23 
G. P. No. 4931. Six c. c. normal horse serum (roan) inoculated subcutaneously. Dead in 
5 minutes. 
[Previous treatment : 34 days prior, inoculated subcutaneously with 0.139 c. c. toxine 
No. 5+3YQ c. c. antitoxic horse serum (Wellcome 475).] 
G. P. No. 4941. Six c. c. normal horse serum (roan) inoculated subcutaneously. Dead in 
20 minutes. 
[Previous treatment: 34 days prior, inoculated subcutaneously with 0.139 c. c. toxine 
No. 5+y-jyo c. c. antitoxic horse serum (Wellcome 474).] 
All of the above animals and most of those which appear upon the 
subsequent pages of this bulletin were first used to test the strength 
of the diphtheria antitoxin bought on the open market in accordance 
with the law of Juty 1, 1902. 
The following series of guinea pigs were given small quantities of 
antitoxic horse serum, some subcutaneously and come intraperitone- 
ally, in order to compare the sensitizing action by these two methods 
of inoculation. At the second injection they were all given 6 c. c. 
of normal horse serum into the peritoneal cavity. 
G. P. No. 276. Six c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Dead in 25 minutes. 
[Previous treatment: 17 days prior, inoculated subcutaneously with - 2 -^o c. c. antitoxic 
horse serum (Natl. V. 14).] 
G. P. No. 277. 
Do. 
Dead in 30 minutes. 
G. P. No. 278. 
Do. 
Dead in 55 minutes. 
G. P. No. 279. 
Do. 
Symptoms; recovered. 
G. P. No. 280. 
Do. 
Symptoms; recovered. 
G. P. No. 281. 
Six c. c. 
normal horse serum (r 
Symptoms; recovered. 
[Previous, treatment: 17 days prior, - 2 ho c - c - antitoxic horse serum (Natl. V. 14) 
injected into the peritoneal cavity.] 
G. P. No. 282. 
G. P. No. 283. 
G. P. No. 284. 
G. P. No. 285. 
Do. Dead in 23 hours. 
Do. Symptoms; recovered. 
Do. Dead in 60 minutes. 
Do. Symptoms; recovered. 
From the above series it will be seen that guinea pigs may be 
rendered as susceptible by intraperitoneal as by subcutaneous 
inoculations. 
Finally, in order to demonstrate without doubt that neither anti- 
toxin nor diphtheria toxine plays any part in this action, and to show 
that this action is a property of normal horse serum, we treated a 
number of guinea pigs giving them at both the first and second 
injection fresh normal horse serum, with the following results: 
G. P. No. 101. Three c. c. normal (roan) horse serum injected into the peritoneal cavity. 
Dead in 35 minutes. 
[Previous treatment: 55 days prior, inoculated subcutaneously with 2 |o c - c - normal 
horse serum (Jane).] 
