51 
The mice being of the same lot as in the determination of the 
minimum lethal dose for caffeine, this was not redetermined in these 
experiments. 
The experiments ^\dth acetanihde and caffeine having shown no 
antagonistic action, the experiments using a mixture of antipyrine 
and caffeine were begun with relatively small doses. Half the sums 
of the minimum lethal dose for each drug were used as a basis for 
estimating the probable amomit of the mixtiu'e necessary to cause 
death. Antipyrine and caffeine were given in varHng proportions, 
except that the relative amount of antipmlne was always the greater. 
The result of the whole series was to show that the two drugs were 
not antagonistic, death resulting invariably from half the sums of 
the doses of the two drugs, and when exliibited in smaller amoimts 
faihng to kill. This indicates mere summation, but no s^mergistic 
action, as in the case of acetanihde-caffeine mixtures. Protocols 
taken from this series of experiments are given in Table Y. 
Table V. — Determination of the mimimum lethal dose of a mixture of antipyrine and 
caffeine citrate for white mice, hypodermic injection. 
[— =siirvival; + = death; A=antipyrine; C=caffeine.] 
Dose per i Hours 
Weight. gram body ; Result. till 
\reight. ' death. 
2. 50 
2.35 
16.10 
1.35 
2.47 
1.30 
13.49... I 
15. 91... / 
15.14... 
I 
A 0. 0007 
C .0001 
A .0007 
C .0001 f 
A .0007 ) ^ 
i C .0002 I ' 
f A .0008 \ ^ 
13.28....; j. + 
A .0008 \ 
C .0001 ( ' 
A .0006 \ 
C .0003 / ~ 
A .0006 \ , 
\ C .0003 ( ^ 
A .0006 \ , 
C .0003 f ^ 
A .0006 \ , 
\ C .0003 I 
13.17... 
16. 53... 
14.82... 
15.92... 
13.20... 
FEEDING EXPERIMENTS. 
Guinea pigs were given a mixture composed of antipyrme and 
caffeine citrate to determme whether any modification in the toxicity 
of the former resulted. The method used was practically the same 
as that used in the experiments on acetanilide, the only modification 
being in the method of administration. Since both drugs are easily 
soluble in water^ they were given hi solution by means of a stomach 
tube (a small sized, semielastic urethral catheter). Xo control experi- 
ments were carried out with caffeine citrate, the control experiments 
of the acetanilide series serving this purpose, as the animals m both 
