GROWTH OF THE TENDRIL 9I 



I have studied the effects of direct and indirect stimula- 

 tion on the growth of the tendril, employing not onl}^ 

 mechanical but also other kinds of stimuli as well, the 

 fundamental reaction being essentially similar in all cases. 

 I will first describe the effect of electric stimulation, since 

 the impact of this stimulus does not produce any mechanical 

 disturbance. 



Effects of Indirect and Direct Electric Stimulation 

 ON THE Growth of a Tendril 



For this investigation I took a growing tendril of 

 Cucurbita, the sensitiveness of which is more or less uniform 



Fig. 44. Fig. 45. 



Fig. 44. Diagrammatic representation of ^Method for the Indirect 



and Direct Electric Stimulation of tendril. 

 Fig. 45. Record by Method of Balance, showing acceleration 

 of growth of tendril (up-curve), induced by indirect electric 

 stimulation (Cucurbita). 



on all sides. The specimen was held in a clamp, and the 

 tip suitably attached to the recorder. For indirect stimula- 

 tion, a feeble current from an induction coil was applied 

 by two electric connections below the clamp. Direct 

 stimulation was effected by sending the current through 

 the length of the organ, the two electrodes being placed 

 the one above and the other below the clamp (fig. 44). 



Experiment 52. Effect of indirect electric stimulation. — 

 The tendril was mounted on a Balanced Crescograph, the 



