A reversed action of the vagus on the mammalian heart / by H.H. Dale, P.P. Laidlaw, and C.T. Symons.

  • Dale, Henry H. (Henry Hallett), 1875-1968.
Date:
[1910?]
Catalogue details

Licence: Public Domain Mark

Credit: A reversed action of the vagus on the mammalian heart / by H.H. Dale, P.P. Laidlaw, and C.T. Symons. Source: Wellcome Collection.

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    chiys’ degeneration the complete phenomenon was obtained, delayed inhibition and re-acceleration during the succeeding stimulus being produced in the characteristic manner. (Fig. 8.) In another case, in which degeneration had proceeded for four days, stimulation of the degenerated nerve produced neither inhibition nor acceleration, before or after the injection of a small dose of nicotine: nor did stimulation of the divided nerve produce any trace of re-acceleration when applied during a period of delayed inhibition, succeeding stimulation of the sound nerve of the opposite side (Fig. 9). Fig. 9. Cat. Paraldehyde. Eight vagus cut 4 days previously. A. Stimulation of right vagus, coil at 8 cm. B. ) i left ,, ,, 11 cm. C. j * right „ 5 cm. D. n left ,, ,, 11 cm. An exceptional result, to which reference has already been made, may conveniently be mentioned here. In one cat only the right vagus, 19 days after section, produced on stimulation a marked acceleration of the heart-beat (Fig. 10). Unfortunately the nerve was not cut high in the neck ; but even with the comparatively short peripheral portion available it was easy to satisfy ourselves that the acceleration effect increased as the electrodes were shifted towards the heart. The acceleration, moreover, was only obtained from any portion of the nerve with comparatively strong stimulating shocks. (Secondary coil at 10 to 8 cm. from the primary.) We attribute this result, therefore, like those of Schif f and Arloing, to the presence of recurrent fibres from the sympathetic ganglia. No sound medullated fibres could be