CONTENTS xiii 



CHAPTEE XVI 



INORGANIC RESPONSE EFFECT OF CHEMICAL REAGENTS 



PAGE 



Action of chemical reagents Action of stimulants on metals Action 

 of depressants on metals Effect of ' poisons ' on metals Opposite 

 effect of large and small doses 139 



CHAPTEE XVII 



ON THE STIMULUS OF LIGHT AND RETINAL CURRENTS 



Visual impulse : (1) chemical theory ; (2) electrical theory Retinal 

 currents Normal response positive Inorganic response under 

 stimulus of light Typical experiment on the electrical effect in- 

 duced by light .......... 148 



CHAPTEE XVIII 



INORGANIC RESPONSE INFLUENCE OF VARIOUS CONDI- 

 TIONS ON THE RESPONSE TO STIMULUS OF LIGHT 



Effect of temperature Effect of increasing length of exposure Rela- 

 tion between intensity of light and magnitude of response After- 

 oscillation Abnormal effects: (1) preliminary negative twitch ; 

 (2) reversal of response ; (3) transient positive twitch on cessation 

 of light ; (4) decline and reversal Resume ..... 158 



CHAPTEE XIX 



VISUAL ANALOGUES 



Effect of light of short duration After-oscillation Positive and nega- 

 tive after-images Binocular alternation of vision Period of alter- 

 nation modified by physical condition After-images and their 

 revival Unconscious visual impression ..... 170 



CHAPTEE XX 

 GENERAL SURVEY AND CONCLUSION . . 181 



INDEX 193 



