Preparation.—"Gentian, in No. 30 powder, one thousand grammes (1000 Gm.) [2 lbs. av., 3 ozs., 1.20 grs.]; diluted alcohol, a sufficient quantity to make one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏]. Moisten the powder with three hundred and fifty cubic centimeters (350 Cc.) [11 fl℥, 401♏] of diluted alcohol, and pack it firmly in a cylindrical percolator; then add enough diluted 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 diluted alcohol, until the gentian is exhausted. Reserve the first eight hundred cubic centimeters (800 Cc.) [27 fl℥, 25♏] of the percolate. Distill off the alcohol from the remainder by means of a water-bath, and evaporate the residue to a soft extract; dissolve this in the reserved portion, and add enough diluted alcohol to make the fluid extract measure one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏]"—(U. S. P.).
Description, Medical Uses, and Dosage.—This extract has a dark reddish-brown color, is translucent and free from sediment, and transparent in thin strata. It possesses the taste and odor of gentian. Tonic, and may be given in doses of from 1/2 to 1 fluid drachm, which represent 1/2 to 1 drachm of gentian root. It may be variously combined with other agents to meet particular indications. For instance, should an aperient tonic, with antacid properties be desired, the following form may be used: Take of fluid extract of gentian, 2 fluid ounces; fluid extract of rhubarb, 2 fluid drachms; bicarbonate of potassium, 1 drachm; tincture of ginger, 2 fluid drachms. Mix. One fluid drachm of this mixture will be equal to about 40 grains of gentian, 6 of rhubarb, and 3 of bicarbonate of potassium. If a chalybeate tonic is desired, the following may be employed. Take of citrate of iron and quinine, 1 drachm; water, 6 fluid drachms; dissolve, and add fluid extract of gentian, 2 fluid ounces. A fluid drachm of this mixture will represent about 45 grains of gentian, and 3 grains of citrate of iron and quinine (Wm. Procter, Jr.). Dose, 1 to 10 grains.
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.