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

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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$neither on the nature of the operation, nor of the materials, nor of the effect produced, but merely on the form in which the medicine is intended to he taken or applied. Thus, the diffolution of mercury in aquafortis is ranked among the chemical preparations ; while the very fame procefs, with the additional circumftance of uniting an unduous materia], which renders it, if any thing, {till more che- mical, is neverthelefs reckoned a galenical one, becaufe the pro- duct is ufed as an ointment. It cannot furely be fuppofed, that this is a juft divifion ; or that the fame procefs or preparation can be- come chemical or not chemical, according to the intention to which it is applied, or to the form in which the produdt is ufed. If vitriol of iron (that is, iron united with a certain acid) and any volatile alkaline fait, as that of hartfhorn or fal ammoniac, be put together into water, in due proportions, the pungent fmell of the volatile fait will be immediately fuppreffed ; this fait uniting with the acid of the vitriol into a new compound, while the iron is feparated and thrown out. This is undoubtedly a chemical effect:; and this effed will happen, wherever thofe two ingredients meet together in a moift ftate, whatever the form of the medicine be. It is obvious, therefore, that the galenical forms are by no means independent of chemiftry ; and that this fcience extends to mixtures of the moft fimple kind. The London college has very judicioufly rejeited this divifion; a divifion apparently derived from prejudice and fuperficial know- ledge, and which has been continued only in compliance with cuftom. Pharmacy, in its full extent, is no other than a branch of chemiftry, and the moft fimple pharmaceutical preparations are fo far chemical, as they have any dependence upon the properties or relations of the materials. Pharmacy, according to our definition, may be divided into theoretical and practical. Theoretical Pharmacy teaches the knowledge of the medicinal fubftances themfelves, their various O # # properties, qualities, and relations to one another, and their general effects on the human body : Practical pharmacy, the (kilful per- formance of the feveral procefi'es, or operations, by which they are adapted to particular ufes. What is here called theory is not to be underftood as confifting of fpecuiative truths, or philofophical inveftigations, calculated for explaining the phenomena, or teaching the rationale of the effeds produced. The theory of pharmacy is the direct refult of experi- ment and obfervation, or rather a general and comprehcnfive view of experiments and fads themfelves; it may be termed scientific pharmacy, in diftindion from mere manual labour. Scientific pharmacy includes all thofe fads which relate to—the^ redudion of medicinal fubftances into different forms, and the forms$