igo 



CHAP. XVII. WIRELESS STIMULATION 



the incidence of the wave and the response, was only a 

 matter of a few seconds in very sensitive specimens 

 (fig. Ill, h). The record given in the figure was taken 

 with the moderate magnification of 2000 times only. But 

 with my Magnetic Crescograph the magnification can easily 



Fig. III. Record of responses to electric wave with the 

 Balanced Crescograph. 

 a, Response to feeble stimulation by acceleration of growth 



(down-curve), 

 fe. Response to strong stimulation by retardation (up-curve). 

 ^ c', Response to medium stimulation — retardation followed by 

 '^ recovery. Note down-curve in this figure represents accelera- 



tion, and up-curve retardation of growth. (Wheat.) 



be raised to ten million times, and the response of the plant 

 to space-signalling can be increased in the same proportion. 



Under an intensity of stimulation shghtly above the 

 minimal, the responses exhibit retardation of growth followed 

 by recovery, as seen in the series of records (fig. iii, c). 



A remarkable peculiarity in the response was noticed 

 during the course of the experiment. Strong stimulation 

 by ether waves gives rise, as already stated, to marked 

 retardation of the rate of growth. Repeated stimulation 



