MULTIPLE AND AUTOMATIC RESPONSE 289 



other hand, often gives rise to a multiple series of electric 

 responses. 



In Biophytum, similarly, while a moderate stimulus gives 

 rise to a single mechanical response, a strong stimidus 

 gives rise to a multiple series of responses. 



These multiple responses are induced by various modes 

 of strong stimulation such as induction-shock, constant 

 current, strong light, thermal shock, and chemical excita- 

 tion. 



Certain plant tissues have the power of holding the 

 excess of stimulus latent, to be given out later in the form 

 of recurrent responses. 



The characteristics of the response of Biophytum are like 

 those of cardiac tissue of the animal. Both are characterised 

 by long refractory period and response on ' all-or-none ' 

 principle. A single moderate stimulus gives rise to a single 

 response in both, and a strong stimulus gives rise to a multiple 

 series of responses. 



There is no strict Hne of demarcation between the 

 phenomena of multiple and of automatic response. In very 

 favourable circumstances of absorption of excess of energy 

 from without, an ordinarily responding plant like Biophytum 

 will become converted into an apparently automatically 

 responding plant like Desmodium. 



Conversely, under unfavourable conditions, that is to 

 say, when the sum-total of its energy is below par, an 

 automatically responding plant like Desmodium will 

 become converted into an ordinarily responding plant like 

 Biophytum. Its leaflets then come to a state of standstill. 



