MULTIPLE AND AUTONOMOUS ELECTRICAL RESPONSE 211 



energy already accumulated and held latent in the tissue, 

 aided by the incidence of external stimulus ; or from the 

 excessive accumulation of such latent energy alone. There 

 is thus a continuity between multiple and autonomically 

 responding plants. Biophytum, which under ordinary cir- 

 cumstances belongs to the former of these classes, becomes 

 converted into the latter under exceptionally favourable 

 tonic conditions. That is to say, it responds by a single 

 response to a single moderate stimulus, and by multiple 



FIG. 140. Induction of Autonomous Response in Biophytum 

 at Moderately High Temperature of 35 C. 



Note the diminution of amplitude of response with falling temperature. 

 The pulsations came to a stop below 29 C. 



responses to a strong stimulus. Under exceptionally favour- 

 able tonic conditions, however, it exhibits spontaneous or 

 autonomous responses. Desmodiumgyrans> on the other hand, 

 which ordinarily exhibits autonomous response, will, under 

 unfavourable circumstances, cease to exhibit spontaneous 

 movements. It then exhibits a single response to a single 

 moderate stimulus, and multiple responses to a single strong 

 stimulus : 



When the leaflet of this plant, owing to deficit of internal 

 energy, is in a state of standstill, a renewal of the supply of 

 stimulus will restore it to a condition of autonomous response. 

 This is seen in the following record (fig. 141) of the response 



p.J 



