THE PSYCHO-GALVANIC REFLEX: A PHARMACOLOGICAL STUDY OF THE PERIPHERAL MECHANISM

The psycho-galvanic reflex is a decrease in the electrical resistance of the skin which occurs in response to a wide variety of stimuli. The physio-logical basis of this autonomic measure, known also as the galvanic skin response or electro-dermal response, has not yet been fully elucidated. There are two principal theories accounting for the phenomenon. The vascular theory, proposed by Fire (1888) and elaborated by McDowall (1933), maintains that it is caused by a change in tone of the blood vessels of the skin. The second theory, with many more adherents, was advanced by Tarchanoff (1890), who suggested that it was due to changes in the secretory activity of the sweat glands. This was later modified to changes in th