( 279 ) 
ON THE INTEEPEETATION OF THE ELECTROCAEDIOGEAM. 
By W. a. Jolly. 
(From the Physiology Laboratory of the South African College, 
Cape Town.) 
(Eead August 19, 1914.) 
As was first shown by Waller/" the human electrocardiogram can be 
recorded by connecting the two hands or the hand and foot with the 
terminals of a capillary electrometer. Since the introduction of 
Einthoven's string galvanometer the electrocardiogram has become of 
great importance in the diagnosis of pathological conditions in the heart. 
Fig. la. Fig. lb. 
The interpretation of the complex curve obtained has, however, remained 
obscure, and for its elucidation it is advisable to have recourse to 
experiments upon the simpler and more slowly acting hearts of cold- 
blooded animals, where it is possible to isolate a single chamber of the 
heart and to record the curves yielded by it when contracting either 
spontaneously or in response to artificial stimulation at one or other point 
of the musculature. 
Fig. la gives the typical form of the ventricular electrocardiogram from 
* Journ. of Physiol., vol. 8, p. 229, 1887. 
