442 COMPARATIVE ELECTRO-PHYSIOLOGY 



above, and the other below, a differential action will be 

 induced as between the upper and lower sides, the upper 

 being relatively the more excited. In the following ex- 

 periment I took a specimen of Uriclis lily, and fixed the 

 entire plant horizontally, as seen in the figure (fig. 270). The 

 pivoted support allowed the responsive points A and B to 

 be at first lateral. Owing to symmetry there was now no 



FIG. 271. Geo-electric Response of the Physically Restrained Scape 

 of Uriclis Lily 



Up-curve represents responsive current from upper to lower surface during 

 action of geotropic stimulus. Down-curve represents recovery on 

 cessation of stimulus. Response commenced after latent period of one 

 minute ; after-effect persisted for two minutes. Breaks in curve are 

 due to obscuration of recording spot of light at brief intervals. 



differential action of gravity, nor consequent electrical varia- 

 tion, as between the two. The galvanometric record was 

 now a horizontal line. The specimen, on its support, was 

 next quickly rotated through 90. The statolithic particles 

 were thus displaced, falling on the inner tangential wall of 

 the upper side, and outer tangential wall of the lower. An 

 electrical response was perceived in about one minute, which 

 went on augmenting with time, the upper side being in- 

 creasingly galvanometrically negative (fig. 271). The fact 



