Death by electric currents and by lightning : the Goulstonian lectures for 1913 delivered before the Royal College of Physicians of London / by A.J. Jex-Blake.

  • Jex-Blake, Arthur John, 1873-1957.
Date:
1913
Catalogue details

Licence: In copyright

Credit: Death by electric currents and by lightning : the Goulstonian lectures for 1913 delivered before the Royal College of Physicians of London / by A.J. Jex-Blake. 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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    Prevost and Battelli in 1899. The great merit of these authors was that they varied the electrical conditions of their experiments far more widely than any of their pre- decessors, and gave measurements not only of the voltages they employed but also of the amperages of the currents they passed through the various animals; they also registered the arterial blood pressure and the respiratory movements. Perusal of the published works of the vast majority of the other writers on this subject is apt to leave one with the impression that their authors were not particularly skilled physiologists or physicians in some instances, in others that they were not electrical experts or men of science. The work of Prevost and Battelli is both sound and brilliant, and shows a degree of com- petence in both physiological and electrical matters that inspires great confidence in their conclusions. They employed both alternating and continuous currents, and took great pains to ensure adequate electrical contacts between the terminals of their electric apparatus and the animal under experiment. In many cases one electrode was placed in the mouth, the other in the rectum; the resistance in different dogs with this arrangement varied between 250 and 400 ohms. Electrical contact was made for a few seconds or for a fraction of a second in different cases. An alternating current at five volts was painful to dogs when passed thus between mouth and rectum, but did not affect the respiration or the action of the heart. The current at a pressure of 10 volts in two seconds caused almost certain death, the ventricles of the heart being irremediably thrown into a state of fibrillation while the auricles continued to beat normally. Respira- tion stopped, owing to general muscular tetanus, during the passage of the current, beginning once more when it was cut off, but soon dying away again for want of irriga- tion of the respiratory centre in the bulb with blood, for after the current was turned on the blood pressure fell steadily away to nothing in about 15 seconds. Using metal electrodes covered with wetted cotton, suitably shaped and applied to the shaved chest-wall, they found the resistance of three dogs from one side of the chest to the other was about 300 ohms in each case, and these dogs were killed by alternating currents at 10 to 15 volts pres- sure. Fibrillary contractions of the heart muscle was found to be almost invariably fatal in dogs; life could be preserved for a time by massage of the heart and artificial respiration, but death ensued when these manipulations ceased, as the heart could not be induced to begin to beat spontaneously again. In the guinea-pig of medium size, however, massage of the fibrillatmg heart through the chest wall would sometimes restore the animal to life, the heart beginning its normal action again ; the resistance of the guinea-pigs as arranged for electrocution was from 700 to 900 ohms, and pressures of from 20 to 120 volts were found to be fatal by heart failure, as a rule. It was noted that in the case of the rabbit cardiac fibrillation tended to spontaneous recovery in most cases, and in the rat always.