Aconiti Folia - Aconite Leaves. - The fresh leaves and flowering tops of Aconitum Napellus. Gathered when about one-third of the flowers are expanded, from plants cultivated in Britain.

Characters. - Leaves smooth, palmate, divided into five deeply cut wedge-shaped segments; exciting slowly, when chewed, a sensation of tingling. Flowers numerous, irregular, deep blue, in dense racemes.

Aconiti Radix - Aconite Root. - The dried root of Aconitum Napellus. Imported from Germany, or cultivated in Britain. Collected in the winter or early spring before the leaves have appeared.

Characters. - Usually from one to three inches long, not thicker than the finger at the crown, tapering, blackish-brown, internally whitish. A minute portion, cautiously chewed, causes prolonged tingling and numbness.

Substance resembling Aconite Root: Armoracea. (See page 202.)

Composition. - The active constituent of aconite is aconitia or aconitin, C30H47NO7, an amorphous or crystalline alkaloid, forming salts with acids. The names of pseud-aconitin, napellin, nepallin, napalin, aconellin, etc., have been given to other more or less identical active principles obtained from the same plant or its botanical allies. They are combined with a peculiar acid, aconitic acid.

Preparations. A. Of the Leaves:

1. Extractum Aconiti

Extractum Aconiti. A green extract. Dose, 1 to 2 gr.

b. Of the Root:

1. Tinctura Aconiti

Tinctura Aconiti. 1 in 8 of spirit. Dose, 5 to 10 min.

2. Linimentum Aconiti

Linimentum Aconiti. 1, in 1 of spirit, with 1/20 camphor.

3. Aconitia, - An alkaloid ohtained from aconite root. Made (1) by dissolving the alcoholic extract of the powdered root in water; (2) Precipitating the impure aconitia by ammonia; (3) Extracting the dried precipitate with ether, dissolving in diluted sulphuric acid, again precipitating with ammonia, and purifying.

Characters. - See Composition. Not given internally.

Preparation. Unguentum Aconitiae. - 1 in 60.

Action And Uses. 1. Immediate Local Action And Uses

Externally. - Applied to the skin, or an exposed mucous membrane, aconite affects the terminations of the sensory nerves, causing tingling, followed by numbness, and lowering the sensibility of touch and temperature. It is, therefore, used to relieve pain due to disorder of the peripheral nerves, especially certain forms of neuralgia, and acute and chronic rheumatism. The aconitia ointment must be employed with caution.

Internally. - Aconite and aconitia cause an intensely acrid sensation on the tongue, followed by persistent tingling and numbness. A sense of warmth, pain, and sickness follow its admission to the stomach in full doses.

2. Action On The Blood

Aconitia enters the blood, and thence finds its way to the tissues.

3. Specific Action And Uses

Medicinal doses of aconite, taken in close succession, reduce the frequency, force, and tension of the pulse; flush and moisten the skin; and increase the amount of urine. Larger doses cause a sense of illness and muscular weakness; "creeping," "tingling," "numb" sensations generally, but especially on the lips, face, and extremities, ending in anaesthesia; and disturbances of vision, hearing, and consciousness. On analysis, it is found that the heart is briefly accelerated, and then reduced in frequency through the nerves; its force is then reduced, by direct action on the nervo-muscular structures; and finally the cardiac action becomes more frequent, irregular, and more and more feeble, tending to cease in diastole. The blood pressure falls continuously, partly from cardiac, partly from vaso-motor depression. Respiration is slowed and deepened, with spasmodic irregularity of rhythm, and finally is arrested after poisonous quantities. The skin is stimulated, perspiration becoming abundant. The kidneys are also stimulated, the fluids and solids of the urine being increased in amount. The temperature falls steadily. The muscular weakness appears to be primarily due to depression of the motor-nerve endings; but this condition extends to the cord. The brain itself is not directly affected, and even in cases of poisoning by aconite, consciousness is preserved almost to the end. The sensory nerves are probably paralysed from their periphery inwards by the internal, as by the external, administration of the drug.

Such being the specific action of aconite, its use is obviously indicated in the treatment of two conditions, namely, fever and pain. The cardio-vaseular excitement, the dry skin, the high temperature, and the scanty secretions of fever, will all be relieved by this drug. For this purpose the tincture is given in small and closely repeated doses, say 1 minim in water every 15, 20, or 30 minutes, the effect being watched. Acute tonsillitis, bronchitis, pleurisy, and febrile conditions attending other local inflammations, have been treated with aconite, the effect being to control the urgent symptoms, relieve the distress of the patient, and even to cut short the disease. Some of the symptoms of scarlatina and measles may be similarly alleviated. The powerfully depressant action of aconite on the circulation altogether forbids its use as an antipyretic in heart disease, and suggests caution in its employment in all cases.

In neuralgia and other painful affections connected with the nerves and muscles, aconite may be given internally instead of being locally applied; facial neuralgia with spasm (tic-douloureux) particularly being relieved by it. In these cases, also, the tincture should be given in minim doses, repeated three or four times in an hour, and the effect watched.

4. Remote Local Action And Uses

Aconite is probably excreted by the kidneys, and, as we have already seen, increases the activity of their secretion. The stimulation of the sweat-glands and the occasional appearance of an eruption suggest that it also leaves the body by the skin.

Podopliylli Radix - Podophyllum Root. - The dried rhizome of Podophyllum peltatuni. Imported from North America.

Characters. - In pieces of variable length, about two lines thick, mostly wrinkled longitudinally, dark reddish-brown externally, whitish within, breaking with a short fracture; accompanied with pale brown rootlets. Powder yellowish-grey, sweetish in odour, bitterish, subacrid and nauseous in taste.

Composition. - The active principle of the rhizome is the resin, which is really a compound of several resinous bodies.

Preparation. 1. Podophylli Resina. - Resin of Podophyllin.

Source. - Made by extracting with spirit, and precipitating in acidulated water.

Characters. - A pale greenish-brown, amorphous powder, soluble in rectified spirit and in ammonia.

Dose. - 1/4 to 1 gr.

Action And Uses

Externally, podophyllin possesses no local action; but if applied to a wound, it enters the blood and exerts its specific effect as a purgative.

Internally, podophyllin causes a bitter acrid taste, salivation, irritation of the stomach, nausea, colic, and after ten or twelve hours a free watery motion. This purgative effect appears to be due to stimulation both of the muscular coat and of the glands of the intestine, as well as to increase of the biliary flow.

Podophyllin is used entirely as a purgative. One-grain doses are given to produce free evacuation of the bowels in severe constipation or portal congestion. A dose of 1/6 to 1/4 grain may be employed as an ingredient of habitual laxative pills. It is a useful cholagogue when mercurials are contra-indicated. Podophyllin must not be given alone, on account of its griping tendency, but combined with a carminative such as hyoscyamus, belladonna, or cannabis indica. The comparative slowness of its action must also be remembered.