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Mary
Bellis
Galvanism
During the 1790s, Italian physician Luigi Galvani demonstrated what we now
understand to be the electrical basis of nerve impulses when he made frog
muscles twitch by jolting them with a spark from an electrostatic machine.
Luigi Galvani
Luigi Galvani was born in Bologna, Papal States (Italy). He studied medicine
at the University of Bologna and after graduation was appointed lecturer in
anatomy at the University of Bologna and professor of obstetrics at the
Institute of Arts and Sciences. His early research began with his doctoral
thesis in comparative anatomy with a tendency toward physiology.
Following the acquisition of an electrostatic
machine (a device for making sparks) and a Leyden jar (a device used to store
static electricity), Luigi Galvani began experimenting with muscular
stimulation by electrical means. Through numerous observations and experiments
Luigi Galvani caused muscular contraction in a frog by touching its nerves
with electrostatically charged metal. Later, he was able to cause muscular
contraction by touching the nerve with different metals without a source of
electrostatic charge. He concluded that animal tissue contained an innate
vital force, which he termed "animal electricity." He believed this
to be a new form of electricity in addition to the "natural" form
that produced lightning and to the "artificial" form that is
produced by friction (i.e., static electricity). He also believed the brain
secreted an "electric fluid" and that the flow of this fluid through
the nerves provided a stimulus for the muscle fibers.
Scientific colleagues generally accepted
Galvani’s views; but Alessandro
Volta, a professor of physics, was not convinced. Volta demonstrated that
the electricity did not come from the animal tissue but was generated by the
contact of different metals, brass and iron, in a moist environment. However,
in another experiment, Galvani caused muscular contraction by touching the
exposed muscle of one frog with the nerve of another and thus established for
the first time that bioelectric forces exist within living tissue.
Galvani’s discoveries opened the way to new
research in the physiology of muscle and nerve and pioneered the subject of
electrophysiology -- the study of the connection between living organisms and
electricity. Continue
with >>> History of
Batteries
top photo
provided by National Library of Medicine
right photo provided by NASA |
Galvani's
Experiments Illustration of Italian physician Luigi Galvani's experiments,
in which he applied electricity to frogs legs; from his book De Viribus
Electricitatis in Motu Musculari (1792).
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