STROPHANTHUS SARMENTOSUS : ITS PHARMACOLOGICAL ACTION. 393 



Experiment LXIV. — Perfusion of the isolated ventricle of the frog's heart (Rana 

 temporaries) with Einger's solution, followed by extract of S. sarmentosus in Ringer's 

 solution (1 in 20,000). (Plate VIII.) 



4.20 p.m. Before Strophanthus, the rate of contraction was 10 per minute, the size of the movement 

 was 14 mm., there was no systolic pause, and the diastolic pause was well marked. 

 (Fig- 1.) 



4.22. Strophanthus perfused. (Fig. 1.) 



4.24. Rate 12 per minute; size of movement 15 mm. (Fig. 1.) The diastolic pause is shorter 

 and the systolic movement of the ventricle is increased. 



4.27. Rate 19 per minute; size of movement 17 mm. (Fig. 2.) The diastolic pause has almost 



disappeared and a systolic pause is beginning to appear. 



4.28. Rate 24 per minute; size of movement 17 mm. (Fig. 2.) There is no diastolic pause; 



evidence of imperfect relaxation of the ventricle is seen. 



4.32. Rate 20 per minute ; size of movement 14 mm. (Fig. 2.) The movements are becoming 

 irregular in time and are quite irregular in size. The level of ventricular systole is 

 almost a straight line and there is a distinct systolic pause ; the level of the diastolic 

 movement is very irregular, owing to the relaxation of the ventricle being imperfect. 

 Occasionally a complete relaxation occurs. 



4.38. Rate 13 per minute; size of movement 14 mm. (Fig. 3.) The systolic pause is very 

 distinct, the diastolic pause is beginning to reappear, and the movements are regular in 

 time and extent. This part of the tracing is like the normal inverted. 



4.42. Rate 11 per minute ; size of movement 11 mm. (Fig. 3.) The systolic pause is diminishing 

 and the diastolic is increasing. The notch at the beginning of the up-stroke is due to 

 the inrush of fluid during relaxation slightly over-distending the ventricle. The elasticity 

 of the muscle overcomes this and the rebound is marked on the tracing. 



4.47. The diastolic pause has become very distinct and the systolic has disappeared. The ventricle 

 became arrested in semi-diastole for 5 minutes, and then resumed its contractions 

 spontaneously. (Fig. 4.) 



4.53. Spontaneous movements of the ventricle after a long pause. (Fig. 5.) 



4.57. Peristaltic movements of the ventricle are now visible after contraction, and the tracing 

 (Fig. 5) gives a record of the largest. 

 5 p.m. The ventricle has ceased contracting and is in semi-diastole. It did not contract 

 spontaneously after this. 

 5.5. Peristaltic movements are still visible at the apex. 



In this experiment, in which the isolated ventricle was poisoned by Strophanthus, 

 there occurred a very distinct increase in the systolic movement of the ventricle and 

 an increase in the rate of contraction, accompanied by a decrease in the length of the 

 diastolic pauses. As the diastolic pauses disappeared, systolic pauses developed, and 

 the relaxation of the ventricle became incomplete. The heart again became slowed — 

 this time as a result of regular pauses in systole. Finally the systolic pauses became 

 shorter and shorter ; diastolic pauses reappeared and were longer than ever ; the 

 ventricle at one time remained in semi-diastole for 5 minutes and then contracted 

 regularly and spontaneously ; then peristaltic movements of the ventricle occurred 

 after each contraction, and ran from base to apex, and when the ventricle was per- 

 manently arrested in semi-diastole, these peristaltic movements continued at the apex. 



These perfusion experiments give results which agree with those obtained by the 

 direct application of the extract to the heart's surface, and they also indicate more 



