80 CHAP. X. THE ELECTRIC RESPONSE TO LIGHT 



action of C0 2 is clearly seen in the autonomous pulsations 

 of the Desmodium leaflet (fig. 23). The normal response is 



Fig. 23. Arrest of Desmodium pulsation under excess of C0 2 

 at arrow, and renewal on removal of the Gas 



Fig. 24. Depression of Electric Response of Hy drill a under 

 excess of Carbon Dioxide 



(a) Normal response ; (b) depressed response under application 

 of excess of CO a at arrow. 



arrested by the action of this gas, and its removal is followed 

 by restoration of normal activity. 



