JALAP, in botany and the materia medica, the root of a species of convolvulus or bind-weed. See CONVOLVULUS.
This root is brought to us in thin transverse slices from Xalapa, a province of New Spain. Such pieces should be chosen as are most compact, hard, weighty, dark-coloured, and abound most with circular striæ. Slices of bryony root are said to be sometimes mixed with jalap; but these may be easily distinguished by their whiter colour and less compact texture. Jalap has no smell, and very little taste upon the tongue; but when swallowed it affects the throat with a sense of heat, and occasions a plentiful discharge of saliva.—Taken in substance in a dose of about half a dram, (less or more according to the circumstances of the patient), in plethoric or cold phlegmatic habits, it proves an effectual and in general a safe purgative, performing its office mildly, seldom occasioning nausea or gripes which too frequently accompany the other strong cathartics. In hypochondriacal disorders, and hot bilious habits, it gripes violently if the jalap is good; but rarely takes due effect as a purge. An extract made by water purges almost universally, but weakly; and at the same time has a considerable effect by urine. The root remaining after this process, gripes violently. The pure resin prepared with spirit of wine occasions most violent gripings and other terrible symptoms, but scarce proves at all cathartic; triturated with sugar, or with almonds into the form of an emulsion, or dissolved in spirit and mixed with syrups, it purges plentifully in a small dose, without occasioning much disorder. The part of the jalap remaining after the separation of the resin yields to water an extract which has no effect as a cathartic, but operates powerfully by urine.—Hoffman particularly cautions against giving jalap to children; and assures us, that it will
Jamaica. will destroy appetite, weaken the body, and perhaps occasion even death: but herein he is contradicted by Geoffry; who observes, that children whose vessels are lax, and the food soft and lubricating, bear these kinds of medicines better than adults.—Certain it is, however, that jalap, when given to children, most frequently proves emetic as well as cathartic.