SUMMARY 347 



plant ; such specimens exhibit positive electric response 

 under the stimulus of prick, and feeble curvature under 

 geotropic stimulation. The large-sized starch-grains, nor- 

 mally observed in the starch-layer, are found to have 

 disappeared in specimens which prove to be geotropically 

 insensitive. 



The induced electric variation in a horizontal organ, 

 negative in the upper, positive in the lower, half, indicates 

 that the cortex contiguous to the upper perceptive layer 

 undergoes contraction, while that contiguous to the lower 

 perceptive layer undergoes expansion. 



