Abstract
Experiments were devised for the purpose of studying some of the effects of quinidin on the normal dog and guinea-pig heart. The method employed was comparatively simple. Dogs were fully anesthetized with ether, except in one instance when anesthesia was secured by means of chlorbutanol and morphin. The right fore leg and left hind leg were shaved, and suitable electrodes applied and connected to the string galvanometer in the usual way. All experimental electrocardiograms were therefore derived from Lead II. The thorax was not opened in any case; no direct auricular contacts were employed, and all observations were conducted on the spontaneously beating heart. When observations on the vagi were desired, these nerves were isolated for a considerable distance in the neck, sectioned, and the peripheral end stimulated from the secondary coil of the ordinary inductorium. A signal in circuit with the primary coil marked the beginning and end of