Convolvulus Scammonia. Scammony.
Nat. Ord. — Convolvulaceae. Sex. Syst. — Pentandria Monogynia.
The Concrete Juice of the Root Gum Resin.
Description. — This plant has a perennial, fleshy, fusiform root, from three to five feet long, and from three to five inches in diameter, branching toward its lower extremity, covered with a light-gray epidermis, and abounding in a milky juice. The stems are annual, numerous, slender, round, smooth, branching, twining, very slightly angular near the ends, and extending from twelve to twenty feet upon the ground, or on neighboring plants. The leaves are on long petioles, alternate, sagittate, oblong, acute, entire, quite smooth, truncate and angular at the base, with acute spreading lobes, and of a bright-green color. The flowers are pale-yellow, and are placed in pairs, or three together upon solitary, axillary and round peduncles, which are nearly twice the length of the leaf. Sepals five, rather lax, smooth, ovate, repand, obtuse with a reflexed point, colored at the edge. Corolla, funnel-shaped, very much expanded, pale sulphur-yellow, thrice as long as the calyx, an inch or more in length ; limb entire, somewhat reflexed. Stamens five, erect, converging, thrice as short as the corolla. Ovary two-celled, four-seeded, supporting a slender style as long as the stamens, with two linear-cylindrical, erect, oblong, parallel, distant and white stigmas. Capsule two-celled, with small pyramidal seeds.
History. — Scammony plant is a native of Turkey, Syria, Greece, Persia, etc., and somewhat resembles the Convolvulus Panduratus. The officinal portion is the concrete juice of the root, the other parts of the plant yielding no milky juice whatever. It is collected in the month of June, at which time the earth is cleared away from about the root, which is obliquely cut across near its crown, and a shell, or other convenient receptacle is fixed under the most depending part of the slope, into which the milky juice gradually flows. This soon concretes under exposure to the air and evaporation, forming the gum-resin of commerce, Scammony ; of which but a few drachms are obtained from a single root. It is seldom had in a pure state, being more or less adulterated with flour, ashes, meal, chalk, sand, etc. It is imported directly from Smyrna, or from some of the Mediterranean ports. There were several varieties of scammony formerly known, as the Aleppo, Smyrna, and Montpelier, of which the first-named was the best, but, owing to the adulteration of the drag, it is impossible to keep up these distinctions any longer, and consequently the article is now recognized as genuine or factitious scammony.
Genuine Scammony, called pure or virgin Scammony, is ranked among the gum-resins, containing, however, but a small proportion of gum; it is in irregular pieces, often covered with a whitish-gray powder, compact, light, very brittle, and easily pulverizable ; with a somewhat conchoidal, shining grayish-green fracture, soon passing to dark greenish-black, and exhibiting under the microscope minute air-cells and numerous gray semi-transparent splinters. It exhales a strong, peculiar odor, especially if breathed upon, and has a feeble taste when chewed, succeeded by acridity in the back of the throat. Its powder is of a pale ash-gray color. It is nearly wholly soluble in boiling alcohol, and sulphuric ether takes up from 77 to 83 per cent, of it. With water it forms a smooth emulsion, which is not permanent. Alcohol, however, is its best solvent. Analysis has detected in it a large proportion of resin, from 77 to 83 per cent., and small quantities of gum, fiber, sand, starch and water ; the starch is an accidental ingredient, probably derived from the root.
As found in the shops, scammony is in compressed circular cakes, sometimes flat on both sides, at others convex on one side, about five or six inches in diameter, from half an inch to two inches thick, of a dark-ash or slate color, somewhat lighter internally, but darkening on exposure to the air, of a smell similar to that of the genuine article, as well as the taste ; it is easily pulverized, affording a light-gray powder, and when triturated with water forms a greenish milky emulsion. These cakes are often broken and met with in fragments, with a faintly shining roughish fracture, hard, heavy, exhibiting a finely porous structure, and sometimes slightly translucent at the edges. This kind of scammony is always more or less adulterated with carbonate of lime, guaiacum, cow-dung, starch, etc.
