laws, which are equally applicable to the conducting issue of the plant and the nerve of the animal : —
LAWS OF VARIATION OF NERVOUS CONDUCTION UNDER THE ACTION OF ELECTRIC CURRENTS.
1. The passage of a corrent induces a variation of conducti- vity, THE EFFECT DEPENDING ON THE DIRECTION AND INTENSITY of curbent.
2. Under feeble intensity, heterodromous current enhances, and homodromous current depresses, the conduction of excita- TION,
3. The after-effect of a feeble current is a transient conduc- tivity VARIATION, the SIGN OF WHICH IS OPPOSITE THAT INDUCED DURING THE CONTINUATION OF CURRENT.
SUMMARY.
The variatioQ of conductivity induced by the directive action of current has been investigated by two different methods : —
(1) The method in which the normal speed and its induced variation are automatically recorded ;
(2) That in which the variation in the intensity of transmitted excitations is gauged by the varying amplitudes of resulting responses.
The great difficulty arising from leakage of the excit- ing induction current into the polarising circuit was successfully overcome by the interposition of a choking coil.
The following summarises the effects of direction and intensity of an electric current, on transmission of excit- ation through the .conducting tissue of the plant.
The velocity of transmission is enhanced against the direction of a feeble current, and retarded in the direction of the current.
