THE GENESIS OF FUNCTIONAL INERTIA 117 



Bose sums up,* " In both we have under normal 

 conditions .' a positive variation ' (of the injury 

 or resting current, or current of reference), in 

 both the intensity of response, up to a certain 

 limit, increases with the duration of illumination, 

 in both there is comparatively little fatigue, the 

 increase of response with intensity of stimulus is 

 similar in both, and finally even in abnormalities 

 such as reversal of response, preliminary negative 

 twitch on cessation of illumination, and decline and 

 reversal under continued action of light parallel 

 effects are noticed." Professor Bose does not in 

 this resume include a phenomenon he had recorded 

 in his experiments on the photo-electric cell, viz., 

 electric after-oscillations strictly comparable with 

 after-action (after-image) on the retina when light 

 was shut off. Clearly this latter is due to the inertia 

 of movement of molecules in the "cell" and in the 

 retina respectively katabolic inertia as truly as the 

 opposite phenomenon, the imposition of limits, is 

 due to inertia expressed functionally as an in- 

 susceptibility. 



Particularly curious is the parallelism between 

 " dosing " a tin wire with small and with large 

 amounts of K*OH and the well-known difference 

 between the effects of large and small doses of certain 

 drugs, e.g., alcohol : small doses increase the electrical 

 responses, while larger depress or abolish them.f 



From the evidence we have examined in the fore- 

 going pages we have strong grounds for believing 



* ]Loc. cit. p. 167. t Ibid. p. 146. 



