60 RESPONSE IN THE LIVING AND NON-LIVING 



mine whether the undoubted changes induced by tem- 

 perature in the vital activity of plants would affect 

 electrical response. 



Effect of very low temperature. As regards the 

 influence of very low temperature, 1 had opportunities 

 of studying ths question on the sudden appearance 

 of frost. In the previous week, when the tempera- 

 ture was about 10 C., I had obtained strong electric 

 response in radishes whose value varied from *05 to 

 1 volt. But two or three days later, as the effect of the 

 frost, I found electric response to have practically 

 disappeared. A few radishes were, however, found 

 somewhat resistant, but the electric response had, even 

 in these cases, fallen from the average value of "075 Y. 

 under normal temperature to *003 V. after the frost. 

 That is to say, the average sensitiveness had been 

 reduced to about -^V 11 . On warming the frost-bitten 

 radish to 20 C. there was an appreciable revival, as 

 shown by increase in response. In specimens where 

 the effect of frost had been very great, i.e. in those 

 which showed little or no electric response, warming 

 did not restore responsiveness. From this it would 

 appear that frost killed some, which could not be 

 subsequently revived, whereas others were only re- 

 duced to a condition of torpidity, from which there 

 was revival on warming. 



I now tried the effect of artificial lowering of tem- 

 perature on various plants. A plant which is very 

 easily affected by cold is a certain species of Eucharis 

 lily. I first obtained responses with the leaf-stalk 

 of this lily at the ordinary temperature of the room 



