PLANT RESPONSE 57 
fatigue was present. It will be seen that the curves 
obtained by joining the apices of the successive single 
responses are very similar. 
In one case there is no fatigue, the recovery from 
each stimulus being complete. Every response in the 


Fig. 34.—ReEsponses TO INCREASING STIMULUS OBTAINED WITH Two SPECI- 
MENS OF STALK OF CAULIFLOWER 
In (a) fatigue is absent, in (b) it is present. 
series therefore starts from a position of perfect equi- 
librium, and the height of the single responses increases 
with increasing stimulation. But in the second case, 