A factitious scammony called Montpelier Scammony is manufactured in the South of France from the expressed juice of the Cynanchum Monspeliacum mixed with various resins and other purgative substances. It has been sold as Smyrna scammony. It is in black, hard, compact, flat, semicircular cakes, about five or six inches in diameter, and half an inch or more in thickness, of a somewhat shining and resinous fracture, a weak, balsamic, disagreeable odor, and a very bitter nauseous taste. When rubbed with the moistened finger, it becomes dark-gray, unctuous and tenacious. It is more irritating and less purgative than the other varieties. There are several other kinds of scammony occasionally met with, but which may be detected by the proper tests.
Pure scammony may be known by being light, of a glistening almost resinous fracture if it be old and dry, friable, always of a brownish-gray color, and not subject to the results of the tests given below for detecting its adulterations. Sulphuric ether separates at least eighty per cent, of resin dried at 280°.
Pure scammony maybe obtained by boiling the finely-powdered article of commerce in successive portions of proof spirit, till the spirit ceases to dissolve anything ; filter, and distil the liquid until little but water passes over. Then pour away the watery solution from the resin at the bottom ; agitate the resin with successive portions of boiling water till it is well washed, and finally dry it at a temperature not exceeding 240°. This separates the active matter of scammony from its impurities, and is called the Extract of Scammony. It forms with unskimmed milk, a uniform emulsion, scarcely distinguished from rich milk itself.
The addition of carbonate of lime as an adulteration, may be detected by its effervescing with muriatic acid ; starch, may be known by the tincture of iodine forming a blue precipitate with an aqueous solution of the drug ; guaiacum, may be detected by an application of some of the tincture of the suspected article on the fresh-cut surface of a raw potato ; if guaiacum be present, it turns it quickly to a bright blue color.
Colophony may be detected in the resin of scammony, by the oil of turpentine, which dissolves it at common temperatures, leaving the scammony resin almost wholly unacted upon. But the best reagent for this purpose is sulphuric acid, which possesses the property of dissolving many resins, and of modifying, more or less, their composition. If a little of this acid be poured over colophony, it immediately, and by simple contact, develops an intense red color. The same acid, when poured over pure resin of scammony, produces, on the contrary, no immediate change ; it is only, after the lapse of some minutes, and with contact of the air, that it becomes colored, and then but slightly, the color being wine dregs. For this purpose, four or five grains of the resin may be placed into a glass or porcelain mortar ; and sixty or eighty grains of the sulphuric acid of commerce added. Upon rubbing it with the pestle, it will become red at once, if colophony be present. This method will detect the one-twentieth part of the adulteration.
Properties and Uses. — Scammony is a powerful, drastic cathartic, operating with harshness and griping. It was a favorite internal and external remedy with the Arabians. It does not appear to be poisonous even in large doses, but is seldom used alone, except in cases where a powerful impression upon the bowels is desired ; most commonly it is combined with other cathartics, whose action it promotes, while its own harshness is diminished. Scammony is usually given in the form of an emulsion with sugar or sweet almonds. But when triturated with milk it is considered a superior preparation, as follows : Seven grains of pure scammony to be gradually triturated with three ounces of unskimmed milk, to which a few grains of ginger may be added, forms a safe purgative. Another form of using this gum-resin, is that of biscuit. A paste is made of scammony one drachm ; Venice soap, five grains ; sugar nine grains ; biscuit in powder one ounce, and a few drops of water. Mix together, divide into two biscuits, and let them dry ; one biscuit acts energetically. The dose of powdered scammony is from five to fifteen grains ; of the pure resin, one half this quantity. Its use is always contra-indicated by intestinal inflammation.
Off. Prep. — Pilulae Podophyllini Compositae. Pilulae Gambogiae Compositae.