LOCALISATION OF THE LAYER 



339 



Table XXIII. — Showing the Distribution of Geotropic 



Excitability through the Peduncle of Nymphaea 



(diameter = 6-8 MM.). 



Localisation of Geo-Perceptive Layer 



A curve constructed from the data given above is seen 

 in fig. 202. The diameter of the peduncle was 6-8 mm. 

 The negative geo-electric response is seen to increase till 

 it attains a climax at the depth of i -4 mm. It then shows 

 a continuous diminution till it becomes zero at the depth of 

 3 mm., where there is a neutral zone which extends through 

 I mm. When the probe reaches a depth of 4-2 mm. 

 measured from the upper side, it enters a region affected by 

 the perceptive layer situated on the under side, the opposite 

 physiological reaction being indicated by induced electric 

 change of galvanometric positivity. This positivity reaches 

 a climax at a depth of 5-4 mm. measured from the upper, 

 and I '4 mm. measured from the lower, surface. The points 

 of maximum positivity and negativity are situated sym- 

 metrically in the two halves of the organ. The electric 

 variation of maximum positivity in the lower half is 



