SUMMARY 265 



equilibrium, the responsive after-effect being more rapid 

 than under light. The after-effect of prolonged exposure 



Fig. 154. Post- maximum after-effect of light on response of 



leaf of Cassia. 



There is an overshooting on cessation of light at arrow within 



a circle. 



is thus an ' overshooting ' beyond the normal position of 

 equilibrium. 



Summary 



The after-effect of light is modified by the duration of 

 the exposure. 



Under continued action of light, the electric response 

 of galvanometric negativity in plants attains a maximum, 

 after which it undergoes decline and neutralisation. 



The electric after-effect exhibits characteristic differ- 

 ences depending on the duration of the previous exposure 

 to light. 



The pre-maximum after-effect is a temporary continua- 

 tion of the response induced by light followed by recovery. 



The after-effect at maximum is an immediate recovery 

 to the normal equilibrium, 



