ARTIFICIAL RHYTHM. 181 
of at least two seconds’ duration. Thus, for in- 
stance, if the shocks were thrown in at the rate of 
one a second, the tissue only, but always, responded 
to every alternate shock. And similarly, as just 
stated, if any number of shocks were thrown in, 
the tissue only responded once in every two seconds. 
Now, as this rate of response precisely coincided 
with the rate of rhythm previously shown by the 
same tissue under the influence of faradaic stimula- 
tion of the same intensity, the experiment tended to 
verify the hypothesis which it was designed to test. 
I may give one other experiment having the 
same object and tendency. Employing single 
induction shocks of slightly more than minimal 
intensity, and throwing them in at twice the rate 
that was required to produce a strong response to 
every shock, I found that midway between every 
two strong responses there was a weak response. 
In other words, a stimulus of uniform intensity gives 
rise alternately to a strong and to a weak contrac- 
tion, as shown in the appended tracing (Fig. 27). 
It will be observed that in this tracing each large 
curve represents the whole time occupied by the 
strong contraction, the latter beginning at the 
highest point of the curve on the left-hand side in 
each case. The effect of the weak contraction is 
that of momentarily interrupting the even sweep 
of diastole after the strong contraction, and there- 
fore the result on the tracing is a slight depression 
in the otherwise even curve of ascent. Lest any 
doubt should arise from the smallness of the curves 
representing the weak contractions that the former 
- | 
