ARTIFICIAL RHYTHM. 183 



are in some way accidental, I may draw attention 

 to the fact that the period of latent stimulation is 

 the same in the case of all the curves. To render 

 this apparent, I have placed crosses below the 

 smaller curves, which show in each case the exact 

 point where the depressing effect of these smaller 

 curves on the ascending sweeps of the larger curves 

 first become apparent — i.e. the point at which the 

 feeble contraction begins. Now, what I wish to be 

 gathered from the whole tracing is this. If the 

 strenofth of the induction shocks had been much 

 greater than it was, all the contractions would have 

 become strong contractions, and tetanus would have 

 been the result. But, as the strength of the in- 

 duction shocks was only slightly more than minimal, 

 the exhaustion consequent on every strong con- 

 traction so far diminished the irritability of the 

 tissue that when, during the process of relaxation, 

 another shock of the same intensity was thrown in, 

 the stimulus was only strong enough, in relation to 

 the diminished irritability of the partly recovered 

 tissue, to cause a feeble contraction. And these 

 facts tend still further to substantiate the hypothesis 

 whereby I have sought to explain the phenomena 

 of artificial rhythm. 



Now, I think that the strictly rhythmic action 

 of the paralyzed swimming-bell of Aurelia in 

 answer to constant stimulation is a fact of the 

 highest significance ; for here we have a tissue 

 wholly, or almost wholly, deprived of its centres 

 of spontaneity, yet pulsating as rhythmically in 

 answer to artificial stimulation as it previously did 



