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Show JALAP BINDWEED. 111 of Charlestown, ‘and flourishes in our own stoves. When recent, the root is white and lactescent; but it is brought to us in thin transverse slices, which are covered with a blackish wrinkled bark, and are of a dark gray colour internally, marked with darker or blackish stripes. It has a nauseous smell and taste; and when swallowed it affects the throat with a sense of heat, and occasions a plentiful discharge of saliva. When powdered it has a yellowish gray colour. Such pieces. should be chosen as are most compact, hard, weighty, dark-coloured, and abound most with dark circular striae and shining points; the light, whitish, friable worm-eaten pieces must be rejected. Slices of briony root are said to be sometimes mixed with those of jalap; but these may be easily distinguished by their whiter colour, and Jess compact texture. Neuman got from 7680 parts, 2480 alcoholic, and then by water 1200; and inversely, 2160 watery, besides 360 which precipitated during the evaporation, and 1440 alcoholic: the tincture extracted from 7680 parts, gave, by precipitation with water, 1920, JALAP BINDWEED. CONVOLVULUS JALAPA. MEDICAL USES. Class V. Pentandria. Essent. GEN. Cuar. Order ¥. Monogynia. Leaves ovate, subcordate, villose underneath. ——— ne DESCRIPTION. I uis plant has thick, fleshy, radish-like roots, full of a milky Juice; the stalks are numerous, twining for support, andrising to about ten or twelve feet; the leaves vary, being heart-shaped, angular, oblong, or pointed, smooth, and stand alternately upon long footstalks ; the flowers are usually two, on forked peduncles, bell-shaped, entire, plicate, of a reddish colour on the outside, and of a dark purple within. posed of five small oval leaves. The calyx is com- Each flower terminates ina wrinkled, roundish, pentagonal, umbilica l fruit, about the size of a pepper-corn, including a white kernel. HISTORY. Jalapis a climbing perennial species of convolvulus. hia Sinhabitant oa Fa It is an ean , ‘ of A Mexico and Vera Cruz, from which it was. first imported in 1710. It is now cultivated in the botanical gardcn Jalap in substance, taken in a dose of about half. a drachm, proves an effectual, and in general a safe purgative, performing its oflice mildly, seldom occasioning nausea or gripes; but in hypochondriacal disorders, and hot bilious temperaments, it gripes violently, if the jalap be good; but rarely takes due effect as a purge. An extract originally made by water purges almost universally, but weakly ; and at the same time has a considerable effect by urine: what remains after this process gripes violently. The pure resin, prepared by alcohol, occasions most violent gripings, and other distressing symptoms, but scarcely 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. Jalap contains both a gummy andresinous principle, an ounce yielding, according to Cartheuser, about half an ounce ofa gummy extract, and about two scruples of a resinous; neither |