4.")(3 DR THOMAS R. ERASER ON STROPHANTHUS HISPIDUS. 



Experiment Plate X. 



I. Kill. Tracings of detached gastrocnemius muscle of frog. Muscle only stimulated. 1, muscle in saline; 

 2 to 10, muscle in saline solution of extract of Strophanthus (1:2000). Fibrillary twitches are 

 represented in tracings 2 to 5. Reads left to right. 



Plate XI. 



LXIV. Tracings of detached gastrocnemius muscle of frog. Muscle only stimulated. 1, muscle in normal 

 saline; 2 to 10, muscle in saline solution of extract of Strophanthus (1:2000). Reads right to 

 left. 



Plate XII. 



LXV. Tracings of detached gastrocnemius muscle of frog. Muscle only stimulated. 1, muscle in normal 

 saline; 2 to 5, muscle in saline solution of extract of Strophanthus (1:25,000). Reads left to 

 right. 

 LXVI. Tracings of detached gastrocnemius muscle of frog. Although curves were obtained by stimulation 

 of both nerve and muscle, only those obtained by stimulation of the muscle have been reproduced. 

 1, muscle in normal saline ; 2 and 3, muscle in saline solution of strophanthin (1:20,000). 

 Reads right to left.* 



Plate XIII. 



LXX1X. Frog-heart tracings. 1, before, and 2 to 11, after application of strophanthin to the heart. 3, shows 

 increase of ventricular dilatation and contraction, and slowing of the rate due to prolongation of 

 ventricular diastole ; 10 and 11, show increased systole with lessened ventricular dilatation, and 

 in both the latter the larger portion of each curve (a in 11) represents the effect on the ventricle 

 of contraction of the auricles, and the smaller succeeding portion the greatly reduced ventricular 

 movement during contraction of the now continuously small ventricle. 



Plate XIV. 



LXXX. Frog-heart tracings. 1, before, and 2 to 11, after application of strophanthin to the heart. Great 

 increase of the ventricular dilatation caused by the auricular contractions is shown in tracings 4 

 to 9, and, especially, in 5, 6, and 7. 



Plate XV. 



LXXXI. Frog-heart tracings. 1, before application of strophanthin, shows a feebly acting heart, due to the 

 frog having been pithed on the previous day; 2 to 17 show the changes produced by the appli- 

 cation of strophanthin. In 3 and 4, the ventricular movements are much increased : in 5 and 6, 

 they have become irregular ; in 9 and 10, the systolic condition has been much increased in the 

 ventricle, allowing of only slight dilatation of its cavity; and in 11 to 17, the ventricular move- 

 ments have again become large, both diastolic expansion and systolic contraction being much 

 greater than at any previous time, and the heart's rate has become slowed by great prolongation 

 of ventricular diastole. 



Plate XVI. 



CXIII. Frog-heart tracings. 1, before atropine; 2, after application of atropine to the heart; and 3 to 11, 

 after application of atropine and strophanthin. Tracings 3 to 10 show much increase of the 

 effect of the auricular contractions on the ventricle. During the latter part of the experiment, 

 slowing of the rate was chiefly caused by stand-still of the ventricle in diastole, but, ultimately 

 (tracing 11), ventricular diastole was lessened. 



* In Experiments LXI., LXIII., and LXV. the speed of rotation of the drum was greater than in Experiments 

 LXIL, LXIV., and LXVI. 



