STRYCHNIA-STIMULATION OF AUKICLE. 



615 



in normal rhythm the induced ventricular contraction. This is 

 observed when the electrodes are placed near the base of the 



P2. 



stimulation of Ventricle. 

 1. Before injection of strychnia. 2. After injection of strychnia. 



Fra. 2^9. 



Time-marker, recording seconds. All tracings in Appendix C taken at this 

 speed, except S and T. 



ventricle, or when stimulation is passed through the same 

 portion of the heart from the float to an electrode placed 

 beneath the heart upon the supporting shelf. After the maxi- 

 mum of systole, however, the auricular contraction succeeds the 

 induced ventricular. Both these facts are demonstrated in 

 Fig. 210 Q, in which this occasional increased auricular 

 excitability is shown. 



Auricular Stimulation. 



Occasionally maximal stimulation applied to the auricle pro- 

 duces at all times an auricular contraction succeeded by a 

 ventricular ; more usually, however, this relationsliip exists 

 only up to the maximum of systole (ventricular), and thereafter 

 the induced auricular beat succseds the ventricular. 



