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 ease 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—z.e. the point at which the 
feeble contraction begins. Now, what I wish to be 
gathered from the whule tracing is this. If the 
strength 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 siightly 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 
