THE VALIDITY OF THE "ALL-OR-NONE" LAW IN THE PERIPHERAL NERVOUS SYSTEM OF CRUSTACEA

Abstract

Gradations in the contraction of the abductor of the dactylus of several decapods were produced by electrical or natural stimulation via the single excitatory axon. The duration of persistent discharges of nerve impulses was followed with a resistance-coupled amplifier and loud speaker and found to depend on the strength of the initiating induction shock. The all-or-none principle appears to hold in spite of the small number of axons. Gradation in the muscle is probably a summation effect produced by variations in frequency and duration of the impulse rhythm in the motor axon.