44 
horse serum due to the admixture with the serum of sensitive ani- 
mals. The symptoms in those animals which had received a mixture 
of sensitive guinea pig and horse serum appeared much quicker and 
were more violent than in those animals that received the horse 
serum alone or the horse serum plus the normal guinea pig serum. 
Moreover, death occurred in a smaller percentage of the control 
animals. 
We fully appreciate that it will require much more work upon this 
subject to definitely prove that the toxicity of horse serum is increased 
by admixture with sensitive guinea pig serum. The problem is a 
fundamental and important one, and is now engaging our attention. 
However, the limited data on hand seem sufficiently interesting 
and instructive to warrant publication at this time. 
We have been impressed in our work upon anaphylaxis that cau- 
tion must be observed in drawing conclusions from limited data 
because of our lack of knowledge of the fundamental principles 
involved, and the further fact that irregular results have occasion- 
ally been met with by almost all workers in this field. 
If our further results confirm this preliminary work, it would 
then appear that a reaction takes place either in the animal or, more 
likely, in the test tube, between the blood serum of sensitive guinea 
pigs and the horse serum, resulting in an increase in the toxicity of 
the horse serum. 
Table No. 20 . — Sensitized guinea pig serum plus normal horse serum. 
EXPERIMENT NO. 1. 
G. P. No. 
G. P. 
weight. 
First injection. 
Inter- 
val, in 
days. 
Second injection. 
Result. 
10969 
0.245 c. c. toxine 9+1/220 
c. c. antitoxic horse se- 
rum (Alex. A245) 
60 
0.1 c. c. equal mixture of 
sensitive guinea pig and 
normal horse (Frank) 
serum, into brain. 
Dead in 20 min- 
utes. 
10695 
0.245 c. c. toxine 9+1/240 
c. c. antitoxic horse se- 
rum (Alex. A245). 
60 
0.1 c. c. equal mixture of 
sensitive guinea pig and 
normal horse (Frank) 
serum, into brain. 
Dead in 3 minutes. 
10995 
0.245 c. c. toxine 9+1/500 
c. c. antitoxic horse se- 
rum (Alex. A249). 
60 
0.1 c. c. equal mixture of 
sensitive guinea pig and 
normal horse (Frank) 
serum, into brain. 
Dead in 4 minutes. 
10978....... 
0.245 c. c. toxine 9+1/270 
c. c. antitoxic horse se- 
rum (Alex. A245). 
60 
0.1 c. c. equal mixture of 
sensitive guinea pig and 
normal horse (Frank) 
serum, into brain. 
Dead in 4 minutes. 
11018 
0.245 c. c. toxine 9+1/640 
c. c. antitoxic horse se- 
rum (Alex. A245). 
60 
0.1 c. c. equal mixture of 
sensitive guinea pig and 
normal horse (Frank) 
serum, into brain. 
Dead in 4 minutes. 
