be so contracted that they seemed to have fallen into tonic
convulsions. Another of my assistants, who was making ready to
take up certain experiments in electricity with me, seemed to
notice that this happened only at the moment when a spark came
from the conductor of the machine. He was struck by the novelty
of the phenomenon, and immediately spoke to me about it, for I
was at the moment occupied with other things and mentally
preoccupied. I was at once tempted to repeat the experiment, so
as to make clear whatever might be obscure in it. For this
purpose I took up the scalpel and moved its point close to one
or the other of the crural nerves of the frog, while at the
same time one of my assistants elicited sparks from the
electric machine. The phenomenon happened exactly as before.
Strong contractions took place in every muscle of the limb, and
at the very moment when the sparks appeared, the animal was
seized as it were with tetanus.'

Following this original observation, Galvani made a great many
experiments on the effect of electric stimulus upon the nerves
of frogs and other animals. He found that the twitching of the
frog's muscles could be produced by atmospheric electricity,
both at the time of lightning and at other times when no
lightning was visible. During these investigations he observed
that when the legs of the frog were suspended from an iron
railing by a hook through the spinal cord, and when this hook
was of some other metal than iron, the muscles would twitch
whenever the feet touched the iron railing. He tried out a
number of pairs of metals, and found that when the nerve was
touched by one metal and the muscle or another point on the
nerve was touched by another metal and the two metals were then