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SELECTED ARTICLES. 
melts at 62°; and upon cooling, assumes such a consistence 
that it does not adhere to the lingers, and can be polished by 
the friction of the finger nail. Treated with alcohol, it appears 
to separate into two parts; one soluble, resembling cerine; the 
other insoluble, which appears to be myricine. 
The fixed oil is in every respect analogous to other fatty 
substances. It is fluid, and thickens rapidly, in the same way as 
drying oils; its colour is greenish; its smell is that of gentian; 
it has no taste. It is insoluble in water, and in alcohol at 30°, 
but is readily dissolved by ether, and alcohol at 40°. These 
characteristics induce me to conclude, that the glue of gentian 
is a mixture of fixed oil, wax, and caoutchouc. 
The glue is readily obtained by treating dry gentian with 
pure ether, and removing the yellow crystals and oil with 
alcohol at 40°. 
Bitter Principle of Gentian. 
The time was not at my disposal to follow out completely 
the research, as regards the bitter principle of gentian. As it 
results from the experiments which have been reported upon 
the action of solvents, that the alcoholic extract is that which 
presents the bitter matter less connected with other extractive 
principles, gum and sugar, it w^as from this extract that I 
endeavoured to obtain it. 
By treating the alcoholic extract of gentian with cold water, 
there are obtained, on the one hand, flocculi, composed of 
gentisin, resin, and a fixed oil, which can be deprived com- 
pletely, by washing, of the bitter principle with which they 
are united in a state of mixture. There is obtained, on the 
other hand, a liquid of extreme bitterness, which determinately 
reddens litmus. By precipitating it with the subacetate of 
lead, two different products are obtained. The plumbic pre- 
cipitate holds in combination the substance to which the solu- 
tion of the principles of gentian owes its acidity. It can be 
separated by sulphuretted hydrogen. I have not, as yet, suffi- 
ciently studied its properties. The liquid which has furnished 
the deposition of lead, retains the bitter principle. By precipi- 
