Essence of Guaiac′um

Syn. Fluid extract of guaiacum ; E entia guaiac i , Extractum guaiac i fluidum , L. Prep. Recent guaiacum shavings, from which the dust has been sifted, 3 cwt., are exhausted by coction in water, as in the preparation of an extract, using as little of that fluid as is absolutely nece ary; the decoction is evaporated to exactly 1 3 ⁄ 4 gall.; it is next stirred until cold, to prevent the deposit of resinous matter, when it is put into a bottle, and spirit of wine, 5 pints, is added; the whole is then repeatedly agitated for a week, after which it is allowed to settle for 7 or 8 days, and the clear portion is decanted into another bottle. Obs. This preparation is frequently substituted for guaiacum shavings in the preparation of compound decoction of sarsaparilla. 1 pint of this e ence is considered equivalent to 19 lbs. of guaiacum in substance. See Decoction of Sarsaparilla (Comp.).