_Herba Aconita_; _Aconite Leaves_; F. _Feuilles d’Aconit_; G.,
_Eisenhutkraut_, _Sturmhutkraut_.
=Botanical Origin=—_Aconitum Napellus_ L., see preceding article.
=History=—Aconite herb was introduced into medicine in 1762 by Störck
of Vienna; and was admitted into the London Pharmacopœia in 1788.
=Description=—The plant produces a stiff, upright, herbaceous, simple
stem, 3 to 4 feet high, clothed as to its upper half with spreading,
dark green leaves, which are paler on their under side. The leaves
are from 3 to 5 or more inches in length, nearly half consisting of
the channelled petiole. The blade, which has a roundish outline, is
divided down to the petiole into three principal segments, of which the
lateral are subdivided into two or even three, the lowest being smaller
and less regular than the others. The segments, which are trifid, are
finally cut into 2 to 5 strap-shaped pointed lobes. The leaves are
usually glabrous, and are deeply impressed on their upper side by
veins which run with but few branchings to the tip of every lobe. The
uppermost leaves are more simple than the lower, and gradually pass
into the bracts of the beautiful raceme of dull-blue helmet-shaped
flowers which crowns the stem.
The leaves have when bruised a herby smell; their taste is at first
mawkish but afterwards persistently burning.
=Chemical Composition=—The leaves contain aconitine in small proportion
and also aconitic acid,—the latter in combination with lime.
_Aconitic Acid_, C₁₆H₆O₆, discovered by Peschier in 1820 in somewhat
considerable quantity in the leaves of aconite, occurs also in those
of larkspur, and is identical with the _Equisetic Acid_ of Braconnot
and the _Citridic Acid_ of Baup.[45] It has been stated to be present
likewise in Adonis vernalis L. (Linderos, 1876,—10 per cent. of dried
leaves!) and in the sugar cane (Behr, 1877).
Schoonbroodt[46] (1867) on treating the extract with a mixture of
alcohol and ether, obtained acicular crystals, which he thought were
the so-called _Aconella_ of Smith. He further found that the distillate
of the plant was devoid of odour, but was acid, and had a burning
taste. By saturation with an alkali he obtained from it a crystalline
substance, soluble in water, and having a very acrid taste. Experiments
made about the same time by Groves,[47] a careful observer, led to
opposite results. He distilled on different occasions both fresh herb
and fresh roots, and obtained a _neutral_ distillate, smelling and
tasting strongly of the plant, but entirely devoid of acridity. Hence
he concluded that _A. Napellus_ contains no volatile acrid principle.
In an extract of aconite that has been long kept, the microscope
reveals crystals of aconitate of calcium, as well as of sal-ammoniac.
The leaves contain a small proportion of sugar, and a tannin striking
green with iron. When dried they yield on incineration 16·6 per cent.
of ash.
=Uses=—In Britain the leaves and small shoots are only used in the
fresh state, the flowering herb being purchased by the druggist in
order to prepare an inspissated juice,—_Extractum Aconiti_. This
preparation, which is considered rather uncertain in its action, is
occasionally prescribed for the relief of rheumatism, inflammatory and
febrile affections, neuralgia, and heart diseases.
[45] Gmelin, _Chemistry_, xi. (1857) 402.
[46] Wittstein’s _Vierteljahresschrift_, xviii. (1869) 82, also
_Jahresbericht_ of Wiggers and Husemann (1869) 12.
[47] _Pharm. Journ._ viii. (1867) 118.