58 RESPONSE IN THE LIVING AND NON-LIVING 



the strain is not completely removed after any single 

 stimulation of the series. That recovery is partial is 

 seen by the gradual shifting of the base line upwards. 

 In the former case the base line is horizontal and re- 

 presents a condition of complete equilibrium. Now, 

 however, the base line, or line of modified equilibrium, is 

 tilted upwards. Thus even in this case if we measure 

 the heights of successive responses from the line of 

 absolute equilibrium, they will be found to increase with 

 increasing stimulus. Ordinarily, however, we make no 

 allowance for the shifting of the base line, measuring 

 response rather from the place of its previous recovery, 

 or from the point of modified equilibrium. Judged in 

 this way, the responses undergo an apparent diminution. 



