340 



CHAP. XXX. THE GEO-PERCEPTIVE LAYER 



comparatively feeble, less than half the corresponding maxi- 

 mum negativity in the upper half. Microscopic section 

 showed that the geo-perceptive layers were identical with 

 the groups of statocysts forming the starch-crescents. 



Fig. 202. 



Fig. 203. 



Fig. 202. Distribution of geotropic excitability in the peduncle 

 of Nymphaea. Ordinate represents geo-electric excitation ; 

 abscissa, distance from upper surface of flower-stalk. The 

 diagrammatic section underneath shows the position of geo- 

 perceptive layer (starch-sheath) corresponding to maximum 

 induced galvanometric negativity and positivity in the two 

 halves. 



Fig. 203. Distribution of geotropic excitability in the shoot 



of Bryophyllum. 



Experiment 182. — I carried out similar experiments with 

 the shoot of Bryophyllum. The results are given in 

 Table XXIV ; the curve of the electric distribution along 

 the diameter is given in fig. 203. The characteristics of 

 this curve are the same as that of Nymphaea. The maxi- 

 mum galvanometric negativity occurred at the depth of 



