Conii Folia, B.P. Conium Leaves.
Conium or hemlock leaves are obtained from the hemlock, Conium maculatum, Linn. (N.O. Umbelliferae), a plant distributed throughout Europe and Great Britain. The fresh leaves and young branches are collected when the fruit is beginning to form. The leaves are much divided and quite glabrous, the ultimate divisions terminating in smooth, colourless points. They are attached by amplexicaul petioles to a smooth hollow stem, marked with purplish spots. The inflorescence is a compound umbel, provided with both general and partial involucres, the latter consisting of three short lanceolate bracts directed outwards. The fruits bear crenate ridges, and have a deeply grooved endosperm. The drug has a disagreeable odour of mice, which is accentuated by the addition of solution of potassium hydroxide. Conium leaves are liable to adulteration with the leaves of other indigenous umbelliferous plants, such as wild chervil, Anthriscus sylvestris, Hoffm., and fool's parsley, Aethusa Cynapium, Linn. Wild chervil is distinguished by its hairy leaves; fool's parsley by the absence of a general involucre of bracts, the bracts of the partial involucre being long and narrow, and the ultimate divisions of the leaves terminate in short brownish points.
Constituents.—The chief constituents of conium leaves are the alkaloids coniine (conine) and conhydrine; the stem contains about 0.06 per cent. of total alkaloids, the leaves about 0.18 per cent., and the flowers and flower-stalks about 0.24 per cent. Conium also contains methyl-coniine, ethyl-piperidine, and pseudo-conhydrine. Coniine is a highly toxic, colourless, oily liquid with a disagreeable mouse-like odour.
Action and Uses.—Fresh conium herb is employed in the preparation of Succus Conii, and of the green extract. Succus Conii is used internally for its sedative and antispasmodic properties (see Coniina). Externally, as Unguentum Conii, it is a soothing application to haemorrhoids and other painful or irritable conditions of the rectum and anus. For inhalation the addition of alkali to the juice is necessary to set free the alkaloid from its natural combination (see Vapor Coniinae). The green extract of conium is used in pill form and also in suppositories as a sedative. The latter may contain 30 centigrams (5 grains) in each, and require the same precaution in making as suppositories of other green extracts. Incompatible with alkalies, and preparations of conium should not be prescribed with alkalies except when intended for inhalation. In cases of poisoning by conium, the antidotes described under Coniina should be employed.
Dose.—1 to 5 decigrams (2 to 8 grains).
- Extractum Conii, B.P., 1885.—EXTRACT OF HEMLOCK.
- Press out the juice from bruised conium leaves, heat it to 54°, and strain through calico to remove the chlorophyll. Heat the strained liquor to 93°, remove the coagulated albumin by filtration, evaporate the filtrate to a thin syrup by the heat of a water-bath, add the previously separated chlorophyll, after passing it through a hair sieve, stir, and evaporate to a soft extract at a temperature not exceeding 60°. The alkaloidal content of this extract varies considerably, averaging about 0.4 per cent. It is used as a mild sedative and antispasmodic in pill form (see Pilula Conii Composita), and in suppositories, 30 centigrams (5 grains) in each, in place of Extractum Belladonnae. Dose.—½ to 2 ½ decigrams (1 to 4 grains).
- Pilula Conii Composita, B.P. 1885.—COMPOUND PILL OF HEMLOCK.
- Extract of hemlock, 5; ipecacuanha, in powder, 1; treacle, a sufficient quantity. Dose.—3 to 6 decigrams (5 to 10 grains).
- Succus Conii, B.P.—JUICE OF CONIUM. Syn.—Hemlock juice.
- Juice of conium is prepared by subjecting the bruised, fresh leaves and young branches of Conium maculatum, Linn., to pressure, adding to the expressed juice one-third its volume of alcohol, allowing the mixture to stand for seven days, and filtering. This juice varies considerably in strength, different samples yielding from 0.012 to 0.062 per cent. of total alkaloidal hydrochlorides. It is used chiefly to make Unguentum Conii and Vapor Coniinae. For both preparations the standardised liquid extract of conium fruit would be more suitable. Dose.—4 to 8 mils (1 to 2 fluid drachms).
- Unguentum Conii, B.P.—CONIUM OINTMENT. Syn.—Hemlock Ointment.
- Juice of conium, 200; hydrous wool fat, 75. Concentrate the juice of conium to 25 by evaporation on a water-bath, at a temperature not exceeding 60°; then incorporate the hydrous wool fat. A much more satisfactory preparation can be made by evaporating 200 of conium juice to 50, and mixing it with 50 of anhydrous wool fat. A preparation more constant in strength might be prepared from the standardised liquid extract of conium fruit. Conium ointment is applied to relieve the pain of haemorrhoids, cancer, and anal fissure.
- Vapor Coniinae, B.P., 1885.—CONIINE INHALATION.
- Juice of conium, 4; solution of potash, 1; distilled water, 8. Mix the juice of conium and solution of potash, and add the water. Quantity sufficient for one inhalation, 12 decimils (1.2 milliliters) (20 minims), which is placed on a sponge in a suitable apparatus so that the vapour of hot water passing over it can be inhaled. Coniine inhalation is used to relieve cough in bronchitis, whooping cough, etc.