In the 1790s, the Italian Luigi Galvani carried out a series of electrical experiments that became known as galvanism. With a spark from an electrostatic generator, he produced a twitching movement in the muscles of a dead frog. As his research progressed, he was able to produce the same effect on a dog and expressed an interest in experimenting on a human. This is a rare first edition of notes by Galvani, detailing his experiments.
Earlier experiments in the 1760s had determined that muscular activity in the bodies of frogs could be caused externally. Galvani’s experiments in the 1780s led from the chance touching of a scalpel to the lumbar nerves of a frog at the same time a spark was caused by electrical apparatus. The combination produced convulsive contractions of the frog’s muscles. There may have been a completion of an electrical circuit or perhaps contact between the scalpel and another metal (the hook holding the frog’s body in position) generated enough electricity to stimulate the muscles. Galvani considered the possibility that the muscles retained some kind of innate electricity, a fluid within the nerves, which he described as ‘animal electricity’. His experiments led later to a medical treatment known as galvanism, in which nerves are stimulated by the application of an electrical charge.
THE EFFECTS OF ARTIFICIAL ELECTRICITY ON MUSCULAR MOTION
I dissected and prepared a frog, as in Fig. a, Tab. I, and placed it on a table, on which was an electrical machine, Fig. I, Tab. I, widely removed from its conductor and separated by no brief interval. When by chance one of those who were assisting me gently touched the point of a scalpel to the medial nerves, DD, of this frog, immediately all the muscles of the limbs seemed to be so contracted that they appeared to have fallen into violent convulsions. But another of the assistants, who was on hand when I did electrical experiments, seemed to observe that the same thing occurred whenever a spark was discharged from the conductor of the machine, (Fig. i, B).
… I was fired with incredible zeal and desire of having the same experience, and of bringing to light whatever might be concealed in the phenomenon. Therefore I myself also applied the point of a scalpel to one or other crural nerve at a time when one or other of those who were present elicited a spark. The phenomenon always occurred in the same manner: violent contraction in individual muscles of the limbs, just as if the prepared animal had been seized with tetanus, were induced at the same moment of time in which sparks were discharged.
But fearing lest these very motions arose rather from the contact of the point, which perchance acted as a stimulus, than from the spark, I again tested the same nerves in the same way in other frogs, and even more severely, but without any spark being elicited at that time by anyone; but no motions were seen at all. Hence it occurred to me that perhaps for the induction of the phenomenon both the contact of some body and the passage of a spark were simultaneously required. Wherefore I applied the edge of the scalpel again to the nerves and held it motionless, both at the time when a spark was being elicited and when the machine was perfectly quiet. But the phenomenon appeared only when the spark was produced.