194 



Professor Jagadis Ch under Bose 



[Mav 29, 



movements of ])oth plants and animals are guided by laws which are 

 identical. |^;- \^ mnqsj 



Firstly, when, for convenience of experiment, we cnt oif the 

 leaflet, its spontaneous movements, like those of the heart, come to a 

 stop. But if we now subject the isolated leaflet, bj means of a fine 

 tube, to an added internal hydrostatic pressure, its pulsations are 

 renewed, and continue uninterrupted for a very long time (Fig. 16). 

 It is found again that the pulsation-frequency is increased under the 



Fig. 16. — Record of Automatic Pulsations in Desmrdium gyrans. 



action of warmth, and lessened under cold, increased frequency being 

 attended by diminution of amplitude, and vice versa. Under ether, 

 there is a temporary arrest, revival being possible when the va pom- 

 is blown off (Fig. 17). More fatal is the effect of chloroform. The 

 most extraordinary parallelism, however, lies in the fact that those 

 poisons which arrest the beat of the heart in a particular way, arrest 

 the plant-pulsation also in a corresponding manner, the arrest pro- 

 duced being either at systole or diastole, depending on the character- 



FiG. 17. — Arrest of Pulsation of Desmodium under 

 Ether; Restoration of Pulsation on Blowing 

 off Ether. The arrow indicates the time of applica- 

 tion. 



istic reaction of the poison. Taking advantage of the antagonistic 

 reactions of specific poisons, I have been able to revive a poisoned 

 leaflet by the application of another counteracting poison. 



Let us now enquire into the causes of these automatic movements 

 so-called. In experimenting with certain types of plant tissues, 

 I find that an external stimulus gives rise to the same amplitude of 

 response, whether the stimulus be feeble or strong. What happens, 

 then, to the excess of the incident energy ? It is not really lost. 



