DUPLICATED LAYER 345 



this it might at first appear that the geo-perceptive layer 

 must always be single. There is, however, an interesting 

 variation which is described below. 



Experiment 186. — While experimenting with a specimen 

 which was supplied from a nursery garden as the Cape Mari- 

 gold (a species of Calendula), I was at first greatly puzzled 

 by the fact that this stem exhibited two definite electric 

 maxima during the passage of the probe from the surface 

 to the pith. Thus in a given specimen, while the geo- 

 electric response of galvanometric negativity at a depth 

 of o • 10 mm. was — 60 divisions, it increased abruptly to 

 — 115 divisions at 0-20 mm., and declined to — 15 at the 

 greater depth of 0-30 mm. The response continued to 

 decline till a depth of • 60 was reached, when the response 

 exhibited a second maximum, this time of — 105 divisions. 

 Below this the excitatory reaction showed decline and 

 abolition. Detailed results are given in the following table : 



Table XXVI. — Showing Duplication of Geo-Perceptive Layer. 



Similar duplication of the geo-electric maximum was also 

 observed in a second specimen of the same plant. On 

 examining sections of the stem, it was a matter of great 

 surprise to find that there were two definite starch-layers 

 separated from each other by a distance of about 0-4 mm. ; 

 it was at these starch-sheaths that the maximum excita- 

 tions were observed. 



