Two lectures on the connection between the chemical properties and the physiological action of active substances; and the antagonism between the action of active substances. Delivered before the Royal College of Physicians, Edinburgh, on the 19th and 26th April, 1872 / by Thomas R. Fraser.

Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: Two lectures on the connection between the chemical properties and the physiological action of active substances; and the antagonism between the action of active substances. Delivered before the Royal College of Physicians, Edinburgh, on the 19th and 26th April, 1872 / by Thomas R. Fraser. 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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    potash in a remarkable manner paralyse the heart’s action, those of ammonia accelerate the circulation and produce spasms and general convulsions ; and, indeed, the general truth of the proposition, enun- ciated by Dr. Blake in 1839—to which, however, there are several ex- ceptions—that the salts of the same base have analogous actions, is now universally recognised. To the industry of this observer we are also indebted for another general proposition of great interest which bears upon this relationship. Several chemical substances possess the property of crystallising in the same form, and of replacing each other in crystalline compounds without alteration of the characteristic geo- metrical figure; in other words, they possess the property of iso- morphism. The physiological action of a large number of inorganic substances belonging to different isomorphic groups has been examined by Dr. Blake. The symptoms that were observed have led him to believe that, with a few exceptions, a striking analogy Exists between the isomorphic relations and the physiological action of the substances examined, an analogy to which he has given expression by the state- ment that “ isomorphous substances produce similar effects.” Substances which resemble each other in certain of their chemical pro- perties, possess smiilar degrees of poisonous activity.—Not only is there evidence to show that substances which resemble each other in their chemical properties may possess physiological actions of a simitar kind, but a correspondence may likewise be traced between certain of the chemical properties and the physiological activity, or poisonousness, of sub - stances. The combining or atomic weight of elementary bodiesforrasanim- portant character by which they may be distinguished from each other, and Dr. Rabuteau has published an extensive and valuable series of experiments, which he had undertaken for the purpose of determining whether any relationship exists between the atomic weight and physio- logical activity of elementary bodies. As a result of this investigation, he has found that the metals are more active physiologically according as their atomic weights are more elevated. For example, in reference to sodium, potassium, and thallium : sodium, with an atomic weight of 23, is almost inert; potassium, with an atomic weight of 39, is active in moderate doses; and thallium, with an atomic weight of 204, is a dangerous poison, nearly as poisonous, indeed, as lead, whose atomic weight is 207. On comparing magnesium, zinc, and cadmium, it is seen that magnesium, with an atomic weight of 24, is scarcely more active than sodium (23), for the salts of the former are prescribed in about the same doses as those of the latter; while zinc, with an atomic
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