54 
GROUP E, 
FAMILY NO. 16. 
(Untreated female; sensitized male.) 
Female (G. P. No. 606). September 7, 1906. Six c. c. horse serum intraperi- 
toneally. No prior treatment. No symptoms. 
Male (G. P. No. 606x). September 9, 1906. Six c. c. horse serum (roan) intraperi- 
toneally. Dead, 17 minutes. 
[Previous treatment: 106 days prior received 0.15 c. c. tox. 9-)-2io c. c. antitoxic 
horse serum (Natl. VIII, 18).] 
Offspring. Two young born August 4, 1906, and tested as follows: 
(G. P. No. 606a.) September 9, 1906. 1 month old. Two c. c. normal horse 
serum into peritoneum. No symptoms. 
(G. P. No. 606b.) September 9, 1906. 1 month old. Two c. c. normal horse 
serum (roan) into peritoneum. No symptoms. 
FAMILY NO. 17. 
(Untreated female; sensitized male.) 
Females (G. P. No. 609). January 25, 1907. Six c. c. normal horse serum (horse 
No. 15), intraperitoneally. No prior treatment. No symptoms. 
(G. P. No. 607). Ditto. No prior treatment. No symptoms. 
Male (G. P. No. 4527). January 25, 1907. Six c. c. normal horse serum (horse 
No. 15), intraperitoneally. Dead, 37 minutes. 
[Previous treatment: 1 year 13 days prior, 0.19 c. c. toxine No. 7-|-l unit B27.] 
June 8, 1906. Placed with untreated females Nos. 609 and 607. 
Offspring. December 26, 1906. Three young born to G. P. No. 609. September 6, 
1906. One young born to G. P. No. 607. 
Young tested as follows: 
(G. P. No. 609a). January 25, 1907. 30 days old. Two c. c. normal horse 
serum (horse No. 15) intraperitoneally. No symptoms. 
.(G. P. No. 609b). Ditto. No symptoms. 
(G. P. No. 609c). Ditto. No symptoms. 
(G. P. No. 607a). Ditto (141 days old). No symptoms. 
We conclude from these experiments that — 
1. Hypersusceptibility to the toxic action of horse serum is trans- 
mitted through the female guinea pig; the male has no influence. 
2. The susceptibilit}^ is not transmitted through the milk. 
3. Maternal transmission of h 3 ADersusceptibiiit}" succeeds, whether 
the female guinea pig is sensitized before or after conception. 
