228 
DR. A. D. WALLER AND MR. E. W. REID ON THE 
Tracing 14. 
Wave of contraction in Frog’s ventricle. Upper line apex, lower line base. Excitation near apex (a). 
Excitation near base (/3). 
Tracing 15. 
/J> 
Wave of contraction in spontaneous beat of Frog’s heart taken by double cardiograph. The move 
ment of the lever resting on the base precedes that of the lever resting on the apex. It is note 
worthy that in all cases the contraction at the base outlasts that at the apex. 
