COMPOSITION OF GAMBOGE. 
139 
grains. But its operation was certainly different in degree, 
the efiect being always less in the dose of five, or five and 
a half grains, than from the equivalent dose of seven grains 
of gamboge, although care was taken to administer both to 
the same individuals, and in identically the same circum- 
stances, so far as this condition could be secured. I was at 
first inclined to imagine that the diminution of effect might 
be owing to a partial change produced by the heat to which 
the resin had been exposed. But this idea was necessarily 
abandoned on subsequent proof being obtained that a higher 
heat of 400°, which is little short of that required to produce 
chemical disorganization of the resin, has no further deterio- 
rating influence. 
" But it may be asked, whether the acridity of Gamboge 
is a property of the resin itself, or of some principle united 
with pure resin, and concentrating in itself the whole 
active qualities of the drug. On this point, chemical analysis 
has not yet thrown any light; nor have I been able to add 
anything to what is already known. Certainly no decomposing 
agent hitherto applied has detached a peculiar active principle 
from the resin; and it further appears probable that the pro- 
cess of saponification, which might be expected to detach an 
active principle, if it really were present, not only has no such 
effect, but even, according to some Pharmacologists, alters 
materially the action of Gamboge. For it is stated that Gam- 
boge, converted into 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 
diuretic properties. If these arguments, however, seem to 
favour the opinion that the active principle is nothing else 
than the resin itself, it should at the same time be remember- 
ed 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 ve- 
getable productions, 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 inhe- 
