Extractum Jalapae (U. S. P.)—Extract of Jalap.
Preparation.—"Jalap, in No. 60 powder, one thousand grammes (1000 Gm.) [2 lbs. av., 3 ozs., 120 grs]; alcohol, a sufficient quantity. Moisten the powder with three hundred and fifty cubic centimeters (350 Cc.) [11 fl℥, 401♏] of alcohol, and pack it firmly in a cylindrical percolator; then add enough alcohol to saturate the powder and leave a stratum above it. When the liquid begins to drop from the percolator, close the lower orifice, and, having closely covered the percolator, macerate for 48 hours. Then allow the percolation to proceed, gradually adding alcohol until the jalap is exhausted. Reserve the first nine hundred cubic centimeters (900 Cc.) [30 fl℥, 308♏] of the percolate. Distill off the alcohol from the remainder by means of a water-bath, and add the residue to the reserved portion, and evaporate to a pilular consistence"—(U. S. P.).
Description, Medical Uses, and Dosage.—The use of water in the preparation of this extract has been abandoned, since it was learned that it extracted none of the active constituents of the drugs. Moreover, it increased the bulk by dissolving inert matter, and rendered the extract more liable to become hygroscopic, and consequently to harden. Extract of jalap is a deep-brown, tenacious extract. It is cathartic in doses of from 10 to 20 grains, but is seldom used alone, being generally added to pills to increase their laxative or cathartic effect.