Lectures on some of the applications of chemistry and mechanics to pathology and therapeutics / by H. Bence Jones.

Date:
1867
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on some of the applications of chemistry and mechanics to pathology and therapeutics / by H. Bence Jones. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    nerves of the heart; secondly, by an action on the muscular structure of the heart; thirdly, by contraction of the capil- laries in consequence of an action upon the sympathetic nerve; fourthly, by the reduction, quantitatively or qualita- tively, of the state of the blood. It is impossible at the end of this sketch to bring before you in any detail the progress of experimental inquiry abroad on some of these subjects. I can now do little more than give you the names of some of the substances and the kinds of action which they possess, and I must refer you to the original works for full details of the experiments that have been made except in the case of potash salts, which I shall take solely because it gives a good example of the progress that may be expected in therapeutical knowledge from scientific research. A medicine may act in only one, or in many, or in all the different ways that I have mentioned, and practically there is rarely a limited action, for the medicine if a crystalloid passes into every structure, and acts according to the properties of the substances with which it comes in contact. 1st. Of the medicines that act on the nerves of the heart in stopping its action, and thus making the circulation of the blood slower, strychnia is one of the most remarkable. When applied directly to the heart, it acts on the vagi nerves, and lessens the frequency of the heart's action; and it acts also on the ganglia. Nicotine acts on the vagi nerves alone. Conicine stops all the action in the peripheral nerves with- out affecting the muscular contractility. Digitaline first stimulates, and then paralyses the regulating nerves, and then stops the action of the heart. Quinine first stimulates, and then lessens, the action of the motor nerves of the heart, The difficulty of determining whether the retarded circula- tion depends upon an increase of the checking action of the nerves or upon a decrease of the motor action, whether in the heart itself or in the brain, is in many experiments exceed- ingly great; and, to add to the complication, a reflex action on the vagi nerves may produce the same effect as though