Practical therapeutics : considered chiefly with reference to articles of the materia medica / by Edward John Waring.

  • Waring, Edward John, 1819-1891.
Date:
1871
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Licence: Public Domain Mark

Credit: Practical therapeutics : considered chiefly with reference to articles of the materia medica / by Edward John Waring. 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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    family to which it belongs. A few examples will suffice. The order Sola- naceae comprises belladonna, stramonium, and tobacco, three powerful sedatives, and capsicum, an acrid stimulant; the order Liliaceae contains the aloe, a drastic purgative; the squill, an expectorant and emetic; and the common asparagus, an innocuous vegetable; and in the Cucurbitaceae we meet with Ecbalium officinarum, which yields elaterium, a powerful hydragogue, and the common cucumber and the melon, both innocent articles of diet. It should be farther observed, that manjT articles pos- sessing very similar medical properties, belong to widely different orders. It is only necessary to mention digitalis and tobacco, both powerful de- pressants, and in some points closely resembling each other in therapeutic action ; the former belongs to the order Scrophulariaceae, the latter to the Solanaceae. 2. Similarity in chemical composition has been suggested, as indicating a similarity in therapeutic action, but there is less reliance to be placed on this test than even on that of the botanical characters ; although in some instances, as for example, the strong mineral acids and the fixed alkalies, where there is a close chemical relation, very analogous effects on the S3stem are produced. But these should be regarded rather as the excep- tions to than as the supporters of the rule. The following is one out of many examples of chemical affinity and dissimilar therapeutic action : Citric Acid, a mild refrigerant, H3 C6 H. 07. H2 O. Gallic Acid, a powerful astringent, H3 C7 H:) 05. H2 O. 3. The sensible properties of medical substances have been suggested as a test of their therapeutic action ; but no confidence whatever is to be placed on this test, as may be shown by one example. Sulphate of mag- nesia, sulphate of zinc, and the crystals of oxalic acid, so closely resemble one another in external characters, that they have often been substituted by mistake, the one for the other; yet how different are their effects—the first is a purgative, the second an emetic, and the third a virulent poison. 4. Experiments upon animals.—Much stress has been laid on this method of ascertaining the effects of medicines, and applying the results so obtained, by analog}-, to the human frame. This mode of procedure is, however, open to many objections, and is rendered fallacious in many instances, in consequence not only of differences of the digestive organs, but of the organization of the nervous system. Take the horse, for ex- ample: as much as six ounces of tartar emetic have been given to horses, without producing any remarkable or permanent derangement of the prin- cipal functions; they will take very large quantities of arsenic with simply the effect of rendering them sleeker and fatter; and they have been known to eat as much as eight pounds of belladonna leaves without any ill conse- quence. The peculiar construction of the stomach or stomachs of the cow, and other animals of the order Kuminantia, renders any deductions drawn from medicines exhibited by mouth to them very little to be relied upon ; besides which, it is well known that some animals will eat with perfect impunity substances which prove poisonous to man.