Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
192/740

There was another work, published by Dr. Richard Fowler, on " Experiments and Observations relative to the Influence lately discovered by M. Galvani, and commonly called Animal Electricity" in Edinboro', 1793. This English work con- tains very many curious and also interesting facts, showing how the case appeared at a distance in those earlier times of its history. Still another work may be mentioned, among the many that were put forth in England, which was by Dr. Wilkinson, in 1804, entitled " Elements of Galvanism," which contains much good hard sense in connection with this subject. Dr. Wilkinson found that two pieces, one of silver and the other of zinc, each pre- senting a superficial surface of only a hundredth part of an inch, produced violent contractions in the leg of a frog prepared after Galvani's method. At the same time he found that two circu- lar plates of zinc and copper require to be brought twenty times in contact with the condenser of the best electrometer then to be had, before any sensible divergence of the gold leaves of that instrument was produced. By comparing the area of these plates, multiplied by the number of contacts, with the superfi- cial surface of the minute pieces of silver and zinc employed to effect the muscular contraction of the leg of the frog, he arrived at the conclusion that the sensibility of the fresh-killed frog to electric currents is many thousand times greater, — or, in other words, more delicate as a test of electric currents, — than any of the most sensitive electrometers. It is worthy of notice, also, that the earliest and most distin- guished observers of these electro-muscular contractions men- tion the fact that the convulsions, as they were usually called, were more promptly and strongly produced after a certain num- ber of electric treatments, — and that by means of only a single pair, — than they were when first applied ; and that all the more marked if a moderate current was employed than when a very powerful current was used. Alexander von Humboldt made analogous observations from ad hominem experiments which he caused to be conducted upon his own shoulders. After having removed the cuticle on each shoulder by means of a cantharides