Report of experiments on the action of the heart / by C.W. Pennock and E.M. Moore.

  • Pennock, C. W. (Caspar Wistar), 1799-1867.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Report of experiments on the action of the heart / by C.W. Pennock and E.M. Moore. 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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    which is synchronous with the ventricular diastole; or to detail the succession more accurately, we have, 1st, the systole of the ventricles occupying one-half of the whole time, during which systole the auricle dilates ; 2d, immediately at the termination of the systole, the auricle contracts, and the ventricle dilates syn- chronously, occupying one-fourth of the whole time; 3d, the state of repose follows, in which the ventricle is full, occupying the remaining time. Dr. Pennock is of the opinion, that the auri- cular contraction occupied rather less time than the period of re- pose. Dr. Moore coincides with this opinion, except in not consi- dering the emptying of the auricles, during the diastole of the ventricles, the result of active auricular contraction, but of simple distention, relieved by the diastole of the ventricle, and thinks he perceives a contraction of the auricle at the termination of repose, immediately preceding the ventricular systole. The first sound, impulse, and ventricular systole, were synchronous. There was, however, an appreciable difference between the contraction of the ventricles, and the pulse, increasing as the distance from the heart was greater. The pulse varied from eighty-four to ninety-six, becoming irregular when the artificial respiration was omitted or too rapid. The heart pulsated two hours after opening of the chest. Experiment 2d. Present, Drs. Hardy, Pennock, and Moore. A ram, about a year old, whose pulse was irregular, but seventy-eight per mi- nute, was selected for the experiment, on account of the slowness of the heart's pulsation, which facilitates the analysis both of the sounds and motion. Sensation was destroyed by blows upon the head, as in the preceding experiment, and the chest opened as be- fore, but the heart beat feebly and irregularly, being congested, and expelling but a small portion of its contents. The sounds were feeble over the right ventricle, (not observed over the left,)