18 
results in this series indicated that caffeme if sufiiciently dilute vcould 
antagonize, to some extent at least, the poisonous effects of acetanilide. 
There were some experiments which still showed greater toxicitv 
from the combination of drugs than from acetanilide alone, but these 
were oiffy occasional. However, they were sufficiently frequent to 
illustrate very well how incomplete the antagonism between these 
drugs really is. 
Protocols showing the results of this series of experiments are given 
in the folio whig table: 
Table IV. — Effect upon the isolated frog's heart of an acetanilide Pdngefs solution and a 
similar solution to which caffeiiw citrate had been added. 
Protocol 53. 
Protocol 50. 
Time. 
Rate. 
Output per 
5 minutes, 
Time. 
Rate. 
Output per 
5 minutes, 
Acetanilide per cent. 
Acetanilide W per cent. 
C. c. 
C. c. 
9.35 
22 
11 . 00 .... 
20 
9.40 
20 
54 
11.10 
15 
21 
9.45 
20 
52 
11.15 
17 
20 
9.50. . . . 
21 
50 
11.20 
17 
20 
9.55 
22 
53 
11.25 
16 
19 
10 . 00 ... 
22 
56 
Acetanilide per cent+caf- 
Acetanilide ^ per cent+caf- 
feine citrate per cent. 
feine citrate 
per cent. 
11.27 1 
1 16 
10 . 02 ... 
1 -■ 
11.30.... 
10 
IS 
10.05... 
! 26 
5S 
11.35 
14 
17 
10 . 10 ... 
27 
56 
11.40 
14 
15 
10.15... 
07 
57 
11.45 
14 
14 
10 . 20 ... 1 
1 25 
54 
Acetanilide per cent. 
Acetanilide tL per cent. 
11.47.... 
13 
10 . 22 ... 
23 
11.50 
12 
13 
10.25... 
23 
5S 
12.00 
12 
10 
10.35... 
22 
55 
To determine to what extent the presence of alkaline carbonates 
in the perfusion fluid would modify or prevent the toxic effects of 
acetanilide was then made the subject of a series of experiments. 
In this work no effort was made- to determine the length of time 
necessary to produce stoppage of the heart, but as in the later caf- 
feme-acet anilide experiments the comparison was made by noting 
the changes in rate and output. Acetanilide was used in only one- 
eighth per cent solution, but the amount of sodium bicarbonate and 
ammonium carbonate was varied from one three-hundredth to one- 
twentieth per cent. As far as could be determined there seemed to 
be no difference in the antagonistic value whether the base were sodium 
or ammonium. In all cases there proved to be a considerable degree 
of antagonism, but this was not at all sufficient to abolish or even 
prevent quite marked slowing and weakening from the toxic action 
of the acetanilide. The degree to which sodium bicarbonate is anti- 
dotal to acetanffide when perfused through the frog's heart is shown 
by the protocols given in Table Y. 
