ON THE EXTRACT OF HEMLOCK. 
173 
The experiments made seem to indicate that rectified spirits 
(sp. gr. .838 at 62° Fah.) is a more eligible menstruum for hem- 
lock leaves than proof spirit (sp. gr. .920 at 62° Fah.), inasmuch 
as the mucilaginous and albuminous constituents of the leaves are 
quite insoluble in the stronger spirit, while conia, in the state in 
which it exists in the dried leaves, is perfectly soluble in it. 
A portion of hemlock leaves, dried in the manner ment'oned, 
was percolated with spirit (sp. gr. .838 at 62° Fah.) until the 
liquid passed colorless. On treating the residue with water, and 
evaporating the liquid, an extract was obtained, which gave no 
smell of conia when rubbed with potash, and had the characteris- 
tics of an inert mucilage. A portion of the tincture obtained as 
above was allowed to evaporate spontaneously, the residue was 
very small in proportion to the quantity of the tincture employed, 
and could scarcely be said to possess the characters of an extract, 
inasmuch as it consisted of a yellow oily-looking semi-fluid sub- 
stance of very disagreeable odor, mixed with a small quantity of 
chlorophylle. Another portion of the same tincture was distilled 
with a strong aqueous solution of potash; the distillate, which 
evolved the odor of conia strongly, was mixed with a little water 
and left at rest ; after a few hours, a thin oily-looking film, having 
an alkaline reaction, appeared on the surface. 
It has been before mentioned that the object of these experi- 
ments was to ascertain the best means of preparing the Pharmaco- 
poeia extract of hemlock, the means by which the most efficient 
extract could be obtained, and whether proof spirit or rectified spirit 
was the best menstruum for hemlock leaves. 
It is thought that the following answers may be deduced from 
the account of the experiments made — 
1st, That the best means of inspissating hemlock juice is to 
subject it, placed in shallow vessels, to the influence of a continu- 
ous current of warm dry air. 
2nd. That an extract, possessing greater activity in equal doses 
than that generally met with in commerce, may be obtained byre- 
moving the albumen and chlorophylle from the expressed juice be- 
fore evaporating it. Were this mode adopted, there would not be 
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