JAL'AP (Sp. jalapai. A well-known purga tive medicine. It is the root of 4,011111a Jalapa, a plant of the natural order convolvulacex. It is found in Mexico, at an elevation of about 6000 feet above the level of the sea, in the neighbor hood of the town of Jalapa or Jalapa, from which its name is derived. It is a perennial twining plant, with large flowers and a turnip like root, varying from the size of a hazel-nut to that of a man's fist. The roots when fresh are white and fleshy, and abound in a milky juice. They are prepared for the market by drying. Jalap was long erroneously referred to other plants, among them Mirabilig Jalapa, known in flower-gardens as marvel of Peru.
Jalap seems to have been first introduced info England as a medicine about 1609.
The dried roots are brown and wrinkled ex ternally, and of a deep yellowish-gray color in ternally; their odor is faint and disagreeable and their taste is nauseous. The active ingredi
ent is the resinous portion, which contains con volvulin. Jalap resin may be distinguished from common resin by its insolubility in volatile oils. Jalap is a valuable cathartic, but is seldom given alone. It is an ingredient of the compound cathartic pill of the United States Pharmacopceia. Its purgative action is increased by the addition of a little ealomel, and its hydragogue action by hitartrate of potash, while its tendency to pro duce griping is obviated by the addition of a little ginger. In the form of compound jalap powder, which consists of one part of powdered jalap, two parts of bitartrate of potash, and a little ginger, it is of great service in some kinds of dropsy, in consequence of its hydragogue action.