UNCONSCIOUSNESS PRODUCED BY ELECTRIC CURRENTS

¹ The Department of Physiology and the Department of Electrical Engineering, Sheffield University

Experiments are described in which cats and rabbits are rendered unconscious by the very brief application of an electric current to the head region. No permanent disability follows, and the animal appears to have no memory of the occurrence.

The current employed was a unidirectional one, interrupted between 10 and 400 times per sec.; frequencies above 50 per sec. were most effective. The optimum voltage varied with different frequencies.

Direct observation and photographs of the vessels of the cerebral cortex show that these vessels are constricted by the current used.

Stimulation of the cervical sympathetic nerves also produces constriction of the pial vessels, but stimulation of these nerves in the unanæsthetised cat does not produce unconsciousness.

Unconsciousness can be produced by the electric current in cats three weeks after removal of the superior cervical ganglion.

The cause of unconsciousness in the cases described is not cerebral anæmia.

The expenses of this research were partly defrayed by a grant from the Medical Research Council.