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

the electricity which requires a given rule and regulation for its employment, as also those physiological and remedial results that are brought about by any prescribed method of use, are de- termined, in part at least, by the kind and efficiency of apparatus used to provide the given electricity. This proposition maybe transposed thus: A correct rule for using one kind of electricity does not always necessarily apply for the use of another elec- tricity, whether it relates to the kind as static or dynamic — to intensity or quantity — to Galvanic or to Faradaic electricity — to constant, inconstant, or alternated currents ; nor will there follow the same safety or danger, failure or success. With our eye on the kind and power of current employed by Dr. Duchenne, we will proceed to pass in review his leading propositions and modus operandi. When dry excitors are applied to the skin that is also dry, he says, there is produced a sensation of heat or burning only; but if the skin is likewise thick, then there is no kind of sensation. If, then, the electrodes are wet, or the skin is wet, neither spark, nor crepitation, nor sensation of heat is produced ; but a phenom- enon according to the position of the electrodes. If they are planted over the body of a muscle, then there is a contraction of that muscle, or at least of the superficial portion of it, together with a sensation that is not peculiar to the skin, but that always more or less accompanies the electro-muscular contraction. He defines this sensation as being like that produced by acting on a muscle that, for example, has been laid bare by a wound, so as to be no longer covered by the skin. Again, if the electrodes are positioned over the course of a mixed nerve, then contractions of all the muscles animated by this nerve are produced. Hence the proposition for his two grand different methods of proceeding: first, by applying the electrodes directly to the body of the muscle ; second, by apply- ing them rather to the nerve trunk that animates those muscles. The first method he designates as " direct muscular Faradaiza- tion," the second method as " indirect muscular Faradaization." In both cases he directs that the electrodes and the skin should be wet. For this purpose he employs mostly large wet