Origin and Properties

Though all the acrid species of Aconitum possess medicinal virtues, the Aconitum Napellus, common monkshood, or wolfsbane, is the only one now acknowledged by the U. States or British authorities. it is a perennial herb, from two to six or eight feet high, growing wild in the mountainous districts of central Europe, and cultivated both for medical and ornamental purposes. it is occasionally met with in our gardens, where it is valued for the beauty of its spikelike racemes of fine, purplish-blue flowers. All parts of the plant are acrid; but the leaves and root only are officinal.

Aconite Leaf. Aconite leaves are three or four inches in diameter, divided, almost down to the base, into from three to seven wedge-shaped segments, each of which has two or three lobes; the several lobes being cut, at their edges, into linear pointed teeth. They are somewhat rigid, of a deep green above, and light green beneath, and rather smooth and shining on both sides. When fresh, they have a feeble narcotic odour, most perceptible when they are bruised, and a taste at first bitterish, but becoming hot and acrid, with a remarkable sensation of tingling and numbness, which extends through the whole mouth and fauces, and sometimes lasts for hours. They inflame the mouth if long chewed. When dried, they retain their acrimony, though it is later developed in the mouth. Their virtues are impaired by long keeping.

Aconite Root. Aconite root is spindle-shaped, about as thick as a finger at the base, tapering to a point, three or four inches or more long, brownish externally, internally whitish and fleshy, with many long fleshy fibres or rootlets. Not unfrequently two roots are joined laterally at the base, one deep-brown, and the other lighter coloured and younger. The taste is at first sweetish, afterwards acrid like that of the leaves, but stronger. The root shrinks in drying, but retains its acrimony, the degree of which may be considered as the measure of efficiency, as regards both the root and leaves. The root is much stronger medicinally than the leaves; their relative strength being, according to Messrs. Hirtz and Kopp, as 25 to 1. (Ann. de Thérap., 1862, p. 21.)

Active Principle of Aconite. The virtues of aconite reside chiefly if not exclusively in a peculiar organic alkaloid, which has been variously denominated aconitin, aconitina, and aconitia. I prefer the last name. As this principle is isolated for medical use, it will be particularly described among the preparations. Another alkaloid is said to have been discovered in it, for which the name of napellina (napellia) has been proposed (Am. Journ. of Pharm., xxx. 399); and Messrs. T. and H. Smith, of Edinburgh, have recently made known the existence of a third, which they name aconella, and which bears a close resemblance in properties to narcotina, and has little effect on the system. The former of these two alkaloids is not well known as to its effects; but it probably resembles aconitia, though much weaker. (E. Hottot, Ann. de Thérap., 1864, p. 44.) The plant contains also, but in very small proportion, a volatile principle, to which some have been disposed to ascribe, though erroneously, its acrid properties. it is probably the source of the slight odour of the leaves.

1. Effects Upon The System

Two elaborate monographs have been published on the subject of aconite, one by Dr. Alexander Fleming, of Cork, in the year 1845, and the other more recently by Professor Schroff, of Vienna, to the former of which I am especially indebted for many of the facts stated in the following account of the action of the medicine. Some valuable observations were also made by the late Dr. Pereira on its physiological action.

In general terms, aconite may be said to be locally irritant, and, in its general operation, directly sedative to the nervous system and the circulation, while it occasionally acts as a diaphoretic or diuretic.

Applied to the skin, it first occasions a feeling of heat, which is soon followed by prickling or tingling sensations, with numbness. in the mouth it gives rise more speedily and strongly to the same sensations, which are extended also to the fauces. When applied to the eye, it is said by most observers to cause contraction of the pupil; but Professor Schroff states that it produces the opposite effect of dilatation, when used in sufficient quantity. Both observations are probably correct; contraction being the result of its immediate operation, while the dilatation occurs when it has been employed so largely, or so long, as to exert its benumbing influence on the nervous centres which supply the circular fibres of the iris.

Given internally in medicinal doses, so as to bring the system moderately under its influence, it causes a feeling of warmth in the epigastrium, and a general glow, which may be ascribed to its first excitant action upon the mucous membrane of the throat and stomach, extended by sympathy over the body. A brief acceleration of the pulse, which sometimes takes place, may be referred to the same cause. Nausea is often also produced, but seldom vomiting, from the doses mentioned. After a short time, the same mingled feelings of prickling, tingling, and numbness, which it causes in the surface of application, are experienced at the ends of the fingers, in the lips, and perhaps elsewhere, together with a sense of muscular weakness; while the pulse is reduced in frequency and force, and the number of respirations correspondingly diminished. According to Storck the perspiration and urine are also increased; and Schroff states that, in sufficient quantity, it causes an extraordinary augmentation of the latter secretion {Ed. Month. Journ., Oct. 1854, p. 370); but these effects are certainly not constant, as they have escaped the attention of many observers.

In larger doses, but still within medicinal limits, aconite produces much nausea and occasionally vomiting; the sensation of tingling and numbness is extended more or less over the whole body; headache, giddiness, dimness of vision, and mental confusion are sometimes experienced, especially if any exertion is made; the pulse is reduced occasionally as much as 15 or 16 strokes in the minute, and the respiration accordingly; and a general condition of debility is induced, which may continue for hours or even days.