62 RESPONSE IN THE LIVING AND NON-LIVING 



temperature 0C., for twenty-four hours, and afterwards 

 took their records once more at the ordinary tempera- 

 ture of the room. From these it will be seen that 

 while the responsiveness of Eucharis lily, known to be 

 susceptible to the effect of cold, had entirely disappeared, 

 that of the hardier plants, Holly and Ivy, showed very 

 little change (fig. 36). 



Another very curious effect that I have noticed is 

 that when a plant approaches its death-point by reason 

 of excessively high or low temperature, not only is its 

 general responsiveness diminished almost to zero, but 

 even the slight response occasionally becomes reversed. 



Ivy Holly Eucharis 



FIG. 36. AFTER-EFFECT OF COLD ON IVY, HOLLY, .AND EUCHARIS LILY 



a. The normal response ; 6. Eesponse after subjection to freezing temperature for 

 twenty-four hours. 



Influence of high temperature, and determination of 

 death-point. I next tried to find out whether a rise of 

 temperature produced a depression of response, and 

 whether the response disappeared at a maximum tem- 

 perature the temperature of death-point. For this 

 purpose I took a batch of six radishes and obtained 

 from them responses at gradually increasing tempera- 

 tures. These specimens were obtained late in the 

 season, and their electric responsiveness was much 

 lower than those obtained earlier. The plant, previously 

 kept for five minutes in water at a definite temperature 



