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

of the discussion, or from his peculiar disposition, notwithstand- ing his masterly learning and unquestioned ability, he could not see, or would not admit, the co-existing truth of his contempo- rary's theory of animal electricity. He utterly denied the exist- ence of any sort of animal electricity, while he demonstrated that the arc of two different metals was the origin and cause of the electricity, and of the new wonder. And here were the germs of two stupendous discoveries ; at first so apparently small as to be insignificant, and so imperfect and contradictory as to appear worthless, yet two fundamental laws in nature, — animal electricity and galvanism — with which mankind will ever after have much and still more and more to do. A very sharp and protracted discussion arose between Galvani and Volta, and their respective partisans in all countries, in re- spect to the first and sole cause of the contractions produced by given means in the legs of the frog. Galvani persisted in assuming the existence of an animal electricity, which he be- lieved to be positive on the surface of each muscle, while the negative electricity was condensed in the interior or body of the muscle, much as it can be in a Leyden jar, and that the nerves serve merely as conductors between the two coatings of this living species of Leyden jar. What a paradox! Yet, years afterwards, when Sir Charles Bell had discovered and pointed out the difference between the motory and sensory nerves, as being true in anatomy, this long doubted and even scouted idea of Galvani was seen and acknowledged to be not so far from the truth. But in those days, as we have said, Volta made it appear most conclusively that the electricity developed and man- ifested so curiously, was merely from the contact of two hetero- geneous metals ; and what confirmed this opinion was the simul- taneous discovery of the power of the pile by Professor Volta; the construction of which was his own invention, but after all it was only the suggestion of Galvani's experiment, which was so dog- gedly opposed by M. Volta. Professor Galvani demonstrated, the next year after, that this contraction could be produced in the frog also by means of an arc or conductor of but one kind and piece of metal, or even without employing any kind of metal at all. 7