322 RESEARCHES ON IRRITABILITY OF PLANTS 



effect of temperature and of drugs on the pulsating activity 

 of animal and vegetal tissues. 



Summary 



The rhythmic tissue of Desmodium, like the rhythmic 

 cardiac tissue, is incapable of tetanus. 



Pulsating leaflet of Desmodium, like the pulsating heart, 

 is more susceptible to excitation at diastole than at systole. 

 An extra pulsation is induced by an electric shock applied 

 during the diastolic phase. 



Transmitted excitation affects the normal pulsations of 

 rhythmic tissues — animal or vegetal — in a similar manner. 

 In certain circumstances the effect is one of inhibition ; 

 in other circumstances the effect is one of acceleration. 



