PART 5.— ANAPHYLACTIN. 
THE PRESENCE OF ANAPHYLACTIN DURING THE PERIOD OF 
INCUBATION. 
It is of some interest to determine just when the substance called 
anaphylactin by Gay and Southard appears in the blood of a sensi- 
tized guinea pig, particularly whether its presence may be demon- 
strated during the period of incubation. 
A series of guinea pigs was therefore sensitized by the subcutaneous 
injection of 1/100 c. c. of normal horse serum. On each succeeding 
day two guinea pigs of this series were bled and the serum obtained 
by whipping and centrifugation. This serum was then injected into 
normal pigs. In twenty-four hours these pigs were tested by the 
injection of 6 c. c. of horse serum intraperitoneally. In the latter 
part of the series forty-eight hours were allowed to elapse before the 
pigs were tested. 
It will be seen from Tables 31 and 32, which give our work on this 
factor in detail, that no indication of anaphylactin appeared in the 
blood of sensitized guinea pigs until the tenth day. 
Table No. 31 . — Anaphylactin during the period of incubation. 
G. P. 
No. 
First injection. 
Inter- 
val in 
days. 
Second injection. 
1 Result. 
1343 A 
2 c. c. subcutaneously serum G . P. 
1343, which was bled 1 day after 
subcutaneous injection of 0.01 
c. c. normal horse serum. 
1 
0.25 c. c. normal horse se- 
rum into hrain. 
j No symptoms. 
1343B 
do 
1 
5 e. c. normal horse serum 
intraperitoneally. 
No symptoms. 
1 
1344A 
4 c. c. serum G. P. 1344, which was 
bled 2 days after injection of 
0.01 c. c. normal horse serum. 
1 
6 c. c. normal horse serum 
intraperitoneally . 
No symptoms. 
i 
1345A 
3 c. e. serum G. P. 1345, which was 
bled 3 days after injection of 
0.01 c. c. normal horse serum. 
1 
do 
No symptoms. 
1345B 
.. ..do 
1 
do 
No symptoms. 
No symptoms. 
1346A 
2.5 c. c. serum G. P. 1346, which 
was hied Ji days after injection 
of 0.01 e. c. normal horse serum. 
1 
do 
1346B 
do 
1 
do 
No symptoms. 
( 31 ) 
