Electro-physiology (1896-98) Electro-physiology . electrophysiolog02bied Year: 1896-98 ix ELECTRICAL EXCITATION OF NERVE 125 wards broader, while the abruptly rising currents give the reverse, the decomposition being marked at first and subsequently diminishing (Fig. 177). While investigating this electrolyto- graphic method Griitzner also found that the steeply rising break induction current of an ordinary du Bois' sliding apparatus had a far more marked electrolytic action than the gradually rising- make induction current. In the frog's nerve-muscle preparation, with low intensity of curren
Electro-physiology (1896-98) Electro-physiology . electrophysiolog02bied Year: 1896-98 ix ELECTRICAL EXCITATION OF NERVE 125 wards broader, while the abruptly rising currents give the reverse, the decomposition being marked at first and subsequently diminishing (Fig. 177). While investigating this electrolyto- graphic method Griitzner also found that the steeply rising break induction current of an ordinary du Bois' sliding apparatus had a far more marked electrolytic action than the gradually rising- make induction current. In the frog's nerve-muscle preparation, with low intensity of current, abruptly rising currents are always the most effective (now one and now the other, according as the electrodes are situated on the nerve). On increasing the current, a second smaller twitch appears, corresponding with the other steeply rising FIG. 177. (and opposite) current. Further increase of current intensity complicates the excitatory effects still further, since with an ascending direction of current the anodic inhibition becomes apparent. In rare cases, all four induction currents may excite, and there are then at each revolution two strong and two weak twitches, alternating as one strong and one weak twitch. The most significant result of Griitzner's investigation is the pre- dominant action of the abruptly rising currents, where the direction is again of importance, inasmuch as (according to the observations of Hermann and Fleischl, supra] the upper portion of the nerve is first excited by descending, the lower portion by ascending currents, while they both take effect at the ' equator ' only. It is with much higher intensities of current that the gradually rising currents also become effective. The beneficial influence of great abruptness of oscillation is shown inter alia by the fact that even very strong currents may be shunted into the nerve without perceptible signs of excitation,
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