General therapeutics and materia medica (Volume 2).

  • Dunglison, Robley, 1798-1869.
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: General therapeutics and materia medica (Volume 2). 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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    means of directly adding to the healthy tone of the system, in the mode described ; or, in particular conditions of the economy, other substances — belonging to different classes of therapeutical agents — may exert a tonic effect indirectly. Jn this way, blood-letting, cathar- tics, emetics, &c, may be indirect tonics. In the state of apparent debility, which accompanies febrile or other irritation, and in that in which the stomach or intestinal canal is loaded, and the nervous system oppressed and depressed, a remedy, which obviates these conditions, will remove the debilitant effects of such conditions, and prove tonic. When, however, we use the term tonic abstractedly, we never apply it to those indirect agents. It has been a question, occasionally agitated by therapeutists, whether there be any such thing in nature as a real tonic ; or, in other words, whether any remedial agent can, by virtue of properties inherent in it, communicate tone where tone is deficient. It would appear, that no such properties are possessed by any agent; or, in other words, that no principle is infused into an asthenic organ or tissue, which can give strength to it. The whole effect is exerted, directly or indirectly, on the nerves of the stomach, whence it is distributed, by means of the nerves, to every part of the system. It is probable, too, that some of the articles of the class are absorbed, and act upon the organism through the altered character of the blood in the capillary blood-vessels. Such, it has been conceived, is the modus operandi of the preparations of iron in chlorosis and other affections. Some tonics, again, are insoluble, and pass, apparently unaltered, through the digestive tube, appearing to exert their influ- ence like certain condiments, which contain no nutriment, but place the chylopoietic organs in a condition for deriving a larger amount of nutriment from alimentary matters taken along with them than they would otherwise have been able to separate. When a tonic is administered in disease, its speedy operation is not to be expected. This is one of the essential points of difference between tonics and excitants proper. The effects—as already re- marked — are gradually, and almost insensibly exhibited ; and they afford as good specimens of the action of what have been termed alteratives as any that could be selected. They produce no sensible evacuation. Under their employment, the appetite gradually im- proves ; the impressibility of the nervous system — often induced by long protracted indisposition, or by a rapid reduction of the vital forces, as in acute diseases—lessens ; the action of the circulatory system assumes the healthy standard ; the general feeling exhibits itself buoyant and elastic ; and the muscular powers, under the im- proved nervous influx, resume their wonted energy ; but al] this denotes only a restoration to the healthy standard; hence, the great use of tonics in convalescence ; but if administered in conditions of the system in which they cannot be expected to do good, they are devoid of the injurious consequences, that may follow the undue use of excitants proper, and their administration may be arrested at any 2*