Galvanism

In medicine, galvanism refers to any form of medical treatment involving the application of pulses of electric current to body tissues provoking the contraction muscles that are stimulated by the electric current. This effect was named by Alessandro Volta after his contemporary, the scientist Luigi Galvani, who investigated the effect of electricity on dissected animals in the 1780's and 1790's. Galvani himself referred to the phenomenon as animal electricity, believing that he had discovered a distinct form of electricity.

Voltage effects on humans

Previously, Isaac Newton had theorized a link between the 'animal spirits' described in antiquity and the subtle electrical fluid hypothesized by physicists. Caldini and Fontana had realized that merely bringing an electrified rod within their close proximity would stimulate frogs. However, it was Galvani who determined that electricity was present within the animal itself. Based on his frog experiments he deduced that contractions were caused by the flow of electricity and when one occurred a nervo-electric fluid was conducted from the nerves to the muscle.

In an application of his theory of animal electricity in 1791, Luigi Galvani suggested that an electrical fluid emanates from the human brain. Identifying life with electricity that has an organic source, Johann Wilhelm Ritter followed by equating animal and metalic electricity. The analogy of the cerebral cortex with the galvanic battery was then pursued by Paul Traugott Meissner, who argued that blood in the lungs becomes electrically charged through breathing, transmits its charge up the nerves to the spinal cord and brain, is used by the brain to electrically control the will, and then carries the charge to the limbs.

By 1854 a treatise by Emil Huschke included a chapter entitled, "The brain, an electric organ." Thomas Edison believed there would be less resistance to electrocution if administered through the hands of the condemned than if passed through the calf and scull. His recommendation resulted in the mishandled execution of Charles McElvaine in 1892, after which the state of New York returned to using the calf and scull. In 1920 Edison told an interviewer, "I am working on the theory that our personality exists after what we call life leaves our present material bodies." He reasoned that there would be no value to the hereafter if we did not survive as unique individuals. According to Edison, we consist of "swarms" of extremely small "life units," so small they can pass through walls of stone.

The modern study of galvanic effects is called electrophysiology, the term galvanism being used only in historical contexts. However, people still speak of being 'galvanized into action'.