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 lar2:e 

 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 eiFect 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 

 13 



