Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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studies relating to electro-therapeutics is of late enlarged by all these researches and discoveries ! " Is electrotonus the inseparable expression of the excitement produced by the steady current working during the closure of the circuit, and are the negative fluctuations of the native cur- rent of the nerves and muscles, on the contrary, the consequence and the expression of the fluctuation or interruption of the ex- citing current ? Then every research, even the most minute and delicate; that relates to the formation of these conditions, will be of influence on the vital question of relation or condition of the nerves in the human organism, according as they are exposed to steady currents, or to greater or less current fluctuations. Next in order comes " The Galvanic Current, a Preventer of Muscle Convulsions," a treatise by Dr. Eckhard ; the maxim of which is, " Every muscle convulsion responding too readily to the influence of some irritation, can be avoided by means of the constant galvanic current; and every tetanus already present can be removed by it." He proves this rule by three series of experiments, not on living- animals, but on amputated, and hence dead frog legs. These are the evidences: — 1. A nerve embraced in a circuit of four or five Daniell's ele- ments can be affected in the route of the current, without pro- ducing convulsions ; but these convulsions will at once reappear as soon as the current is opened. 2. If a nerve is saturated with a solution of kitchen salt, by which it is well known that a frog's leg is tetanized, and is then taken in the galvanic circuit, beyond or below the portion of the nerve irritated with the salt, then there does not arise any tetanus, or, if it does appear, it quickly vanishes as the circuit is closed. When the current is weak, an up-running current is most successful; but when stronger currents are employed, either direction is effectual. 3. If we now employ two batteries separately, but upon the same limb, so that the upper end of the nerve is embraced by the weaker battery circuit, at the same time that the lower extremity of the limb is in the stronger current, then the closure and opening of the upper circuit, during the constant closure of the