63 
which 378 days elapsed between the first treatment and the second 
injection. 
Xo. 
G. P. 
First injection. 
Interval. Second injection. ; 
Result. 
4515 
0.19 c. c. toxine 7—1 
Bays. 
238 6 c. c. normal horse ' 
Dead, 30 minutes. 
4527 
unit antitoxic horse 
serum (B. 27), sub- 
cutaneously. 
do - 
(roan) serum, in- 
traperitoneally. 
378 6 c. c. normal horse : 
Dead, 37 minutes. 
4495 
do 
; (Xo. 15) serum in- 
1 traperitoneally. 
365 do 
Xo symptoms. 
4495a 
Ditto, 2 days later. . 
Two young, born of above female (4495), tested as 
follows: 
tVben 7 days old, 1 c. c. normal horse (Xo. 15) 
Severe symptoms. 
Dead, 13 minutes. 
4495b 
serum, intraperitoneally. 
When 9 days old, 1 c. c. normal horse (Xo. 15) 
Dead, 12 minutes. 
serum, intraperitoneally. 
The above guinea pig (Xo. Ti95) showed no symptoms at all after 
receiving 6 c. c. of horse serum into the peritoneal cavity 365 days 
after the first injection. It was then given the same cpiantity of serum 
two days following and showed severe symptoms. We have had 
several such instances following intraperitoneal injections, and can 
only explain it by the fact that sometimes the serum enters the lumen 
of the intestine instead of the peritoneal cavity. We called attention 
to this probability in H 3 ^gienic Laboratory Bulletin Xo. 29, page 63. 
THE EFFECT OF FIRST INJECTIONS OF HORSE SERUM INTO GUINEA PIGS. 
Theobald Smith stated that guinea pigs which have received no 
preliminaiy doses of serum may die of a first injection; of 58 guinea 
pigs receiving 3 to 5 c. c. of diphtheria antitoxin with no preliminary 
treatment, 9 died and 49 showed no efi'ect, making 15.5 per cent of 
the guinea pigs reacting to the first injection of horse serum. In 
reph^ to a question. Smith stated that he did not know whether or not 
the animals were the young of guinea pigs that had been treated. 
AVe have injected many guinea pigs with horse serum and have 
never noted symptoms of death to follow the first injection, and can 
not help but believe that the results obtained by Smith are explained 
by our studies upon the maternal transmission of hvpersusceptibilit 3 v 
« Smith, Theobald: Discussion of Rosenaii and Anderson’s paper on “Hypersus- 
ceptibility.” Journ. Am. Med. Assn., Vol. 27, Xo. 13, Sept. 29, 1906, p. 1010. 
