Electromotive plienoin. of the Mammal, heart. 281 



Plate XVI. 

 All curves lo be read from left to righi. 



Fig'. 14. Strip of tortoise ventricle cooled at hoth ends, showing negativity of 



stimulated end preceding that ot more distant end. Time-trace '/»"• 



(Stimulated end to capillary.) 

 Fig. 15. A similar preparation warmed at end distant from stimulation, cooled at 



stimulated end, showing a triphasic variation produced as described under 



figs. 4 and 5 in text. Time-trace '/g". 

 Fig. 16. A similar preparation, showing complete reversal of variation produced 



by cooling stimulated end and warming more distant end, showing 



negativity of more distant end preceding that of directly stimulated end. 



Time-trace Vs"- 

 Fig. 17. Left auricle and apex behind led off. Auricle excited under electrode. 



Latent period 0.12". Time-trace Vino"- 

 Fig. 18. Base and apex led off. Right auricular appendage excited. Latent 



period 0.12". Time-trace Vioo"- (I^ase to acid.) 

 Fig. 19. Base and apex led off, base to acid, apex to mercury in capillary. Left 



auricular appendage excited. Latent period 0.12". Time-trace Vioo"- 

 Fig. 20. Base and apex led off, excited ^4 iw- from base electrode. Latent period 



not more then 0.01". Time-trace Vioo"- 

 Fig. 21. Excised heart in warm chamber. Apex and base of right ventricle behind 



led off. Right auricle excited , it responded to excitation. Latent 



period 0.20". Time-trace Vioo"- (Base to acid.) 

 Fig. 22. „Stepped" curve. Excised heart in warm chamber, beating spontaneously. 



Time-trace V^oo"• (Base to acid.) 



Plate XVII. 



All curves to be read from right to left. 



Fig. 23. Electrical variation of human heart (E. H. S.) led off from apex heat and 



right hand. Middle curve is carotid beat. Time-tracing Vio"- Apex beat 



to capillary. Rt. hand to acid. 

 Fig. 24. Similar curve from another heart. (W. M. B.) Apex to acid. Hand to 



capillary. 

 Fig. 25. Similar curve from dog under morphia. Led off from apex beat and 



right fore-paw. Connections as in Fig. 24. 



