136 RESPONSE IN THE LIVING AND NON-LIVING 



record in fig. 85 shows how individually feeble stimuli 

 become markedly effective by superposition. 



Superposition of stimuli. The additive effect of suc- 

 ceeding stimuli will be seen from the above. The fusion 

 of effect will be incomplete if the frequency of stimula- 

 tion be not sufficiently great ; but it will tend to be more 



FIG. 86. INCOMPLETE AND COMPLETE FUSION OF EFFECT IN TIN 



As the frequency of stimulation is increased the fusion becomes more and more 

 complete. Vertical line to the right represents '1 volt. 



complete with higher frequency of stimulation (fig. 86). 

 We have here a parallel case to the complete and in- 

 complete tetanus of muscles, under similar conditions. 



By the addition of these rapidly succeeding stimuli, 

 a maximum effect is produced, and further stimulation 

 adds nothing to this. The effect is balanced by a force 



