Notes of three lectures on the physiological action of strychnia / delivered by George Harley.

  • Harley, George, 1829-1896.
Date:
[1856]
Catalogue details

Licence: Public Domain Mark

Credit: Notes of three lectures on the physiological action of strychnia / delivered by George Harley. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ing will ensue, how delicate the tests are, (both frogs became tetanic in less than ten minutes). A third frog became tetanic with only -jrnnr of a grain. In order to apply either the physiological or the colour-test to strychnia, we must first have the substance in a pure state. If, therefore, we wish to test for its presence in the digestive canal, tissues, or blood, we must first seek to separate the strychnine by a chemical process. The method I adopt, and which appears to me desirable from the ease and rapidity with which it can be applied, I shall now demonstrate to you in analyzing the blood of the dog killed with ^ of a grain. We take the blood from the heart and large vessels, mix it with twice its bulk of distilled water, coagulate by boiling, and acidify it with a few drops of acetic acid The acid is added for two reasons:— first, to ensure the complete coagulation of the albuminous compounds; secondly, to retain the strychnine which had been introduced into the blood as an acetate, in that state, or, if changed into another salt, to retransform it into an acetate. Our next point is to decolorize the blood; and that can be most rapidly and most effectually done by filtering it, as is now done, through crystals of sulphate of soda,—(this idea, as well as that of decolorizing the blood by boiling it with sulphate of soda, belongs to Professor Bernard,)—or through animal char- coal. The clear filtrate is now to be concentrated, and the strychnine precipitated by the addition of potash, (which, by combining with the acetic acid, sets the strychnia free.) The strychnine is next to be collected on a filter, washed, and re- dissolved by acetic acid. When thus purified, the physiological test is to be applied in the manner already pointed out. In the blood of the dog poisoned by ^ of a grain of acetate of strychnine, none of the poison was detected in the blood. Since the foregoing notes were in the hands of the printer, I have made several experiments, and found the following im- portant results:— 1. Value of the physiological test.—Into the lungs of a very small frog was injected a solution, containing only tvIisq °f a grain of the acetate of strychnine, (equal to about lHooo of the POSTSCRIPT.