DERIVATION.--Aconite is obtained from the root of aconitum napellus,
which grows in Northwestern North America, Europe and Asia in
mountainous regions, and cultivated in the United States for its
beautiful flowers.
PROPERTIES.--The fresh leaves have a faint narcotic odor, most sensible
when they are rubbed. Their taste is at first bitterish and herbaceous,
afterwards burning and acrid, with a feeling of numbness and tingling on
the inside of the lips, tongue and fauces, which is very durable,
lasting sometimes many hours. When long chewed they inflame the tongue.
The dried leaves have a similar taste, but the acrid impression
commences later. Their sensible properties and medical activity are
impaired by long keeping. They should be of a green color, and free from
mustiness. The root has a feeble earthy odor. Though sweetish at first,
it has afterwards the same effect as the leaves upon the mouth and
fauces. It shrinks much in drying and becomes darker, but does not lose
its acrimony. Those parcels, whether of leaves or roots, should always
be rejected which are destitute of this property. Aconite root is
officially described as being “slenderly conical, 4 to 10 cm. long, 10
to 20 mm. thick at the crown; occasionally split; longitudinally
wrinkled; dark brown and marked with coarse whitish root-scars; fracture
short, horny or mealy; internally whitish or light brown; the cambium
zone irregular and 5 to 7-angled; odor very slight; taste sweetish, soon
becoming acrid and developing a tingling sensation, followed by
numbness.”
Preparations of the leaves are not official in the U. S. P. The root is
five times stronger than the leaves.
CONSTITUENTS.--The alkaloid representing the action of the drug is
aconitine, which is precipitated by ammonia from an aqueous solution of
an alcoholic extract of the root of various species. It is a colorless,
crystalline or amorphous, gray powder, almost insoluble in water, and
soluble in 22 parts of alcohol, in 44 parts of ether and 1 part of
chloroform. Its salts are soluble in water. Aconitine or its solutions,
unless very dilute, are too poisonous to be tasted.
Commercial preparations vary in purity and strength, and since it is
extremely poisonous its internal administration is undesirable.
Pseudo-aconitine, aconitine and other alkaloids in combination with
aconitic acid have been obtained from aconite, but their identity and
chemistry are uncertain.
DOSE.--Horses and cattle, 3 to 20 grs.; sheep and pigs, 1 to 3 grs.;
dogs, ¹⁄₁₀ to ¹⁄₁₁ gr.