The transition will be seen to have commenced at the third and ended at the seventh, counting from the left.
Being desirous to trace this change gradually taking place, I took a platinum wire cell giving modified responses, and obtained a series of records of effects of individual stimuli continued for a long time. In this series, the points of transition from modified response to normal will be clearly seen ([fig. 78]).
Fig. 79.—The Normal Response a in Nerve Enhanced to b after Continuous Stimulation T (Waller)
The normal response in nerve is recorded ‘down.’
Fig. 80.—Enhanced Response in Platinum after Continuous Stimulation T
Increased response after continuous stimulation.—We have seen that responses to uniform stimuli sometimes show a staircase increase, apparently owing to the gradual removal of molecular sluggishness. Possibly analogous to this is the increase of response in nerve after continuous stimulation or tetanisation, observed by Waller ([fig. 79]). Like the staircase effect, this contravenes the commonly accepted theory of the dissimilation of tissue by stimulus, and the consequent depression of response. It is suggested by Waller that this increase of response after tetanisation may be due to the hypothetical evolution of CO2 to which allusion has previously been made.