STROPHANTHUS SARMENTOSUS : ITS PHARMACOLOGICAL ACTION. 



383 



Experiment L V. — continued. 



Interval. 



Contractions in 10 seconds. 



Notes. 



Auricles. 



Ventricle. 



After Strophanthus. 

 2 hours 5 mins. . 



2 „ 15 „ 



2 ,, 35 ,, 



2 „ 45 „ . 



3 „ . . 



3 „ 15 mins. . 



3 „ 40 „ . 

 y ,, 45 ,, 



10 „ 50 „ . 



11 „ 20 „ . 



12 „ 31 „ . 



12 „ 40 „ . 



2 



4 



4 



4 

 4 



3 



2 



4 



4 



4 

 4 



3 



Systole is performed fairly rapidly ; the diastolic phase is 

 prolonged. 



Each alternate ventricular contraction is superficial, the 

 intervening contractions are complete. 



Do. do. 

 Do. do. 

 Do. do. 



Do. In diastole, the auricles are well dilated; in systole, 

 they expel their contents almost completely. 



One of these ventricular contractions was a localised dimpling 

 only ; the others were powerful contractions ; the auricles 

 are contracting and expanding well. 



Six contractions of the auricles and ventricle occur in 30 

 seconds ; they are almost regular in time ; the left auricle 

 contracts first, then the right ; their contraction is rapid 

 hut incomplete ; the ventricle contracts after the right 

 auricle; it usually becomes uniformly pale in systole and 

 very small ; sometimes a wave of contraction passes over 

 the ventricle from left to right ; the systolic movements of 

 the heart are rapid ; the diastolic phase is prolonged. 



Six auricular and two ventricular contractions occur in 30 

 seconds ; two or four auricular contractions precede each 

 ventricular contraction ; after contraction, the ventricle 

 relaxes a little, and the successive auricular contractions 

 distend it more and more ; finally, it again contracts, and 

 so on. 



Heart arrested with all chambers greatly dilated. 



Six auricular and six ventricular contractions in 30 seconds ; 

 notes as at 9 hours 45 minutes. 



Arrest of the heart with all chambers fully dilated. 



From these experiments it appears that, with the smallest doses of extract used, the 

 first change is the greater completeness of the systolic movement of the ventricle, and 

 this occurs very early. Soon afterwards, the ventricle becomes more expanded in 

 diastole, while the rate of the heart's contractions becomes slower. At this stage, the 

 contractions are regular in time, and the ventricular systole occupies two-thirds of the 

 ventricular cycle, as in the normal heart. This condition is followed by changes in the 

 cardiac cycle ; at first the time of the ventricular cycle becomes equally divided between 

 systole and diastole, and afterwards ventricular diastole is the longer phase, the contrac- 

 tions of the heart continuing to occur at regular intervals up to this point. When the 

 diastolic phase begins to predominate, the ventricle relaxes very rapidly after contract- 

 ing and it is already well dilated when the auricles contract. Irregular pauses in 

 diastole soon interrupt the regularity of the cardiac contractions ; these pauses occur 

 spontaneously, but they can be induced at times by stimulation of peripheral nerves. 



