LONGITUDINAL TRANSMISSION OP EFFECT OF STIMULUS 277 



iutensily was u negative curvature ; direct application of 

 light on the growing region gave, on the other hand, a 

 positive curvature an<l movement towards light. 



Thus while the effect of direct unilateral stimulation 

 is a positive curvature, tlie effect of indirect stimulation 

 is a negative curvature. The following table gives a 

 summary of results of tropic effects under unilateral 

 application of indirect stimulus. 



TAliLK XXlll. — SHOWING TROPIC EFFECT OF UNILATERAL 

 AITLU'ATION OF INDIRECT STIMULUS. 



IStiniulus. 



.Moik-rate 



Feeble 

 Moderate 



Cliaraoter of iuterveuiuj 

 tissue. 



Comliictiiig' 

 Seuii-coi:dacting 



Sena-coiiductiiig 

 Non-cou(Uictirig 



Sign of tropic 

 response. 



Positive curvature. 

 Negative followed 



by positive. 

 Negative curvature. 



Diiect application of unilateral stimulus induces a positive curva- 

 ture. 



SUMMARY. 



In sensitive plants stimulus applied at a distance 

 induces in the responding region an expansion indicative 

 of increase of turgor. 



The effect of indirect stimulation is also exhibited by 

 an electric change of galvanometric positivity, indicative of 

 enhancement of turgor and expansion. 



