OBSERVATIONS ON AMYGD ALINE. 
197 
Several species of the genus Prunus have been known to 
yield hydrocyanic acid when treated in a particular manner; 
and under the impression that all plants that yield this acid 
by distillation with water contain amygdaline, the following 
researches were entered upon. 
A quantity of the bark of the Prunus Virginiana was 
treated with boiling absolute alcohol, until every thing soluble 
in that menstruum was removed, and the alcoholic liquid fil- 
tered and evaporated to dryness. The extract obtained, 
amounted to nine per cent, of the bark employed, and had a 
reddish brown color. When the marc, remaining from the 
the alcoholic treatment, is moistened with water, no evidence 
is given of hydrocyanic odor, nor is the result more successful 
when the extract and marc are moistened together. But 
when the former is mixed with a solution of emulsine, that 
odor is immediately perceptible, and then, if the mixture 
be distilled, oil of wild cherry bark, (hyduret of benzule) 
and hydrocyanic acid are obtained; thus proving the existence 
of a principle in wild cherry bark which acts as amygda^ 
line, and of a decomposing agent, which, like emulsine, is 
rendered inert by ebullition. 
The alcoholic extract when treated with boiling water is 
nearly all dissolved, the insoluble portion being principally 
resin. 
If to this aqueous solution sub-acetate of lead be added, 
until it ceases to produce a precipitate, and a current of 
hydrosulphuric acid be passed through it, until all the lead is 
precipitated, and the liquid filtered and boiled to expel the excess 
of gas, we obtain a colorless, inodorous solution, which, when 
mixed with solution of emulsine, emits a hydrocyanic odor. 
If to this mixture a protosalt of iron be added, and then 
ammonia followed by hydrochloric acid, the blue color of Prus- 
sian blue is made evident. When the colorless solution above 
mentioned is saturated with potassa and then heated, ammonia 
is evolved. One can readily ascertain if the liquid is saturated, 
by adding to a portion of it some emulsine, when, if it be not, 
the characteristic odor is developed. When the potassa is 
VOL iv. — NO. III. 26 
