Abstract
INTRODUCTION It has ever and quite naturally been true that the discovery of a new structure immediately has started an effort on the part of investigators to determine the function thereof, and conversely that the discovery of a new function or property has initiated an effort to discover some structure that could be made the seat of such function or property. The history of the localization of impulse initiation and impulse conduction in the heart illustrates in a striking manner these tendencies and their effects. The heart is spontaneously rhythmical. Does it contain a definite structure whose purpose it is to initiate this spontaneous rhythm? Or, again, in the heart, impulses are carried from one part to another. Is this the function of a special structure? Conversely, a structure is found in the heart which conceivably might act as pace-maker, while still another is found which might well