric ether, adheres with great force to 
this resin, insomuch as to be the source of 
much trouble, and even error in a quanti- 
tative analysis. The vapour-bath heat of 
212° F. I found insufficient to drive off so 
much ether as to leave the resin firm when 
cold; even at the temperature of 27, 
maintained by means of a muriate of lime 
bath for six hours, so large a quantity was 
retained, that the detached principles al- 
most always weighed conjunctly three per 
cent. more than the crude subject of ana- — 
lysis; nay, a heat of 400° subsequently 
applied for four hours by an oil-bath, por: 
I considered the highest temperature to 
safely applied to the resin, and which sent 
off copious bubbles of ethereal e 
still left a slight surplus of weight ın "ie 
separated principles when summed a 
The ether leaves, in the case of 2 
Gamboge, a flocculent matter, M i 
thoroughly exhausted by the repe what 
tion of the same fluid, coheres some" 
and acquires a very pale yellowish-W^ — 
i an 
1 Its colour is so intense that it co cili weight 
appreciable yellowness to ten thousand tii 
of spirit. 
mU TD By he ah ote ee ree ER IE ML mae sre ee T a T ENTER. 
