] dealing with experiments nearly exclusively on man, describe more or less completely the quantitative and time relations between the two without attempting an analysis of the phenomenon.Such an attempt, however, seems to be justified not only by the importance ascribed to the chronaxie as an index to neuromuscular reactivity, but also by the extensive changes which appear to result from hyperventilation. We have investigated the conditions essential to the occurrence of the effect of forced breathing on the motor chronaxie and are reporting our results in the present paper.
METHODThe experiments have been conducted on rabbits in urethane narcosis (1 g./kg. body weight). The motor chronaxie was measured either at the median nerve trunk or at the motor-point of the group of flexors innervated by this nerve (for localization see Banu [1922] and Reiners [1936]).The chronaximeter used in our experiments was a variable conaenser instrument of the ordinary type (source of current: City supply, 220 V. D.C.; variable condenser, 0 001-1 ,uF.; fixed condenser, 5 HF.). On its way to the animal the stimulating current passed through a resistance of 8300 Q. and one of 6400 Q., both the latter one and the animal being