CHEMICAL HISTORY OF GENTIAN ROOT. 
337 
I have already shown that this gentianin can be deprived, 
by successive crystallizations, of all the bitter principle which it 
contains in the state of mixture; but as the w^ord gentianin has 
been for a long time employed to indicate the bitter principle 
of gentian, I have judged it proper not to employ it to desig- 
nate a substance entirely destitute of bitterness; although it 
be true to state, that it composes in a measure the gentianin of 
MM. Henry & Caventou. I propose, in consequence, the 
name of gentisin, which sufficiently recalls its origin, and 
which I derive from Gentis, King of Illyria, to whose memory 
the genus Gentiana has been consecrated. 
To procure their gentianin, MM. Henry & Caventou have 
employed ether, strong alcohol, weak alcohol, then water and 
magnesia, and finally ether ; they have even retaken the 
magnesian precipitate by oxalic acid. It is true, that ether, 
although imperfectly dissolving gentisin, removes from gen- 
tian all its yellow crystalline matter; but it is necessary 
to employ a considerable amount of ether to obtain a small 
quantity of product, and the substance is connected with 
glue, which requires several alcoholic solutions to be sepa- 
rated. 
This method is, therefore, long, difficult, and expensive. 
From among the solvents of gentisin, I have endeavoured to 
find one which would yield me a pure product by a method 
more prompt and more economical. Alcohol at 40°, at 35°, 
at 30°, and water with an alkali in solution, were successively 
employed, as well hot as cold; it is cold alcohol at 40°, which 
has affiDrded me most advantages. 
To prepare gentisin, I take coarsely powdered and dried 
gentian. I treat it by successive macerations in alcohol at 
40°, until it no longer becomes coloured. The liquids, being 
united and filtered, are submitted to distillation; the extract 
obtained is treated by water, which dissolves the bitter ex- 
tractive matter, the free acid, the sugar, and leaves under the 
form of white flocculi, the fatty matter in union with the 
gentisin. This precipitate is collected, washed, dried, and re- 
dissolved in boiling alcohol at 30°, which dissolves the yellow 
