GEO-ELECTRTC RESPONSE OP SHOOT 45.^ 



deflection practically disappeared in the further course of 

 a minute and a half (Fig. 16<S). There was a small 

 " excitation remainder ''. But with vigorous specimens the 

 recovery is complete. 



The latent period of quickly reacting petiole of Tro- 

 pceolum is thus about 5 seconds, a value which is more 

 consonant with the idea of particles inducing excitation by 

 their fall through an exceedingly short distance. In very 

 sluggish organs latent period may be as long as a 

 minute (Fig. I(i9), which is considerably shorter than an 



Fi(i. lf)9. — Geo-electric response of the scape of Vricl'i!:. 



hour, the generally accepted value. Further even in the 

 electric response, the latent period will be delayed beyond 

 the period of perception. For this perception takes place 

 in some unknown sensitive layer in the interior of the 

 tissue, while electric contact is made with the epidermis 

 outside. It is obvious that certain time must elapse before 

 the excitation, initiated at the sensitive layer, should reach 

 the epidermis. Under ideal conditions of experiment which 



