The elements of materia medica and therapeutics (Volume 1).

  • Pereira, Jonathan, 1804-1853.
Date:
1843
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Licence: Public Domain Mark

Credit: The elements of materia medica and therapeutics (Volume 1). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    y. By combining the basis with substances of a different value, and which do not exert any chemical influence upon it, but are found, by experience, to be capable of render- ing the stomach, or system, or any particular organ, more susceptible of its action: us when we combine Mercury with Antimony and Opium, to increase the activity of the former. II. To correct the operation of the basis, by obviating any unpleasant effects it might be likely to occasion, and which would pervert its intended action, and defeat the objects of its exhibi- tion. <t. By mechanically separating, or chemically neutralizing, the offending ingredient; as by digesting Cetraria Islandica in an alkaline solution, in order to remove the bitter prin- ciple, and to enable us to obtain a tasteless, but highly nutritious fecula. /3. By adding some substance capable of guarding the stomach or system against its de- leterious effects; as when we combine Aromatics with Drastics, to correct the griping qualities of the latter;—or Opium with Mercurials, to prevent the latter affecting the bowels. III. To obtain the joint operation of two or more medicines. a. By uniting those substances which are calculated to produce the same ultimate results, although by totally different modes of operation : as when we combine Digitalis and Potash to produce diuresis,—the first acting on the absorbents, the second on the se- creting vessels of the kidneys. fi. By combining medicines which have entirely different powers, and which are required to obviate different symptoms, or to answer different indications : as when we combine Opium and Purgatives in painter's colic,—the first to relieve the spasm, the second to evacuate the contents of the intestinal canal. IV. To obtain a new and active remedy not afforded by any single substance. a.. By combining medicines which excite different actions in the stomach and system, in consequence of which new or modified results are produced : as when we combine Opium (a narcotic) with Ipecacuanha (an emetic) to obtain a sudorific compound. 0. By combining substances which have the property of acting chemically upon each other; the result of which is, the formation of new compounds, or the decomposition of the original ingredients, and the development of their more active elements : as when solutions of Acetate of Lead and Sulphate of Zinc are mixed to procure a solution of the Acetate of Zinc: and when the Compound Iron Mixture of the Pharmacopoeia is prepared. y. By combining substances, between which no other chemical change is induced, than a diminution, or an increase, in the solubilities of the principles, which are the reposito- ries of their medicinal virtues : as when we combine Aloes with Soap, or an Alkaline Salt, to quicken their operation, and remove their tendency to irritate the rectum. V. To afford an eligible form. a.. By which the efficacy of the remedy is enhanced ; as in the preparation of Decoctions, Infusions, Tinctures, &c. /3. By which its aspect or flavour is rendered more agreeable; as when we exhibit medi- cines in a pilular form, or when we exhibit them in a state of effervescence. y. By which it is preserved from the spontaneous decomposition to which it is liable; as when we add some spirituous tincture to an infusion, (I. Organic peculiarities.—Vegetables have their medicinal properties conside- rably modified by the nature of the soil in which they grow, by climate, by cul- tivation, by anfe, and by the season of the year when gathered. e. Dose.—The modifications produced in the effects of medicines by differences of dose, are well seen in the case of Opium, Mercurials, and Turpentine. 2. Relating to the Organism.—Under this head are included several circum- stances, of which the most important are the following:— a. Age.—One of the most distinctive characters of organized beings is that of undergoing perpetual mutation during the whole period of their existence; thus constitiitin<r the phenomena of age. In order the better to appreciate these changes, the life of man has been portioned out into certain periods of ao-ea, as they have been termed, though as these pass imperceptibly into each other? there is no absolute or fixed distinction; and, consequently, the number of these periods Vol. I.—19 1