Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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readily induced by the very sudden change, than by the more gradual application and removal of the electrode. Therefore we obtain a rule in practice, that where we wish to tone up, or produce increased excitability, the quick, metallic making and breaking of the current is best. Also, for this, the choice of a brisk current through hard, moist, and moderate-sized electrodes is best. While, for toning down, the gentle putting on of the electrodes, and taking them away again after a more length// application, and this while the even current is still running, is always to be preferred; so, for this end, we should also choose the large, fine, and softest sponge electrodes, and employ the most gently managed, even, and moderate current. We shall sometimes find that we can obtain, even from a medium labile ivorking, a moderate degree of down-toning in abnormally exalted nerves. But we must not be too confident that the stabile in-working of the constant current through a nerve produces, by the induced electro-tonus, a diminishing of capability or of sensibility under all conditions and to any ex- tent. Rather will we meet, in practice, with the more uniform facts that invite us to the view that the reestablishment or the increase of the somewhat existing electro-tonus in the nerve fibrils and muscle fibres, by means of stabile currents, is the very best means for bringing the nerves into a condition most suitable for the normal or natural conduction of both peripheral and central impressions. It is now ascertained, as I am inclined to believe, that the cur- rent variations, even when small, are sufficient to produce changes in the density and uniform direction of the native nerve current, and are more powerful and effectual to arouse an in- creased susceptibility in the nerve, for the future working of the applied current, than the stabile in-working acting even for a longer time. Our experience also teaches that the increase of susceptibility in a nerve, appearing at a labile in-working, is seen not only at the entrance and leaving of the same current, but even with a weaker current; so that, for instance, where a nerve is not susceptible to the action of a given primary current, — say from ten elements, — yet it will be made to acquire this aptitude