34. Electric
cells
Towards
the end of the eighteenth century, Luigi Galvani, Professor of Anatomy at
Bologna University in Italy, published a book describing a series of
investigations he had made on the subject of "animal electricity". In
this book he described how a freshly dissected frog's leg could be thrown into
muscular convulsions, simply by connecting the foot and the exposed nerves
through a length of copper and iron wire (Fig. 34.1 ). It had been known for a
long time that the muscles of dead animals could be caused to contract by means
of an electric shock from a machine or Leyden jar, and therefore it was
suggested that some source of electricity might be responsible for the
contractions of the frog's leg.
Fig. 34, 1.
Galvani's experiment with a frog's leg
Galvani himself
was of the opinion that the muscle and nerve acted like a kind of charged
Leyden jar and that discharge took place when they were joined by the copper
and iron wires. His fellow countryman, Alessandro Volta, could not agree with
this but believed that the two dissimilar metals were more important than the
leg. Subsequently, Volta did some experiments to show that electricity was
produced when two different metals were separated by various non-animal liquids
and these practically settled the matter in his favour.
‘Ordinary Level Physics’
Abbott
Pg 402
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