On the rhythm of the mammalian heart / by John A. McWilliam.

  • McWilliam, John A.
Date:
[1888]
Catalogue details

Licence: Public Domain Mark

Credit: On the rhythm of the mammalian heart / by John A. McWilliam. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    [From the Journal of Physiology. Vol. IX. Nos. 2 <i' 3.] ON THE RHYTHM OF THE MAMMALIAN HEART. By JOHN A. Me WILLI AM, M.D., Professor of the Institute of Medicine in the University of Aberdeen. (Plates III. IV.) (From the Physiological Laboratory of the University of Aberdeen.) The following investigation was conducted on the hearts of various mammals—cats, dogs, rabbits, hedgehogs, guinea-pigs, and rats. The cat was the animal usually employed, and the statements contained in this paper are all to be regarded as applicable to the heart of that animal, unless where otherwise specified. The experiments were performed (1) partly on the excised heart— sometimes with an artificial circulation kept up, and sometimes not— and (2) partly on the heart in situ. In the latter case, the animal was anaesthetized (usually with chloroform) and secured on a Czermak’s holder, means being taken to maintain the temperature as far as possible. Artificial respiration was employed and the chest was laid open; in some cases the pericardial sac was left intact, but in most of my experiments it was opened and the heart fully exposed. In some cases direct observation of the organ was kept up during the entire experiment; in many instances the action was graphically recorded in addition to frequent direct observation of the heart. Various arrangements were employed for registering the contractions of the auricles and ventricles. The auricular action was usually recorded by connecting one of the appendices by means of a thread with (1) a horizontal lever suspended by an elastic band and writing directly on a revolving cylinder or (2) with a receiving tambour which again communicated with a recording tambour. The ventricular beats were recorded in a variety of ways, most commonly by one or other of the following— (1) A light lever resting on the ventral surface of the ventricles and marking upon a smoked drum. The ventricles rested on a boat-shaped plate of vulcanite, which was slipped underneath them and rigidly held in position. (2) A float resting upon the ventricular surface and commurii- 12 nr. ix.