Experiments and observations upon the circulation in the snapping turtle, Chelonura serpentina : with especial reference to the pressure of the blood in the arteries and veins / by S. Weir Mitchell.

  • Mitchell, S. Weir (Silas Weir), 1829-1914.
Date:
1862
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Licence: Public Domain Mark

Credit: Experiments and observations upon the circulation in the snapping turtle, Chelonura serpentina : with especial reference to the pressure of the blood in the arteries and veins / 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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    ON THE CIRCULATION IN THE SNAPPING TURTLE. Since the experiments of Hales in 1731, and the later and more accurate researches of Poiseuille, a number of observers have studied the blood-pressures in various vertebrate animals, among which may be mentioned the horse, dog, sheep, cat, rabbit, and bird. So far as I can discover, the only observations of this nature upon cold-blooded vertebrata were made by Volkmann, who experimented upon frogs and fresh-water fishes. No other similar examination of blood-pressures appears to have been made, and up to the present date no one has studied the subject in connection with reptiles of any kind. The object of this memoir is to exhibit the results of a series of researches upon the blood-pressure in one of the most vigorous members of this class, the Ghelonura serpen- tina, and thus to fill an important gap in our knowledge of hsemometry. The reptile in question is admirably suited for this purpose. It is strong, active, singularly tenacious of life, and may be procured easily of any weight up to twenty-five or thirty pounds. Inhabiting the waters of many of the streams and mill-dams in the Middle States, it may be readily had in excellent condition during the spring and summer, and for all purposes of physiological and toxicological research, may be made use of whenever it is desirable to replace the frog by an animal of greater bulk and superior tenacity of life. The Snapping Turtles used in the following researches were brought from Havre de Grace on the Susquehanna river, and from the lower part of the State of Delaware, care being taken that only such were employed as had been captured by hand (dug out of the mud), rather than such as had been taken by the hook and line. As I have alluded to the great strength and tenacious vitality of these creatures, it may be well to make some brief statement of a more distinct nature as to the extent to which they are endowed with these qualities. A Snapper weighing twenty-seven and a half pounds was fastened by its tail to a ring,