Royle's manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia and other approved medicines / by John Harley.
- Harley, John, 1833-1921.
- Date:
- 1876
Licence: Public Domain Mark
Credit: Royle's manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia and other approved medicines / by John Harley. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
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![Thus opium, alcohol, and the general ansesthetics, act on the cerebro-spinal nervous system, producing more or less complete paralysis of this part of the body, as indicated by complete flaccidity of the muscular system, and a state of unconsciousness. Hemlock leaves the intelligence and sensory system intact, while it paralyses the motor system. Strychnia causes spasms of the voluntary muscles, and ergot contractions of the involmitary. Atropia stimu- lates the sympathetic nervous system. Hydrocyanic acid rapidly abolishes all the functions. 3. As to the Mode of Action.—How does opium produce sleep, strychnia tetanus, and prussic acid its swdftly fatal effects 1 What a commotion the of a grain of atropia produces in the body, untO the last trace is eliminated, and every atom passes out unchanged ! How does it bring about the great cardiac excitement, the parched tongue, and the dilated pupil? We can only answer, “by a stimu- lant action on the sympathetic nervous system, and a closure of certain blood-vessels.” But such an answer brings us only a ste]j nearer to the cause; for, gi’anting that all the effects observed result from stimulation of the sympathetic, we have still to learn how atropia stimulates the sympathetic. Such questions are the most recondite that, can be submitted to. observation and reflection ; for on their solution hinges that of the highest problem of all,—the origin and nature of life. Truly, the most complex phenomena which science presents to the chemist or the astronomer, are simpli- city itself when compared with the higher problems of therapeutical inquiry. The difficulties which beset the subject have always been a great discouragement to those who have been most fitted to grapple with them, while they have engendered indifference in the general mass of medical men. Still, the facts which patient observation is accumidating are sufficiently numerous and to the point, to ^ve encouragement to all, and to prepare the way for simple intelligible theories. Many suggestions of this kind will be found in the fol- lowing pages ; for I have felt that if I may take my own wants as representing in any degree those of my readers, much good may be done by fixing the attention on reasonable explanations when we cannot direct it to positive facts. In considering the mode of action of a drug, we have first to ascertain how it obtains entrance into the blood (absorption) and exit from it (elimination). In a word, we have to consider it in reference to osmose, or to the passage of fluids through membranes. As a rapidly flowing liquid, and on account of its high specific gravity (1050), which is ^eater than that of any of the fluids of the body, and of its alkalimty, the blood is in a perfect condition for promoting the ingress of soluble matters of all kinds into the blood-vessels; while it is prevented, by its coUoidal qualities, from passing out of its containing vessels; and this accounts for the rapid absorption of fluids into the blood. But m the case of a large number of chemical salts,—such, for example, as chloride of calcium (which see), this must not be regarded as a mere mechanical process. In the elucidation of this subject the following](https://iiif.wellcomecollection.org/image/b21302911_0016.jp2/full/800%2C/0/default.jpg)
