ON THE EXTRACT OF RH A.TANF. 
269 
4th. By infusing one pound of rhatany in four pounds of 
hot water, Bouilay obtained seventeen drachms of extract, of 
which thirteen and a half drachms are soluble in cold water. 
5th. Finally, by lixiviating rhatany in powder with cold 
water, without previous maceration, so as to obtain four parts 
of product, it produces about fifteen drachms, or about eleven 
per cent, of dry extract, only one-fifteenth of which was in- 
soluble. 
From the foregoing remarks, it is evident that the use of 
boiling water as a menstruum is inexpedient, for two reasons. 
It dissolves matter contained in the root which is insoluble in 
cold water, viz., apotheme ; and it renders part of the soluble 
astringent matter insoluble and inert. 
Guibourt* has advanced the theory that the astringent co- 
loring principle is held in solution by the action of the free 
acid and gum in the juice of the plant, while the lignin and 
starch remain insoluble. When the dry root is treated by 
infusion, the lignin is not changed, nor is the starch dissolved, 
merely the dried juice of the root is liquified; which is the 
reason that the infusion produces an extract almost entirely 
soluble in water. By boiling the root the starch is dissolved, 
and combines with the astringent substance to form a com- 
pound soluble in boiling water but insoluble in cold, and the 
extract is thus increased in quantity at the expense of its 
quality 
These views of Guibourt, admitting his premises to be cor- 
rect, account very satisfactorily for the changes which occur 
during the ebullition of rhatany in water; but the analyses of 
this root prove that it contains very little fecula ; and Gmelin 
did not find any; hence there cannot be enough to account 
for the large quantity of insoluble matter obtained by boiling. 
The existence of an insoluble substance in the root, naturally, 
as proved by the action of cold alcohol which extracts it, will 
account for a large portion of the insoluble matter found in 
the extract produced from the decoction ; yet the fact, that 
* Pharmacopee Raisonee, p. 141. Edit. 3d, 
