128 RESPONSE IN THE LIVING AND NON-LIVING 
this increase of response after tetanisation may be due to 
the hypothetical evolution of CO, to which allusion has 
previously been made. 
But there is an exact correspondence between this 
phenomenon and that exhibited by metals under 
similar conditions. I give here two sets of records 
(figs. 80, 81), one obtained with platinum and_ the 

Before dh After 
Fic. 81.—EnNuANcED Response IN TIN AFTER Continuous StimuLaT on T 
other with tin, which demonstrate how the response is 
enhanced after continuous stimulation im a manner 
exactly similar to that noticed in the case of nerve. 
The explanation which has been suggested with 
regard to the staircase effect—increased molecular 
mobility due to removal of sluggishness by repeated 
stimulation—would appear to be applicable in this case 
