35 
Table No. 33. — Anaphylactin 
in man 
monlcey, rabbit, and cat- 
—Continued. 
G. P. 
No. 
First Injection. 
Inter- 
val in 
days. 
Second injection. 
Result. 
Cat. 
285 
3 c. c. cat serum. 41 days prior 
1b 
C c. c. normal horse (roan) 
No symptoms. 
this cat had been injected with 
serum intraperitoneally. 
2 c. c. normal horse serum. 
Rabbit. 
1377 
8 c. c. rabbit serum. This rabbit 
2h 
No symptoms. 
had been frequently injected 
with normal horse serum . 
1378 
do 
2h 
0.2 c. c. normal horse (roan) 
No symptoms 
serum into brain. 
It will be noticed that a few of these guinea pigs showed symptoms^ 
but in every case an interval of at least two weeks elapsed between 
the first and the second injections. The slight reactions obtained 
were probably those which occur when serums of different species 
are used at the first and the second injections (heterologous serums, 
see Hyg. Lab. Bull. 29, p. 55, and Bull. 36, p. 25). 
ANAPHYLACTIN IN IMMUNE GUINEA PIGS. 
We submit some further work bearing upon the question whether 
guinea pigs ^ immunized’’ against the phenomenon of anaphylaxis 
are in a refractory state or have returned to the normal or are really 
immune. 
We first made a few experiments to determine whether guinea pigs 
immunized by repeated injections of small quantities of horse serum 
contain anaphylactin in their blood. In this series the guinea pigs 
received ten injections of 2 c. c. normal horse serum subcutaneously cov- 
ering a period of seventeen days. Eighteen days following the last 
injection the pigs were first tested for immunity and then bled. 
It developed from the following six guinea pigs that ten repeated 
subcutaneous injections (of 2 c. c. each) during the course of seven- 
teen days were not sufficient to completely immunize the guinea 
pigs, for those tested developed slight symptoms. Indications of 
anaphylactin were demonstrated in the blood serum of five of the 
six pigs of this series. However, it must be noted that when bled 
these animals were certainly immune from the last treatment, as we 
and others have shown that when a sensitive guinea pig responds to a 
second injection immunity is quickH established. (See G. P. No. 
671, Table 36.) 
