31. Lycopodium clavatum, Linn.—Common Club-Moss.
History.—The earliest writers by whom the medicinal qualities of this plant are distinctly referred to, are the herbalists (Brunsfels, Tragus, Cordus, &c.) of the 16th century.
Botany. Gen. Char.—Spore-cases unilocular, uniform or biform; the fariniferous ones subreniform, and bivalved; the globulifereus ones somewhat globose, 3-4-lobed, 3-4-valved. (Endlicher, Gen. Pl.)
Sp. Char.—Stem creeping; branches ascending; leaves linear-lanceolate, nerveless, terminating at the point in a bristle; spikes in pairs, stalked, cylindrical; bracts ovate, acuminate, premorse, toothed (Endl. Med. Planzen).
Roots of several strong scattered fibres. Stems procumbent, trailing, branching, leafy, several feet in length. Leaves crowded, curved upwards, linear-lanceolate, flat, ribless, smooth, deep green, partly serrated, tipped with a capillary point; those of the branches erect; the upper ones loosely dispersed. Spikes terminal, usually in pairs, rarely one, or three, densely beset with shortened, dilated, ovate, entire, long-pointed leaves or scales, in whose bosoms the small, sulphur-coloured capsules [thecae] are situated (Smith).
Hab.—Mountainous heaths and moors all over Europe. Indigenous. Perennial. July, August.
Description.—1. Sporulae Lycopodii. The powder sold in the shops under the name of lycopodium (pulvis, farina, pollen, seu semina lycopodii), witch-meal, or vegetable sulphur (sulphur vegetabile), consists of granules, usually regarded as sporules, but by some considered to be grains of pollen. In both their physical and chemical properties they resemble the latter. They are gathered towards the end of the summer, and are separated from the capsules, &c., by sifting.
Lycopodium is a very fine, odourless, tasteless, and very mobile powder, of a pale-yellow colour. It adheres to the fingers, but exhibits a repulsive force for water, and hence is with difficulty mixed with it. If strewed on this liquid it floats, and the hand may be dipped to the bottom without being moistened. If shaken up with water a portion of it sinks, but the greater part floats. With spirit of wine it is readily miscible. It is tinged brown by iodine. When thrown into the flame a candle it burns with great rapidity, producing an instantaneous flash of yellowish-white light.
When moistened by spirit of wine, or, still better, by oil of vitriol, and examined microscope, the granules are found to have the shape of tetrahedrons, with a convex base; or they may be described as spheroids, on a portion of whose surface there are three faces, or planes, uniting to form a three-sided pyramid. The faces appear to have been produced by the mutual pressure of the granules on each other, while in the spore-cases. The external membrane forms reticulated elevations, with intervening depressions or pits, giving a cellular appearance to the surface of the granules. The three-legged mark, at the union of the three planes, appears to be formed by a cleft in the membrane.
2. Herba Lycopodii (Herba musci clavati terrestris). This is odourless; at first sweetish, and then bitterish. Digested in water it yields a yellowish infusion; whose colour is deepened by sesquichloride of iron.
Composition.—Lycopodium sporules have been analyzed by Bucholz [Berlin. Jahrb. für d. Pharm. 1807, S. liv.; also L. Gmelin's Handb. d. Chem.] and by Cadet [Bull. de Pharm. t. iii. p. 31, 1811.]. The former chemist obtained the following results: Fat oil, 6.0; sugar, 3.0; mucilaginous extract, 1.5; and pollenin, 89.5. The substance called pollenin is, however, a complex organized body, and cannot be regarded as a proximate principle. By the action of caustic potash on lycopodium, Muspratt [Pharmaceutisches Central-Blatt für 1844, S. 904.] has shown that acetic acid is obtained.
The herb has not been analyzed. It appears to contain some acrid principle.
Adulteration.—As met with in the London shops, I have never found lycopodium (the sporules) adulterated.
The sporules of other species of Lycopodium are said to be sometimes substituted for those of L. clavatum: the microscope alone can detect the difference.
The pollen of some plants, as of Typha latifolia, and of some coniferous plants, is said to be sometimes substituted for the lycopodium sporules. The microscope readily distinguishes the substitution. The shape, the size, the character of the surface, and the cohesion or isolation of the grains, must be attended to in distinguishing them. The pollen of coniferous plants is also sometimes recognizable by its terebinthinate odour when rubbed in the hand: that of Typha latifolia is not so inflammable as genuine lycopodium meal.
Starch, talc, gypsum, chalk, boxwood powder, &c. &c., have been reported as adulterating substances. By throwing the suspected lycopodium on water, the mineral substances present would readily fall to the bottom, and might be detected by their appropriate chemical tests. Iodine and the microscope will detect starch. Boxwood powder has been separated from lycopodium by a fine sieve, which let the genuine sporules through, but retained the wooden particles.
Once I have seen lycopodium infected by a fungus, the matted mycelium of which had a slate colour, and a membranous or papery appearance.
Effects.—1. Of the sporules.—Applied externally, lycopodium acts as an absorbent and desiccant. Taken internally, it is reputed to possess demulcent, sedative, and diuretic properties; but these qualities are of doubtful existence.
2. Of the herb.—The herb appears to be endowed with some active properties. It acts as an emetic and cathartic, and is reputed to possess diuretic and emmenagogue qualities.
Uses.—1. Of the sporules.—Lycopodium is used both medicinally and pharmaceutically, as well as in the arts.
It is applied as a dusting powder to excoriated surfaces, especially the intertrigo of infants, and to parts affected with erysipelas, herpetic ulceration, eczema, &c. It is sometimes used in the form of ointment. In Poland, it is popularly employed as an external application in plica polonica. As an internal remedy, its powers are very doubtful. It has, however, been used by Wedelius and others [Murray, App. Med. vol. v.], and, in later times, by Hufeland, Jawandt, Rademacher, and Busser [Hufeland's Journal, Bd. ii. iv. and xxxvi.], in the retention of urine, and flatulent colic of infants; and in calculous complaints, hemorrhoids, gout, &c., of adults.
In pharmacy, it is used for enveloping pills and boluses. It serves both to isolate the pills and cover their taste.
But its principal use is at theatres, where it is employed for filling flash-boxes, and for producing artificial lightning. It is also used in pyrotechny. Gray says that females employed in delicate works use it to keep their hands free from sweat.
2. Of the herb.—This is rarely employed. It has been celebrated in the treatment of plica polonica, and, in consequence, has been called plicaria. It was employed in the form of decoction, both externally, as lotion and liniment, and internally [Vicat, Mémoire sur la Plique Polonoise (Murray, App. Med.).]. More recently it has been recommended by Dr. Rodewald [No. 16, Altenberger medicinische Zeitung, 1833. (Quoted by Dierbach, die neueste Entd. in d. Mat. Med. Bd. i S. 56, 1837.)] in retention of urine, from gravel, or pus [!], in atony of the muscular coat of the bladder, in weakness and relaxation of the inner membrane of the bladder, and as a diuretic. He states that he has used it for many years with great success.
Administration.—The sporules are administered internally in doses of from ten grains to a scruple, in the form of a mixture, or emulsion, made with syrup, mucilage, or yolk of egg. Externally, they are sometimes used in the form of ointment, composed of one drachm of lycopodium to an ounce of lard. The herb is administered in the form of decoction or infusion. Two up-heaped tablespoonfuls, with a pint of water, are to be boiled to one-half; and of this decoction a teacupful may be taken every ten minutes, or at longer intervals. In a more dilute state it may be drank as a tea.