PLANT RESPONSE 75 
minute of the application of chloral, is also extremely 
well marked. 

Before A» After 
Fie. 45.—Acrion or CHnoran HyprRATE ON THE RESPONSES OF LEAF-STALK OF 
CAULIFLOWER 
Vibration of 25° at intervals of one minute. 
Response unaffected by variation of resistance.—In 
order to bring out clearly the main phenomena, I have 
postponed till now the consideration of a point of some 

Before 4} After 
Fre. 46.—Action or Formanrn (RaptsH) 
difficulty. To determine the influence of a reagent in 
modifying the excitability of the tissue, we rely upon 
its effect in exaltine or depressing the responsive E.M. 
