46 RESPONSE IN THE LIVING AND NON-LIVING 



is therefore difficult to fix an absolutely neutral point, 

 but a point may be found which approaches this very 

 nearly, and on stimulating the stalk near this, a very 

 interesting diphasic variation has been observed. In 

 a specimen of cauliflower-stalk, (1) stimulus was applied 

 very much nearer A than B (the feeble disturbance 

 reaching B was negligible). The resulting response 

 was upward and the recovery took place in about sixty 

 seconds. 



FIG. 26. DIAPHASIC VARIATION 



(2) Stimulus was next applied near B. The resulting 

 response was now downward (fig. 26, b). 



(3) The stimulus was now applied near the approxi- 

 mately neutral point N. In this case, owing to a slight 

 difference in the rates of propagation in the two direc- 

 tions, a very interesting diphasic variation was pro- 

 duced (fig. 26, c). From the record it will be seen 

 that the disturbance arrived earlier at A than at B. 

 This produced an upward response. But during the 



