Researches upon the venom of the rattlesnake : with an investigation of the anatomy and physiology of the organs concerned / by S. Weir Mitchell.

  • Mitchell, S. Weir (Silas Weir), 1829-1914.
Date:
[1860]
Catalogue details

Licence: Public Domain Mark

Credit: Researches upon the venom of the rattlesnake : with an investigation of the anatomy and physiology of the organs concerned / by S. Weir Mitchell. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    the liquid. To this was now added a small amount of alcohol of 95 per cent. A cloud of a white and granular character was immediately seen at the lino where the alcohol and water met. Upon this an ounce and a half of the alcohol was added, when the lluid clouded throughout, and a white precipitate soon settled to the bot- tom. The supernatant alcohol and water being poured off and carefully evapo- rated at a temperature of 100° F., was examined toxicologically as usual. The evaporation was, of course, carried nearly to dryness, so as to avoid the risk ot killing the bird with alcohol. No poisonous results were observed, except in two . where the alcohol originally used proved to have been diluted with water, and to have acted as a partial solvent for the active material. It is necessary, on this account, to employ the strongest alcohol. 6th. The precipitate caused by the alcohol was washed repeatedly with succes- sive portions of that fluid, and allowed to settle. Then the last alcohol used to wash it was removed by pipette, and the precipitate spread on a plate to dry. On testing it toxicologically, it was found to be actively poisonous, giving rise, even when employed in minute amount, to all the local and general phenomena of Cro- talus poisoning. The material thus obtained, was of a pale yellowish tint when dried, and was perfectly neutral in reaction. It dissolved readily enough in water, cold or hot, and its aqueous solutions were troubled by alcohol. Its nitrogenous nature was established by its reaction with Millon's test of nitrate of mercury, and with the cupro-potassa test. As it appeared to me to be the active toxicological clement of the venom, I propose to distinguish it by the name of Orotaline. It seemed from the statements of those who quote Prince Bonaparte's method of analysis of viper-poison that he procured the essential principle, which he termed ichidnme, or mperine, in the following manner: The venom was treated with an excess of alcohol, and filtered; the residue on the filter being well washed with fresh portions of alcohol. The alcoholic solution was evaporated to dryness, and found to contain a coloring matter, and a small amount of an undetermined sub- stance, which, of course, was soluble in alcohol. The coagulurn was next washed, drop by drop, with cold water, so as to dissolve the echidnine, and leave the mucosine, become now insoluble from the influence of the alcohol. The echid- nine was separated from the aqueous solution by evaporation. In all essential particulars, echidnine and crotaline are alike. Upon repeating and varying M. Bonaparte's method of analysis, I found, however, some discrepancy of results. Thus, if to the venom of the Crotalus an excess of alcohol be added, a large precipitate occurs. In some instances, all of this precipitate was soluble in water; in other cases, a small proportion remained undissolved, behaving as ov-albumen would do after being coagulated by alcohol. Generally, as I have said, the bulk of the alcohol precipitate was soluble in water. The aqueous solution thus ob- tained could be coagulated by boiling, so as to throw down a harmless precipitate, and to leave above it a fluid still actively venomous, but representing in its dis- solved albuminoid substance but a small part of the nitrogenous precipitate caused by the alcohol in the first instance. In other words, the aqueous solution of the alcoholic precipitate behaved in the presence of heat exactly like the diluted venom itself.