ELECTROCARDIOGRAM 21 



cally the electrical axis, using the hypothesis of distributed potential 

 differences, and one arrives at a result which is not consistent with 

 observation. According to this hypothesis, relative negativity should 

 appear, first of all, at the basal contact ; secondly when the wave of 

 excitation reaches the apex, the apical contact should appear relatively 

 negative ; finally when the wave returns to the base, the basal contact 

 should again show relative negativity. The second and last suppositions 

 are not in accord with the facts. But if, on the other hand, one 

 arranges the potentials theoretically, using the hypothesis of limited 

 potential differences, harmony exists. 



In the light of these observations and in the light of those previously 

 described, I have no hesitation in discarding the older hypothesis and in 

 accepting in its place the hypothesis which I term that of limited 

 potential differences. It is in accord, so far as can be seen, with all 

 present observations on heart muscle. I do not claim that it affords 

 a final explanation, being quite prepared to find that future observations 

 will necessitate its modification; but it is desirable, nay it is essential, 

 that we should possess ourselves of an hypothesis which harmonizes 

 with all present day observation; an hypothesis which will serve to 

 direct further experiment along fruitful channels. Hypotheses which 

 are out of harmony with present observations will not serve this pur- 

 pose. The present hypothesis has been put forward and is now empha- 

 sized in the belief that it will supply our present and immediate needs. 



Reprinted from the Archives of Internal Medicine 

 September 15, 1922. Vol. 30, pp. 269-285 



COPYRIGHT, 1922 



AMERICAN MEDICAL ASSOCIATION 



FIVE HUNDRED AND THIRTY-FIVE NORTH DEARBORN STREET 

 CHICAGO 



