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Class V. PENTANDRIA. Order I. MONOGYNIA.
Capsules two-celled. Style one. Stigma two-lobed; the lobes
capitate. Ovary two-celled; cells two-seeded. Spe. Char. Stem twining. Leaves ovate, somewhat heart-shaped,
downy on the under side. Peduncles supporting one flower.
The root is perennial, large, ponderous, abounding with a milky juice, of an irregular, oval form and blackish color; the stalks are numerous, shrubby, slender, twisted, striated, rising from ten to twelve feet in height, and twining for support round the neighboring plants; the leaves are various, generally more or less heart-shaped, but often angular, or oblong and pointed, smooth, of a bright green color, and stand alternately upon long footstalks; the flowers stand upon two short branches, sending off two peduncles, each of which supports a single flower, which is large, bell-shaped, entire, plicated, externally of a reddish color, but of a dark purple within ; the calyx consists of five oval leaves; these are concave, somewhat indented at their points, and of a pale green color; the filaments are five, slender, short, and the anthers large and yellow; the style is shorter than the stamen; the stigma is round, and the germen oval.
This species of jalap is a native of South America, and flowers in August and September. It derived its name from the city of Xalapa, in the state of Vera Cruz, in the neighborhood of which it grows in
great abundance, at a height of more than six thousand feet above the ocean. It without doubt could be successfully cultivated, and be made a source of profit in the southern sections of the United States, were it fostered in those warm climates so congenial to the soil. It acquires great vigor and luxuriance, extending its stalks from fifteen to eighteen feet in length; the roots, also, both in appearance and medicinal powers, essentially differ from those cultivated in colder climes.
Medical Properties and Uscs. Jalap was first introduced into medical practice in Europe in the latter part of the sixteenth century, and from there into the United States, where it now ranks among the purgative medicines most extensively employed. The United States Dispensatory highly recommends it as being applicable in most cases where an active cathartic is required, and from its hydragogue powers is especially adapted to the treatment of dropsy. It is generally given with other medicines, which assist or qualify its operation. In dropsical complaints it is used in connection with the bitartrate of potassa ; also in the treatment of the hip disease and other scrofulous affections of the joints. With calomel it forms a cathartic compound, which has long been very popular with some physicians in the treatment of bilious fever, and other complaints attended with conjestion of the liver or portal circle. In over doses it sometimes produces dangerous symptoms, hypercatharsis, and will often purge when applied to a wound.
The dose of Jalap in powder is from fifteen to thirty grains; of the resin or alcoholic extract, which is chiefly used in Europe, and is now directed by the Edinburgh College, from four to eight grains ; the latter is usually given rubbed up with sugar, or in emulsion, by which its tendency to irritate painfully the mucous membrane of the bowels is thought to be in some measure obviated. Various species of the Jalap have at different periods been introduced into medical practice, all possessing more or less cathartic qualities.