Veterinary medicines : their actions and uses with a copious appendix on the diseases of the domesticated animals / by Finlay Dun.

  • Dun, Finlay, 1830-1897
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: Veterinary medicines : their actions and uses with a copious appendix on the diseases of the domesticated animals / by Finlay Dun. Source: Wellcome Collection.

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    I. THE MANNER IN WHICH MEDICINES ESTABLISH THEIR ACTIONS. Some medicines, as demulcents, caustics, and astringents, have merely a local or topical action—soothing, irritating, cor- roding, or altering the animal tissues, but not extending their influence beyond the part to which they are first applied. Others, either with or without such a local effect, have a remote or indirect action on organs at a distance from the part with which they are first brought in contact. Medicines which act thus remotely or indirectly are thought to produce their effects in either or both of the two following ways:—(a) They are absorbed into the circulation, and carried by the blood to remote organs ; or, (b) The impression which they produce on the parts with which they are brought in contact, is transmitted along the nerves to other parts. This latter mode of operation is some- times called action by sympathy. (a.) The great majority of those medicines capable of solu- tion appear to act in the former of these two ways, being taken up by the blood-vessels from' the surface of the mucous mem- branes, skin, or other part to which they have been applied. Thus, most medicines given by the mouth, after having, if solid, undergone solution in the acid gastric juice, alkaline bile, or intestinal secretions, pass, by a process of endosmose, into the- capillary veins which ramify on the surface of the stomach and intestines, enter the general circulation by the mesenteric and portal vessels, and are thus carried to all parts of the body, altering, it may be, the nutritive processes of various organs and tissues, and being at length expelled through some of the excretory channels, as the skin, kidneys, or bowels. The rapidity with which most substances are thus absorbed and make the round of the circulation is almost incredible. Pro- fessor Ilering, of the Veterinary College, Stuttgardt, found that yellow prussiate of potash injected into one of the jugular veins of a horse appeared in the other in twenty-five seconds, and was exhaled from the mucous and serous membranes in a few mi- nutes ; and also that chloride of barium injected into the jugular
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