Part XL 
HEREDITARY TRANSMISSION OF THE SUSCEPTIBILITY IN GUINEA 
PIGS. 
So far as may be judged from the following data on this subject the 
susceptibility to the toxi.c effects of horse serum may be transmitted 
from the mother guinea pig to her young: 
FAMILY NO. 1. 
Mother g. p. No. 105. One c. c. normal horse serum (roan) inoculated subcutaneously. 
Symptoms; recovered. 
[Previous treatment: 55 days prior, inoculated subcutaneously with c - c - normal 
horse serum (Jane).] 
The progeny of the above guinea pig, when about five days old, was 
tested as follows: 
G. P. No. 105A. One c. c. normal horse serum (roan) inoculated subcutaneously. Symp- 
toms; recovered. 
G. P. No. 105B. One c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Symptoms; recovered. 
FAMILY NO. 2. 
Mother g. p. No. 66. Six c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Dead in 120 minutes. 
[Previous treatment : 85 days prior, 6 c. c. normal horse serum (Sam) injected into the 
peritoneal cavity.] 
The progeny of the above guinea pig, when about a week old, was 
tested as follows: 
G. P. No. 66A. One c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Symptoms. 
G. P. No. 66B. Do. 
FAMILY NO. 3. 
Mother g. p. No. 103. Six c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Symptoms. 
[Previous treatment: 71 days prior, c. c. normal horse serum (Jane) inoculated 
subcutaneously; 33 days later 6 c. c. antitoxic horse serum (Natl. IX, 17) injected into the 
peritoneal cavity. Symptoms.] 
The progeny of the above guinea pig, when about ten days old, was 
tested as follows: 
G. P. No. 103A. One c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Symptoms. 
FAMILY NO. 4. 
Mother g. p. No. 4463. Six c. c. normal horse serum (roan) injected into the peritoneal 
cavity. Symptons (?). 
[Previous treatment: 99 days prior, inoculated subcutaneously with 0.22 c. c. toxine 
No. 7-j-2iro c - c - antitoxic horse serum (Natl. VIII, 17). 26 days later, 6 c. c. antitoxic 
horse serum (Natl. VIII, 17) -f liver pulp of normal guinea pig injected into the peritoneal 
cavity. Symptoms.] _ 
( 73 ) 
