46 
The amoimt of fluid perfused is so irregular that no conclusions can 
he dra^m from changes in this factor. Experiments illustrative of 
these changes are given in table I. 
Table I . — Perfusion of the isolated frog's heart with antipyrine and with antipyrine and 
caffeine citrate in Ringers solution. 
Protocol 14. 
Protocol 17. 
Time. 
Rate. 
Output 
per 
o minutes. 
Time. 
Rate. 
Output 
per 
5 minutes. 
C. c. 
C. c. 
10.45 
39 
30 
9. 25 20 
35 
10.50 
38 
32 
9.30 18 
34 
-Autipyrme 0.8 per cent 
9. 35 19 
34 
4- caffeine cent. 
Antipyrine 0.8 per cent 
10.52 
19 
-i- caffeine j 
Der cent. 
10. 55 
15 
17 
9.40 17 
25 
11.00 
16 
13 
9. 45 18 
24 
11.10 
20 
5 
9.50 13 
10 
11.30 
18 
6 
Antipyrine 0.8 per cent. 
11.40 
19 
9 
9.55 17 
5 
Antipyrine O.S per cent. 
10. 00 17 
4 
11.42 
21 
10. 10 18 
5 
11.45 
21 
10 
10. 53 Still beating. 
11.50 
20 
9 
11. 55 
19 
10 
As had been the result in the case of acetanihde it was hoped that 
more dilute solutions of the drugs might give more definite results. 
Accordingly in a series of experiments the perfusions were begun 
with antipyrine in 0.5 per cent solution^ and after sufficient readings 
had been recorded to establish a normal a cafleine-antipyrine solution 
was turned on. It was shown by these experiments that caffeine 
quite consistently lessened the toxic effect of antipyrine to a slight 
‘extent, although occasional exceptions occurred. The protocols in 
Table II fllustrate the results obtained. 
Table II. — Perfusion of the isolated frog's heart with antipyrine and antipyrine-caffeine 
dissolved in Ringer’s solution. 
Protocol 26. 
Protocol 29. 
Time. 
Rate. 
Output 
per 
5 minutes. 
Time. 
Rate. 
Output 
per 
5 minutes. 
C. c. 
Antipyrine 0.5 per cent. 
' 9. 55 25 53 
10. 00 22 51 
10. 05 22 46 
1 10.10 ; 22 45 
10.15 i 20 42 
Antipyrine 0.5 per cent 
1 -i- caffeine per cent. 
! 10.17 : 22 
i 10.20 : 23 45 
10.25 ' 22 44 
, 10.30 : 22 44 
! 10.35 20 44 
; 10. 40 19 41 
C. c. 
AntipTTine 0.5 per cent. 
3. 30 ■ 24 49 
3. 35 23 46 
3. 40 19 46 
3. 45 19 46 
Antipyrine 0.5 per cent 
-i- caffeine per cent. 
3. 47 23 
3. 50 24 56 
3. 55 19 52 
