62 
RESULT OF CARDIAC INJECTIONS. 
AYe have shown that guinea pigs may be readil}" sensitized by sub- 
cutaneous or intraperitoneal inoculations, and that the second injection 
produces sjmiptoms when the serum is injected either under the skin 
or into the peritoneal cavity. 
Besredka and Steinhardt have shown that the injection of serum 
into the brain of a sensitized guinea pig is very poisonous. We are 
able to confirm this observation. We then asked ourselves the ques- 
tion, Can guinea pigs be sensitized b}" injecting the horse serum 
directly into the heart ? And can sensitized guinea pigs be poisoned 
by such injections directly into the circulation? We are now enabled 
to answer these questions affirmativel}", in view of the following 
experiments: 
No. 
G. P. 
First injectioL. 
Interval. 
Second injection. 
Result. 
i 
Days. 
7077 
0.142 c. c. toxme o-i-of o 
131 
1.5 c, c. normal 
Dead, 3 minutes. 
c. c. antitoxic horse 
horse (roan) se- 
serum (XYBH. 17), 
subcutaneous!}'. 
rum, into heart. 
7692 . 
0.142 c. c. toxine 5+410 
35 
0.01 c. c. normal 
Dead, 55 minutes. 
c. c. antitoxic horse 
horse (roan) se- 
serum (A. 247), sub- 
cutaneously. 
rum, into heart. 
76?r. 
0.142c. c. toxine 5+3^0 
44 
1 c. c. normal horse 
Dead, 3| minutes. 
c. c. antitoxic horse 
(roan) serum. 
serum (A. ppt. 31), 
subcutaneously. 
into heart. 
CM 
CO 
CD 
0.142 c. c. toxine 5 
44 
do 
Dead, 3 minutes. 
c. c. antitoxic horse 
serum (A. ppt. 31), 
1 subcutaneously. 
7691 
0.142 c. c. toxine 
c. c. antitoxic horse 
35 
do 
Dead, 3 minutes. 
serum (A. 247), sub- 
cutaneously. 
Con- 
2 c. c. normal horse 
No symptoms. 
trol. 
(roan) serum, into 
heart. 
Same guinea pig 
20 days 
6 c. c. normal horse 
Marked symptoms. 
later. 
(roan) serum, in- 
traperitoneally. 
These experiments indicate that the endothelial cells lining the 
peritoneal cavity or the connective cells of the subcutaneous tissue do 
not necessarily play a role in the phenomenon we are studying. 
THE GUINEA PIG REMAINS SUSCEPTIBLE A VERY LONG TIME. 
That the guinea pig remains susceptible to the toxic action of horse 
serum a very long time is indicated in the following experiments, in 
