Abstract
(1) Threshold strength-duration for transverse field stimulation of muscle in normal ringer is given by a relation with two time constants which are independent of temperature.
(2) Increase of latency relaxation with transverse field strength of stimulation in normal ringer (Goodall, 1958) is not due to synchronisation of stimulus.
(3) In choline ringer the amplitude of both latency relaxation and twitch height varies for low levels of stimulation as the sixth power of the field for pulses of constant duration.
(4) This amplitude depends linearly on duration after an apparent induction time.
(5) The induction time is temperature dependent and smaller than would be expected from the charging time of the membrane derived from (1).
(6) The amplitude for constant stimulation depends on resting potential, having a maximum somewhat below the normal resting potential.
(7) On replacing chloride by nitrate the amplitude is increased and this maximum shifted to a higher potential.
(8) Induction time increases with potassium concentration and is independent of calcium.
(9) Two pulse experiments show that activity following an undirectional pulse is localised to one side of the fibres.
