PHARMACEUTICAL EXTRACTS. 
177 
either from the mode of operation or during the evapora- 
tion, being avoided almost entirely. 
These extracts ought not to be employed excepting when 
specially directed by a medical man, and in no case should 
be substituted for those prepared in the ordinary way. 
Extract of Gentian. 
The observations of MM. Planche, Henry, and Caven- 
tou, and of M. Leconte, have shown the presence of the 
following substances in gentian: volatile odorous principle, 
gentisine, gluey matter, green oily matter, uncrystalliz- 
able sugar, gum, pectic acid, fawn-colored coloring mat- 
ter, organic acid, and bitter extractive matter. 
MM. Henry and Caventou, extracted from gentian a 
crystalline matter, which they considered, under the name 
of gentianine, as the bitter principle of gentian ; but this 
substance, gentisine, as has been shown by MM. Leconte 
and TrommsdorfF, is nothing more than a pale yellow co- 
loring matter, which crystallizes in long needles, tasteless 
and inodorous, which is mixed in the gentianine with va- 
riable proportions of the bitter principle and of fatty 
matter. 
It results from these facts, that the chemical nature of the 
bitter substance of gentian has still to be determined ; and, 
as will be seen, in the state in which it is now obtained, it 
exhibits the form of an unerystallizable extractive matter, 
very soluble in alcohol. 
Gentian, in coarse powder, 
Spirit, sp. gr. 0.S34, aa, q. s. 
The gentian is to be exhausted by Cadet's process, being 
treated three times successively with twice its weight of 
spirit. The liquors are put together and distilled over a 
water-bath to recover the spirit. The extract obtained is 
dissolved in distilled water, which takes up the bitter mat- 
ter, the sugar, and the free acid, and leaves the fatty mat- 
16* 
