ELECTROCARDIOGRAM 9 



during the past six years, and have obtained almost always the reply 

 that the direction of current flow will be the same as in the last example. 

 It is said that 1 will become negative relative to 3, and that conse- 

 quently Z will show negativity relative to C. Now, this reply is an 

 assumption ultimately based on the belief that the two methods of lead- 

 ing off are sufficiently similar; actually the experiment has not been 

 performed in this simple form. For a long while I have felt unable to 

 accept this view of what will happen. The view is inconsistent with 

 certain experiments which will be described presently. The view which 

 I put forward is that relative negativity will first develop at contact C; 

 and it will develop at C because, when 1 becomes active, we are leading 

 off from the embedded strip of muscle 1 to 2, and the remainder of the 

 strip 2 to 3 does not for the moment concern us. It does concern us 

 of course when the excitation wave in traveling along the strip moves 

 into the region between 2 and 3 ; when the wave in traveling has turned 

 the corner, Z will become relative to C, the flow of current becoming 

 in consequence reversed. But for the moment we shall do well to 

 concentrate attention on the first phase of the reaction, for this is in 

 dispute. 



The statement just made in respect of the first phase, brings us 

 I think to the critical arguments of the discussion, namely, does the 

 prolongation of the strip from 2 to 3 effect the reaction shown by the 

 galvanometer when 1 becomes active. The usual view has been that it 

 will. My own view is that it does not. 



You may ask, why the actual experiment is not performed? The 

 reply is that it cannot be carried out in so simple a fashion on cardiac 

 muscle which is uninjured, and that if you use injured muscle, your 

 experiment is open, on theoretic grounds, to serious criticism. But, as 

 I hope later to show, the experiment can be performed under somewhat 

 more complex conditions, and that it yields the results which I anticipate. 



The argument turns as stated on the influence or noninfluence of the 

 portion of muscle 2 to 3, on the initial electrical reaction. According to 

 one view, that which seems so far to have obtained the greater number 

 of direct or indirect supporters, you are to consider 1 as relatively 

 negative, and to consider the whole of the remainder of the muscle 

 as relatively positive. This view implies that in determining the direc- 

 tion of flow, you are to join the center of the active mass of muscle to 

 the center of the inactive mass. According to the other view, you are 

 to consider the part of the muscle which is becoming active as relatively 

 negative, and the inactive muscle in union with it and in its immediate 

 vicinity as relatively positive. I put forward this second view because 

 it is consistent with and explains my experiments and because so .far as 

 I am aware it is inconsistent with no other experimental facts ; the 

 first view, though it is admittedly consistent with many experiments, is 



