On the Interpretation of the Electrocardiogram. 293 
to a break induction shock. The stimulating electrodes are then moved 
in successive steps towards the right margin along the line joining the two 
Fig. 12a. 
leads, and the successive curves are obtained. In this way the right and 
left variations are in curve 1 separated by a time interval corresponding 
Fio. Vlh. 
to the conduction time of the excitation for a stretch of tissue of 40 mm., 
and the right variation is in advance of the left. In curve 4 the two varia- 
