500 ON THE PHYSIOLOGICAL ACTION OF CASCA BAEK. 



Pulse 48 



Pulse 60. Clonic convulsions. 



Ventricle stopped in systole, firmly contracted in its 

 greater part, with a pouch-like dilatation of a small 

 portion. Auricles still contracting. 

 12 27. Ventricle firmly contracted. Still partial contraction 

 of auricles. Kespiration and slight convulsive move- 

 ments continue. 

 12 50. Eemoved from frog-board. The ventricle is not so 

 firmly contracted. Still respiring and occasionally 

 conviilsed. 

 1 P.M. Ventricle relaxed. Slight movements of it have 

 recommenced. 1*4 c.c. alcohol solution again in- 

 jected. 

 1 7. Ventricle again firmly contracted. No respiration. 



Still slight reflex movement. 

 1 30. Died with heart in same condition. 



Experiment XXX.— May 10. 



The heart of a frog was exposed, and a little extract of casca 

 placed on it. Pulse 34 per minute. 



It had no apparent action. 



A watery solution of casca was then poured into the thorax. 

 The pulse became slower, = 24 per minute. 



The ventricle then expanded irregularly ; the diastole at the 

 base being later than that at the apex. 



Then the distention became imperfect, the ventricle seeming 

 wrinkled. 



The heart then stopped in systole, having two pin-point, 

 dilated pouches on it. 



These experiments show that a very weak solution of casca 

 applied to a frog's heart, when removed from the body, slows 

 its pulsations, while, after the application of a stronger solution,, 

 the pulsations become slow, then the systolic contraction ceases 

 to take place instantaneously over the whole surface of the 

 ventricle ; lastly, the heart stands still in systole. 



AVhen the heart of a frog is exposed, but not removed from 



