104 



PLANT RESPONSE 



to its original position is deceptive, and does not really indi- 

 cate a complete protoplasmic recovery. 



Uniform responses. — If the motile organ, however, be 

 restored, by an appropriate period of rest, to exactly its 

 original molecular condition, and therefore to its original 

 condition of excitability, it is clear that we ought to be 



Fig. 51. Uniform Electrical Responses (Radish) 



able to obtain uniform responses to uniform stimuli. That 

 this is true has been shown to be the case, with regard to the 

 responses of the leaflet of Biophytum, and the longitudinal 

 contractions of various radial organs (figs. 18 and 38). 

 By taking electromotive instead of mechanical responses, 

 I obtained a similar result, of uniform responses to uniform 

 stimuli, from various species of plants 

 (fig. 51). In the case of muscle, also, the 

 responses are found to be uniform, if 

 intervening periods of rest be allowed* 

 sufficient for full recovery (fig. 9). 



' Staircase' effect. — It is sometimes 

 found that a tissue falls into a sluggish 

 condition, and successive stimuli, by 

 increasing molecular mobility, have the 

 effect of gradually enhancing the re- 

 sponses, which are seen to increase in a ' staircase ' manner. 

 I give here an instance of this effect (fig. 52) in the case of 

 longitudinal response, obtained with a style of EucJiaris Lily. 



Fig. 52. Staircase Ef- 

 fect in Longitudinal 

 Mechanical Response 

 of Plant (Style of 

 Eucharis) 



