Extractum Iridis (U. S. P.)—Extract of Iris.
SYNONYM: Extract of blue flag.
Preparation.—"Iris, in No. 60 powder, one thousand grammes (1000 Gm.) [2 lbs. av., 3 ozs., 120 grs.]; alcohol, a sufficient quantity. Moisten the powder with four hundred cubic centimeters (400 Cc.) [13 fl℥, 252♏] 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 three thousand cubic centimeters (3000 Cc.) [101 fl℥, 212♏] of tincture are obtained, or the iris is exhausted. Distill off the alcohol from the tincture by means of a water-bath, and evaporate the residue, on a water-bath, to a pilular consistence"—(U. S. P.).
Description, Medical Uses, and Dosage.—This is a dark-brown extract possessing the odor and taste of the drug. The alcoholic extract of blue flag is a valuable cathartic and alterative. In doses of from 1 to 5 grains or more, it will be found a useful purgative in cases of obstinate constipation, hepatic torpor, indigestion, amenorrhoea, etc As a laxative the dose should be smaller. In larger doses it will produce hydragogue results, and may be given with advantage in chronic pulmonary affections, dropsy, worms, etc. In doses to fall short of catharsis, it becomes a valuable alterative, and will be found especially useful in rheumatic diseases, scrofula, syphilis, etc., and will frequently cause ptyalism. A few grains of ginger or capsicum will prevent any harshness of action. As an alterative, the dose is from 1/4 to 1 grain 3 times a day (J. King).