Obs. The extract of the shops is usually prepared by exhausting the root by coction with water. The products of the first two of the above formulæ, when recent, have a faint and agreeable odour, and a sweet bitter taste; those of Nos. 4, 5, and 6, smell strongly of the recent root, have a pale and lively brownish-yellow colour, and a bitter acidulous taste, without any trace of sweetness; that of the last one is devoid of odour, and possesses a coffee-brown colour, and a sweetish, burnt taste, not much unlike a solution of burnt sugar. The medicinal virtue of this extract is greatest when the aroma and bitter taste of the recent root is well developed; and when sweet, its efficacy as a remedy is impaired. (Squire.)
Taraxacum root should be gathered during the winter months, when the quantity of the product is looked at; as then a given weight of the juice yields more extract; but in summer and autumn it possesses more bitterness and aroma. 4 lbs. of juice from roots gathered in November and December yielded 1 lb. of extract, while it took from 6 to 9 lbs. of juice from the root, gathered in spring or summer, to yield a like quantity. (Squire.) The herb yields by the evaporation of its expressed juice about 5% of extract. According to Mr Jacob Bell, the average yield of 1 cwt. of root is about 71⁄8 lbs. (‘Pharm Journ.,’ x, 446.)
Good extract of taraxacum should be wholly soluble in water.—Dose, 10 gr. to 1⁄2 dr.; as a resolvent, aperient, and tonic, in liver and stomach complaints, &c.
Extract of Tea. Syn. Extractum theæ, L. Prep. 1. From an infusion of any of the rougher kinds of black tea. Astringent. Has been recommended in diarrhœa; formed into pills.—Dose, 10 gr. to 1⁄2 dr. A hard, black-looking substance, smelling and tasting faintly of tea, is imported under the same name from China.
2. (Pidding’s.) The joint products of distillation and infusion combined. Proposed to be made in China, and exported as a condensed preparation of tea. (Essence of tea; Essentia theæ); to be used as a substitute for the leaves, in order to save the expense of freight, &c.
Extract of Thorn-Apple. See Extract of Stramonium.
Extract of Tobac′co. Syn. Extractum tabaci, E. Nicotianæ, L. Prep. 1. (Chippendale.) From decoction of tobacco. Proposed as an external application in neuralgia, &c.
2. (Alcoholic; Extractum tabaci alcoholicum, L.—Ph. Bor.) Tobacco leaves, 1 lb.; spirit (sp. gr. ·900), 2 lbs.; digest in a warm place for some days, express strongly, and again digest in a mixture of water and spirit (·900), of each, 1 lb., for 24 hours; again press out the liquor, and evaporate the strained and mixed liquors into a vapour bath, at a temperature not exceeding 167° Fahr.
Extract of Tor′mentil. Syn. Extractum tormentillæ, L. Prep. (Ph. Amst.) From the root of Potentilla Tormentilla, as EXTRACT OF HOPS—Ph. L. The Ph. Baden directs its preparation by displacement with cold water. Astringent and febrifuge.—Dose, 15 to 30 gr.; in diarrhœa. It was formerly regarded as a specific in syphilis. (Lindley.)
Extract of U′va Ur′si. See Extract of Whortleberry.