240 
present, not only has no such effect, but 
even, according to some Pharmacologists, 
lters materially the action of Gamboge. 
For it is stated that Gamboge, converted in- 
to a soap by the action of an alkali, ceases 
to be purgative; so that a dose of twenty 
grains in this form has none of the usual 
effect, and on the other hand acquires diu- 
retic properties. If these arguments, how- 
ever, seem to favour the opinion that the 
active principle is nothing else than the 
resin itself, it should at the same time be 
remembered as favouring the opposite 
view—that the greater part of pure resins 
are nearly or entirely inert ; and still more, 
that it has been proved in regard to the 
closely allied class of vegetable produc- 
tions, the fixed oils, comprising several 
acrid species, such as croton-oil, the oil of 
the physic-nut, and some other energetic 
purgative oils, that their activity is not in- 
herent in the simple oil, but resides in a 
peculiar volatile acid principle, which may 
be detached. 
2. Passing next to the Lump or Cake 
Gamboge, it must appear evident, that the 
composition of this variety will vary much 
according to its quality. At least from 
what has been said above of its commercial 
history, it must either vary much, or we 
must separate from this sort all the kinds 
often mixed with it, and vaguely known in 
trade by the name of Coarse Gamboge. 
The finer qualities of it, usually called 
Cake or Lump Gamboge by druggists, 
appear from what I have seen, t 
tolerably uniform. It is met with in 
much the same with that of Pipe Gamboge ; 
its taste and odour are the same; and it 
ON THE SOURCES AND COMPOSITION OF GAMBOGE. 
very readily forms, with the wet finger, : 
smooth, bright Gamboge-yellow emulsion. _ 
Possibly the finer sorts which approach 
Pipe Gamboge in price, may also more 3 
nearly resemble that variety in external Í 
characters than has been here laid down; | 
but I have not met with any such speci- — 
mens. True Pipe-Gamboge, however, it — 
must be remembered, is often met with in 
the form of cakes, owing to several pipes 
or cylinders having been firmly agglutinat- — 
ed while soft.! 5.3 
The chemical composition of Cake-Gam- _ 
boge is also materially different. It is not, 
like the Pipe variety, entirely dissolved by 
the successive action of the two solvents, — 
sulphuric ether and cold water. About - 
eleven per cent. of insoluble matter re- | 
mains, which in cold water subsides com- 
monly in two layers, the uppermost white, — 
and very finely pulverulent, the lower one — 
grayish, and rather flocculent. The former 
proved to be fecula, entirely soluble in — 
boiling water, and then giving an abundant 
blue precipitate with tincture of iodine—the 
latter quite insoluble in boiling water with 
even six hours of ebullition, burning en- 
tirely away, with the flame and odour : 
burning wood, and with a mere trace | 
earthy residue, and therefore kim 
woody fibre or lignin. The analysis 
two samples gave results nearly concord- 
ant, as follows. One hundred grains were 
used, and all visible fragments of wood 
were excluded. 
First. Second. . 
Resin, dried in oil-bath at ! 64.3 65.0 
Aubin; dria 260»... 90.7 p^ 
Fecula, dried at 212° ... 6.2 a 
Lignin, dried at 212° ... 4.4 ye" 
Moistare' so. 408%. -- eor 
Total....99.6 100.1 
the 
The proportion between the gum and 
è resin is here identically the average PO” 
1 Cake Gamboge boiled in fine powder, a 
forms an emulsion, which is rendered — Gaite. 
tincture of iodine; while an emulsion of Pipe ; 
boge, similarly prepared, merely become 
tawny. 
A deco E E 5. 1! 
s somewhat — — 
