47 
Table VI. — Determination of toxic dose for Rana pipiens, Focke method — drug injected 
into leg lymph sacs — Continued. 
SUMMARY. 
Mulford No. 1. . . 
N. B. and Co 
B. W. and Co. . . 
H. B. and W.... 
S. and D 
Lloyd Bros 
P., D. and Co . . . 
Merrell 
Digitalone 1, 2, 3 
Preparation. 
V (value). 
3.8 
2.9 
2.7 
2.1 
2.1 
PERFUSION OF FROG’S HEART. 
The perfusion experiments upon excised frogs’ hearts were carried 
out by tying a cannula in the left trunk of the aorta and a second in 
the posterior vena cava near the heart. The isolated heart was per- 
fused under constant pressure with Ringer’s solution to which digi- 
talis in tincture strength was added so as to make a 1 per cent solu- 
tion. The time was noted until systolic stoppage of the heart 
appeared and the figures recorded indicate the number of minutes 
the heart continued beating after the introduction of the drug. The 
results obtained by this method are recorded in Table VII. 
