390 SIR THOMAS R. FRASER AND MR ALTSTER T. MACKENZIE ON 



These experiments show that the administration of atropine before extract of 

 S. sarmentosus does not prevent the occurrence of those changes in the heart of the 

 frog which are characteristic of the action of Strophanthus when the vagus is active. 



Heart Perfusion through the Hepatic Vein. 



This method of obtaining a graphic record of the movements of the frog's heart has 

 been in use for some time. In the following experiments a constant head of fluid was 

 not used, as the most satisfactory results were obtained by adjusting at the beginning 

 of the experiment the inflow of fluid into the heart so as to give the best movements 

 for each heart employed. When this was obtained, it was kept constant throughout 

 the experiment. Rana esculenta was used and frogs weighing 30 to 40 grams were 

 selected. The brain was destroyed. 



Experiment LX. — Heart perfusion {Rana esculenta), first with Ringer's solution 

 and then with S. sarmentosus extract in Ringer's solution (1 in a million). (Plate IV.) 



12.48 p.m. During the perfusion of Ringer's solution only, the rate of the heart's contractions is 34 



per minute and the size of the movement is 12 mm. (Fig. 1.) 

 1 p.m. At this time, when the extract is first perfused, the rate of contraction is 30 per minute 



and the extent of the movement is 1 1 mm. (Fig. 2.) 

 1.5. Five minutes after the perfusion of extract began, the rate of contraction is 27 per minute 



and the size of the movement is 11 mm. (Fig. 3.) 

 1.17. The rate of contraction is 24 per minute and the size is 12 mm. The diminished rate is 



seen to be due to lengthening of the diastolic pause. (Fig. 4.) 

 2.30. The rate of contraction is 24 per minute and the size is 12 mm. The auricular contraction 



is seen to occur very quickly after diastole, and a small notch on the up-stroke indicates 



how the auricles begin to relax before the ventricle contracts. (Fig. 5.) 

 2.50. Rate 24 per minute ; extent 10 mm. 

 2.52. Rate 25 per minute; extent 10 mm. 

 3.5. Rate 25 per minute; extent 10 mm. (Fig. 6.) Short pauses in diastole are well seen. 



After each the first auricular contraction is larger. The ventricular contraction is 



smaller than before. 

 3.15. Rate 28 per minute; extent 9 mm. (Fig. 7.) The diastolic pauses have disappeared ; the 



diminished extent of movement is in the ventricular part of the tracing. 

 3.42. Rate 24 per minute ; extent 8 mm. (Fig. 8.) The notch due to relaxation of the auricles 



before the ventricle contracts is well seen ; the diminished extent of the movement is 



seen to be due to the ventricular movement. 

 3.54. Kate 25 per minute; extent 7 mm. As last described. 

 4 p.m. Rate 23 per minute; extent 7 mm. 

 4.15. Rate 23 per minute; extent 7 mm. 

 4.30. Rate 22 per minute; extent 5 mm. (Fig. 9.) The auricular movement is larger than at 



first and now exceeds the ventricular. In diastole all chambers are very large, and in 



systole the ventricular contraction is imperfect. 

 5.13. The highest contractions are ventricular; all the others are auricular. (Fig. 10.) Con- 

 tractions occur in series. Each series begins and ends with an auricular contraction ; 



otherwise the auricles and ventricle contract alternately. The auricles relax again 



before the ventricle contracts. All chambers are very large in diastole ; ventricular 



systole is very feeble; auricular systole is good. 

 5.30. As at 5.13. 



