14 
If 
immovably by a clamp. Einger’s solution, (sodiimi chloride 0.7, 
potassium chloride 0.03, and calcium chloride 0.026 per cent), was 
used as a perfusing fluid. The venous cannida was connected with 
the outlet of the Y tube, while the aortic cannula was supported in 
such a manner that the perfused fluid would flow back over the heart, 
thus keepmg it moist and in good condition. The heart with certain 
exceptions as noted below was started by perfusiog it with Einger’s 
solution at a temperature of 20 to 22" and the rate and output per 
five-minute periods were recorded. TThen a normal had been ascer- 
tained acetanilide in varying per cent in Einger’s perfusing fluid was 
substituted, and after the efl’ect of this solution had been determined 
this was replaced by acetanflide of the same strength, but to which 
had been added either cafleine citrate or sodium bicarbonate and the 
output and rate again recorded as before. 
In estimating the effect of acetanihde alone and in combination 
with other drugs, it was first planned to use a sufficient concentration 
to poison the heart to such an extent that it would stop beating after 
twenty or thirty minutes. The drug in large doses being of itself a 
depressant of the heart, it was thought that the rate and output worfld 
both grow gradually less and less, and that finally the heart would 
stop beating. Such a course of progressive poisoning, however, does 
not seem to follow. After perfusing with strong solutions (one-haK 
to one-fifth per cent) the heart is found to cease beating almost in- 
stantly; slightly weaker solutions (one-sixth to one-tenth per cent) 
would stop the heart in some cases either at once or after a few 
minutes, or again would not stop it although perfused through it for 
an hom- or more. Protocols illustrating this action of the drug are 
given in Table I. 
Table I . — Perfusion of the isolated frog's heart icith Fingers solution and acetanilide. 
Protocol 20.. October 12, 190S- 
Protocol 25, October 13, 19(». j 
Output 
Output 
Time. 
Rate. 
per 
Time. 
Rate. i>er 
5 minutes. 
5 minutes. 
C. c. 
C.c. 1 
9.50 
26 
2.00 
2S ' 
9. 55 
26 
21 
2.a5 
29 ie *i 
10.00 
25 
25 
Acetanilide, i per cent. ■ 
Acetanilide. \ per cent. 
2.10 ' 
12 5 j 
10.02 
13 
2.14 
0 
10. te 
13 
9 
10.10 
10 
7 
10. 15 
10 
7 
10.20 
9 
7 
10.30 
u 
s 
10.40 
12 
9 
10.50 
11.10 
12 
14 
10 
In Other respects the efl’ect on the rate is veiw regiflar. Almost 
immediately after the introduction of the dmg the rate decreases to 
