50 
THE INFLUENCE OF LARGE QUANTITIES IN RENDERING GUINEA PIGS 
SUSCEPTIBLE. 
The guinea pigs in the following series were first used as controls 
to show that the injection of large quantities of horse serum into 
the peritoneal cavity produces no effect. They were subsequently 
injected with horse serum again in large quantities into the peri- 
toneal cavity to determine their susceptibility : 
G. P. No. 296. Six c. c. normal horse serum (roan) injected into the peritoneal cavity. 
Symptoms; recovered. 
[Previous treatment : 14 days prior, 6 c. c. donkey serum injected into the peritoneal 
cavity.] 
G. P. No. 297. Do. 
G. P. No. 298. Same injection. No symptoms. 
[Previous treatment: 14 days prior, 6 c. c. normal horse serum (Sp.) injected into the 
peritoneal cavity.] 
G. P. No. 299. Do. Symptoms; recovered. 
G. P. No. 300. Same injection. Symptoms; recovered. 
[Previous treatment : 22 days prior, 6 c. c. antitoxic horse serum (Natl. IX. 19) injected 
into the peritoneal cavity.] 
G. P. No. 301. Do. 
G. P. No. 302. Same injection. Symptoms; recovered. 
[Previous treatment : 14 days prior 6 c. c. antitoxic horse serum (Natl. V. 14) injected 
into the peritoneal cavity.] 
G. P. No. 303. Do. Symptoms (?) 
G. P. No. 304. Same injection. Dead in 65 minutes. 
[Previous treatment: 14 days prior 6 c. c. antitoxic horse serum (Natl. VIII. 18) 
injected into the peritoneal cavity.] 
G. P. No. 305. Do. Dead in 95 minutes. 
G. P. No. 306. Same injection. Symptoms; recovered. 
[Previous treatment : 14 days prior, 3.5 c. c. antitoxic horse serum (NYBH 10B Gibson) 
injected into the peritoneal cavity.] 
G. P. No. 307. Same injection. Dead in 48 minutes. 
[Previous treatment : 14 days prior, 2 c. c. antitoxic horse serum (NYBH 13C Gibson) 
injected into the peritoneal cavity.] 
G. P. No. 308. Same injection. Dead in 43 minutes. 
[Previous treatment: 14 days prior, 3 c. c. antitoxic horse serum (Alex. A211) injected 
into the peritoneal cavity.] 
G. P. No. 309. Same injection. Symptoms; recovered. 
[Previous treatment: 14 days prior, 6 c. c. antitoxic horse serum (Natl. IX. 17) injected 
into the peritoneal cavity.] 
G. P. No. 310. Do. Symptoms; recovered. 
It is plain, therefore, that guinea pigs may be rendered susceptible 
by the injection of large amounts of horse serum into the peritoneal 
cavity. We have seen, in another part of this bulletin, that these 
animals may also be rendered susceptible by the injection of large 
amounts into the subcutaneous tissue. 
We believe, however, that guinea pigs are rendered more suscep- 
tible by the injection of the toxine-antitoxin mixture than by the 
horse serum alone. 
