386 



SIR THOMAS R. FRASER AND MR ALISTER T. MACKENZIE ON 



Experiment L VI. — continued. 



Interval. 



Contractions in 10 seconds. 



Notes. 



Auricles. 



Ventricle. 



After Strophanthus. 

 75 minutes . 



77 „ . . 



82 „ . 



95 „ . 



... 





Eleven contractions of the heart in 30 seconds, followed by 

 a pause of 35 seconds during which the auricles were 

 dilated and the ventricle contracted. 



A similar pause for 30 seconds. 



In 30 seconds twelve cardiac contractions occurred in which 

 ventricular systole preceded auricular systole, and then a 

 short pause followed in each cycle ; thereafter a pause of 

 40 seconds' duration followed, in which the auricles were 

 dilated and the ventricle contracted ; then the auricles gave 

 a single spontaneous contraction, followed by contraction of 

 the ventricle, and after that ventricular systole preceded 

 auricular systole for ten contractions. Such series of 

 contractions were seen several times. 



Final arrest of the heart with the ventricle small and pale 

 and the auricles large and dark. 



Experiment LVII. — 0'0004 gram of extract instilled within the pericardial sac of a 

 frog (Rana temporaria), and later 0'000025 gram of sulphate of atropine. 





Contractions in 10 seconds. 





Interval. 





Notes. 









Auricles. 



Ventricle. 





Be/ore Strophanthus. 









1 minute 



6 



6 



Contractions powerful and regular in time ; ventricular systole 



occupies two-thirds of the cycle. 

 Inserted 0004 gram of extract of Strophanthus in Ringer's 



solution inside the pericardial sac. 



After Strophanthus. 









5 minutes . 



6 



6 



As last noted; perhaps the relaxation of the ventricle in 

 diastole is less complete. 



10 „ . . 



6 



6 



Ventricular systole is a little more complete ; the auricles fill 

 and empty well. 



15 . . 



5 



5 



Contractions regular and powerful; ventricular diastole occupies 

 one-half of the cycle and begins before auricular systole ; in 

 systole the ventricle becomes very small and very pale. 



16 „ . . 







Slight pauses in diastole are occurring. 



17 . 







Five auricular and five ventricular contractions occur in 30 

 seconds ; the slowness is due to diastolic pauses after each 

 relaxation of the heart. 



19 „ . . 







Three auricular and three ventricular contraction sin 30 seconds; 

 in systole the ventricle becomes very small and pale. 



20 „ . 



... 



... 



Inserted 0000025 gram of atropine sulphate in solution 

 inside the pericardial sac. 



22 . . 



... 





Four auricular and four ventricular contractions in 30 seconds ; 

 characters as last noted. 



25 



... 





As at 19 minutes. 



