FURTHER STUDIES UPON ANAPHYLAXIS. 
By Milton J. Bosenau, 
Surgeon, Director Hygienic Laboratory , U. S. Public Health, and Marine- Hospital Service, 
and 
John F. Anderson, 
Passed Assistant Surgeon, Assistant Director Hygienic Laboratory. U. S. Public Health 
and Marine- Hospital Service. 
PART 1.— THE PERIOD OF INCUBATION. 
In our first publication ^ from a limited series of experiments we 
found the ‘^period of incubation/’ or the time necessary to elapse 
between the first and second injection, to be about ten days. We 
here give the results of three series of tests in order to clear up 
the following interesting details concerning the period of incubation: 
(1) Does the hypersusceptibility come on abruptly or gradually? 
(2) Do guinea pigs sensitized in the brain have a shorter period of 
incubation than those sensitized subcutaneously? (3) Is the period 
of incubation constant or variable? 
Table No. 1. — Period of incubation. 
G. P. 
No. 
First injection. 
Inter- 
val in 
days. 
Second injection. 
Result. 
1436 
0.01 c. c. normal horse serum 
4 
6 c. c. normal horse serum sub- 
No symptoms. 
1437 
subcutaneously. 
do 
4 
cutaneously. 
do 
No symptoms. 
No symptoms. 
No symptoms. 
No symptoms. 
No symptoms. 
No symptoms. 
No symptoms. 
No symptoms. 
No symptoms. 
Slight symptoms. 
Slight symptoms. 
Marked symptoms. 
Marked symptoms. 
1438 
do 
5 
. . . do 
1439 
do 
5 
. . . do 
1440 
do 
6 
do 
1441 
do 
6 
do 
1442 
do 
7 
do 
1443 
do 
7 
do 
1444 
do 
8 
do 1 
1445 
do. 
8 
do 
1446 
do 
9 
do 
1447 
do 
9 
do 
1448 
do 
10 
do 
1449 
do 
10 
do 
a Manuscript submitted for publication May 5, 1908. 
^Rosenau, M. J., and Anderson, John F.: A study of the cause of sudden death following the in- 
jection of horse serum. Hyg. Lab. Bui. No. 29, April, 1906, 9.5 p. Also Bui. No. .36, Further studies 
upon hypersusceptibility and immunity. 
( 7 ) 
