. Electro-physiology. Electrophysiology. 274 ELECTRO-PHYSIOLOGY CHAP. the muscle, it is sufficient to cause a demonstrable anelectrotonic depression of excitability within the myopolar part of the nerve. With sensitive preparations, the height of the twitch discharged at ab by the ascending make induc- tion shock was then regularly less 1 when the region cd was simul- taneously polarised by a branch of the primary current. To Griin- hagen's conclusion that the anelec- trotonic depression of excitability at ab existed previous to the induction closure, coincided with the entry of the polar
. Electro-physiology. Electrophysiology. 274 ELECTRO-PHYSIOLOGY CHAP. the muscle, it is sufficient to cause a demonstrable anelectrotonic depression of excitability within the myopolar part of the nerve. With sensitive preparations, the height of the twitch discharged at ab by the ascending make induc- tion shock was then regularly less 1 when the region cd was simul- taneously polarised by a branch of the primary current. To Griin- hagen's conclusion that the anelec- trotonic depression of excitability at ab existed previous to the induction closure, coincided with the entry of the polarising current, Tschirjew (35) objected that with the combined action of the two currents, the induced exciting current must necessarily be weaker than in the other case, because a part of the inducing current would now be led into the nerve by the rheochord. But this objection is, as Hermann (35) subsequently pointed out, of no weight in view of the relations of resistance; since it can hardly be of consequence to the current in the primary coil of low resistance (1-2 Siemens' units), whether a branch current, sent into the nerve with its 40,000 to 70,000 units, is made or broken, as was also demonstrated experimentally by Baranowsky and Garre" (35, p. 449). Tschirjew's experiments on the rate of transmission of galvanic as well as excitatory charges in medullated nerve during electro- tonus led him to conclusions fundamentally different from those of his predecessors, and his views were subsequently confirmed by Bernstein in an investigation which we have not yet referred to. He stated that the electrotonic alterations in nerve are transmitted at a. rate approximating to that of excitation, Imt, generally speaking, somewhat lower. In order to determine the rate at which the anelectrotonic decrease of excitability in the nerve is transmitted, Tschirjew employed a method analogous to that of Wunclt. " The minimal stimulus which will discharge a twitch is deter- mined a
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