29 
together, it being believed that if there were a decrease in toxicity 
the half of this sum or any proportion representing half this sum 
would surely not cause death. The sum of the minimum fatal doses 
being 0.0020, the initial doses were estimated as about one-half of 
this amount, or 0.0010. But when given in proportions the sum of 
which equaled 0.0010 the mixture also proved fatal, showing not 
only no antagonism but a summation effect even. Further experi- 
ments were then carried out in which smaller amounts than half the 
sums of the minimum lethal doses were injected. Likewise these 
doses, even when slightly less than half the amount of the minimum 
lethal dose, always proved fatal, thus indicating more emphaticalty 
not only a summation effect in the toxic action of the two drugs but 
even some sjmergistic action. The time after the injections were 
made until death of the animal was also shorter, and this served as 
further proof of an increased toxicity. Some of the results obtained 
in these experiments are given in Table XI. 
Table XI . — Determination of the minimum lethal dose for mice of mixtures of acetanilide 
and caffeine citrate, hypodermic injection. 
[— =survived; + = death; A= acetanilide, and C=cafCeine citrate.] 
Dose per 
Hours 
Weight. 
gram body 
Result. 
till 
weight. 
death. 
17. 51 
f A 0. 0006 
\ - 
\ C . 0001 
/ 
14. 15 
/ A . 0006 
\ C . 0002 
i - 
- 
i 
16. 01 
f A . 0007 
\ C . 0001 
/ 
12. 77 
1 A . 0007 
1 C . 0002 
} - 
7. 30 
12. 96 
J A . 0007 
\ C . 0002 
} - 
9. 00 
14. 62 
1 A . 0008 
1 C . 0001 
} - 
4.50 ^ 
12. 55 
I A . 0008 
1 C . 0001 
} - 
2.30 1 
14. 34 
/ A . 0009 
\ C . 0001 
} - 
3.37 
20. 83 
1 A . 0009 
\ C . 0001 
) - 
3. 12 
16. 73 
/ A . 0007 
\ C . 0003 
} - 
9. 52 
15. 04 
J A . 0007 
\ C . 0004 
} - 
4. 40 
15.73 
/ A . 0009 
\ C . 0002 
} + 
4. 49 
14. 56 
/ A . 0009 
\ C . 0002 
} - 
2. 20 
FEEDING EXPERIMENTS. 
The hypodermic method of administering the antipyretics is 
rarely, if ever, used, at least in recent years, in the therapeutic appli- 
cation of these drugs. In order, therefore, to carry out experiments 
more closely simulating the ordinary methods of giving them, a 
series of feeding experiments was planned, using white mice and 
guinea pigs as experimental animals. In all cases the animals for 
