EXPERIMENTS IN STIMULATION. 57 



answer the first of these questions, therefore, I built 

 up a staircase in the ordinary way, and then sud- 

 denly transferred the electrodes to the opposite side 

 of the umbrella from that on which they rested while 

 constructing the staircase. On now throwing in 

 another shock at this part of the contractile tissue 

 so remote from the part previously stimulated, the 

 response was a maximum response. Similarly, if 

 the electrodes were transferred in the way just 

 described, not after the maximum effect had been 

 attained, but at any point during the process of 

 constructing a staircase, the response given to the 

 next shock was of an intensity to make it rank as 

 the next step in the staircase. Hence, shifting the 

 position of the electrodes in no wise modifies the 

 peculiar eff'ect we are considering ; and this fact 

 conclusively proves that the effect is a general one, 

 pervading the whole mass of the contractile tissue, 

 and not confined to the locality whicli is the imme- 

 diate seat of stimulation. Nevertheless, this fact does 

 not tend to prove that the staircase effect depends 

 on the process of contraction as distinguished from 

 the process of stimulation, because the wave of the 

 former process must always precede that of the 

 latter. But, on the other hand, in this connection 

 it is of the first importance to remember the fact 

 already stated, viz. that a current which at the be- 

 ginning of a series of stimulations is of slightly less 

 than minimal intensity presently becomes minimal, 

 and eventually of much more than minimal in- 

 tensity — a staircase being thus built up of which 

 the first observable step (or contraction) only occurs 



