for private distribution to other scientists, one copy being sent to Alessandro Volta, professor of
physics at Pavia.
Fig. 1.2. The discovery of "animal electricity." When a spark was drawn from the electrical machine
(left) the frog's leg would twitch if a metal scalpel was touching the nerve to that leg. We now know
that the expanding and collapsing electric field induced a charge in the scalpel, which then stimulated
the nerve. Galvani however, apparently believed that the metal scalpel permitted the electricity in the
nerve to function. He embarked on a long series of experiments that today seem to have been going in
the wrong direction (see figure 1.3), but we must take into consideration the state of knowledge of
electricity at that time.
V
olta repeated and confirmed Galvani's observations, at first agreeing with his conclusions of
"animal electricity," but later he became convinced that the electricity was generated not by the nerve,
but by the two dissimilar metals in the circuit. Volta must have immediately realized that this was a
new kind of electricity being continually produced-a steady current, as opposed to the instantaneous
discharges from the friction machines of von Guericke. Volta immediately improved the apparatus,
constructing several types of bimetallic "piles" for the generation of continuous current. His
observations were published in the Philosophical Transactions of 1793 setting in motion both a major
advance in the knowledge of electricity, as well as a particularly strident controversy that was to
occupy the life sciences for the next century and a half. While Volta acknowledged his debt to Galvani,
he left no doubt that in his mind there simply was no electricity in living things-Galvani had simply
misinterpreted his findings.
Fig. 1.3. Galvani's demonstration of bimetallic generation of electricity. The vertebral column of the
ELECTROMAGNETISM & LIFE - 12