Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

Electricitatis in Motu Muscidari" until 1791. In that work he laid down the proposition that there is a peculiar form or kind of electricity existing in all living animals, which he desig- nated as animal electricity. As to his famous discovery, by means of the contractions of the legs of a dead frog, he be- lieved that he merely excited and rendered sensible this native electricity by covering a nerve and a muscle with metallic con- ductors, but did not regard tbe latter as the real source of the electricity. In fact, Galvani based the explanation of the phe- nomena of muscle contractions on his neuro-electric theory. He assumed that all animals are endowed with an inherent electri- city, exactly appropriate to their economy, which nerve-electri- city, being secreted by the brain, resides mostly in the nerves, and by which it is communicated to every part of the body. The principal reservoirs of this electricity he considered to be in the fibres of the muscles, each of which he regarded as having two sides, i. e., opposite electric conditions. He believed, therefore, that when a muscle was willed to move, the nerves, aided by the brain, drew from the interior of the muscles some electricity ; then, by discharging this upon their surface, which he believed to be negative, they were made to contract or draw together, and thus produce the required change of position. Thus, then, Galvani was the first not only to stumble upon the manifestation of a new form of electricity by the frog twitch- ings, but to blindly demonstrate the existence of animal electri- city ; for he verily thought it was that only which produced the phenomena. Here were given to the world two stupendous truths, by a single little prophetic fact! When he touched the sciatic nerve of a frog with one kind of metal, and at the same time touched the muscles of the leg with another kind of metal, while the other ends of the two bits of metal were in contact so as to form an arc, there was observed a sudden con- traction of that leg of the recently killed frog; and this he interpreted as only evidence of an excitation of the peculiar electricity that was in the nerve and leg of the frog. He evi- dently did not comprehend that he had before him two dis- coveries in the one first experiment; that he was in fact de- monstrating most clearly what we now know as galvanism, while