36 RESPONSE IN THE LIVING AND NON-LIVING 
is thrown into a state of complete tetanus, in which it 
appears to be held rigid. If the rapidity be not suffi- 
cient for this, we have the jagged curve of incomplete 
tetanus. If there is not much fatigue, the upper part 
N\A 

Fic. 16.—Unirorm Responses (RapisH) 
of the tetanic curve is approximately horizontal, but 
in cases where fatigue sets in quickly, the fact is shown 
by the rapid decline of the curve. With regard to all 
these points we find strict parallels in plant response. 
In cases where there is 
@ (6) no fatigue, the successive 
responses are identical (fig. 
16). With superposition 
of stimuli we have fusion 
Fissdly? Shree wees of effects, analogous to the 
Rapipiy SuccEEpine Srmvxr tetanus of muscle (fig. 17). 
And lastly, the influence 
of fatigue in plants is to produce a modification of 
response-curve exactly similar to that of muscle (see 
(a) in muscle; (6) in carrot. 
below). One effect of superposition of stimuli may be 
mentioned here. 
