The new dispensatory: containing, I. The elements of pharmacy. II. The materia medica ... III. The preparations and compositions of the new London and Edinburgh pharmacopoeias / [William Lewis].

  • Lewis, William, 1708-1781
Date:
1785
Catalogue details

Licence: Public Domain Mark

Credit: The new dispensatory: containing, I. The elements of pharmacy. II. The materia medica ... III. The preparations and compositions of the new London and Edinburgh pharmacopoeias / [William Lewis]. Source: Wellcome Collection.

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    “ nature or operation of the faid oil. By fomewhat the like means <c any other Aillatitious oil may be transformed into a milk-white “ butter, and in like manner be mingled with water or any other <c liquor; which is of various ufe in medicine, and what I find u oftentimes very convenient and advantageous to be done.” (Grew, of mixture, chap. v. tnji. i. § 7.) This enquiry has lately been further profecuted, in the firft volume of the Medical Obser- vations published by a Society of phyficians in London; where a variety of experiments is related, of rendering oils both eflential and exprefl'ed, and different unctuous and refinous bodies. Soluble in water by the mediation of gurn. As oily and refinous fubftances are thus united to water by the means of gum, So gums may in like manner be united to Spirit of wine by the intervention of refins and eflential oils ; though the Spirit does not take up near So much of the gum, as water does of the oil or refill. Acid liquors, though they thicken pure oils or render them con- fident, do not impede the diflolution of gum, or of oils blended with gum. Alkaline Salts, on the contrary, both fixt and volatile, though they render pure oils difloluble in water, prevent the So- lution of gum, and of mixtures of gum and oil. If any pure gum be diffolved in water, the addition of any alkali will occaflon the gum to Separate, and fall to the bottom in a conflflent form : if any oily or refinous body was previoufly blended with the gum, this alfo Separates, and either Sinks to the bottom, or rifes to the top, according to its gravity. 8. Gum-refin. By gum-refin is underftood a mixture of gum and refin. Many vegetables contain mixtures of this kind, in which the component parts are So intimately united, with the interpofition perhaps of Some other matter, that the compound, in a pharmaceutical view, may be confidered as a diftindt kind of principle ; the whole mafs diffolving altnofl: equally in aqueous and in Spirituous liquors ; and the Solutions being not turbid or milky, like thofe of the grofler mixtures of gum and refin, but perfectly tranfparent. Such is the aftringent matter of biftort root, and the bitter matter of gentian. It were to be wiflied that we had Some particular name tor this kind of matter ; as the term gum-refin is appropriated to the grofler mixtures, in which the gummy and refinous parts are but loofely joined, and eafily Separable from one another. 9. Saline matter. Of the Saline juices of vegetables there are different kinds, which have hitherto been but little examined : the Sweet and acid ones arc the mod plentiful, and thofe which arc the moft known. ■8 Thefc