60 
We noticed that the subcutaneous injection of horse serum into 
guinea pigs sometimes occasions a local reaction, as indicated by 
edema at the site of inoculation, but the above guinea pigs Xos. 10S 
and 110. which received a large number of injections, seemed to react 
less each time. 
We give below a series of 11 guinea pigs injected with large quan- 
tities of horse serum at irregular intervals. It is plain from these 
experiments that a rather high degree of immunity may be induced 
by repeated injections. 
G. P. Xo. 4101. One c. c. antitoxic horse serum Xatl. YIIL 17) injected into the perito- 
neal cavity. Symptoms: recovered. 
[Previous treatment: 37 days prior, inoculated subcutaneously with 0.22 c. c. toxine 
Xo. 7~r2To c - c - antitoxic horse serum (Alex. 190 .] 
8 days later. 1 c. c. antitoxic horse serum Xatl. YIII. 17 into peritoneal cavity. Symp- 
toms. less severe. 
16 days later, 6 c. c. into peritoneal cavity. Xo symptoms. 
6 days later. 6 c. c. into peritoneal cavity. Symptoms. 
9 days later. 6 c. c. into peritoneal cavity. Xo symptoms. 
34 days later. 6 c. c. into peritoneal cavity. Symptoms (?(. 
20 days later. 6 c. c. antitoxic horse serum Xatl. YIII. 18 into peritoneal cavity. Xo 
symptoms. 
G. P. Xo. 4.530. Six c. c. antitoxic horse serum Xatl. YIII. 17 injected into the peritoneal 
cavity. Symptoms: recovered. 
[Previous treatment: 10 days prior, inoculated subcutaneously with 0.19 c. c. toxine 
Xo. 7 — 1 unit antitoxic horse serum Standard B27 .] 
15 days later. 6 c. c. antitoxic horse serum Xatl. YIII. 17 into peritoneal cavity. 
Symptoms. 
2 days later, 6 c. c. into peritoneal cavity. Eestless. 
6 days later, 6 c. c. into peritoneal cavity. Symptoms (?). 
9 days later. 6 c. c. into peritoneal cavity. Symptoms (?). 
33 days later. 6 c. c. antitoxic horse serum Xatl. YIII. IS 1 into peritoneal cavity. Xo 
symptoms. 
21 days later. 6 c. e. into peritoneal cavity. Xo symptoms. 
G. P. Xo. 4532. Six c. c. antitoxic horse serum Xatl. YIII. 17 injected into the peritoneal 
cavity. Symptoms : recovered. 
[Previous treatment: 11 days prior, inoculated subcutaneously with 0.19 c. c. toxine. 
Xo. 7—1 unit antitoxic horse serum Standard B27).] 
14 days later, 6 c. c. antitoxic horse serum i Xatl. YIII. 17 into peritoneal cavity. Xo 
symptoms. 
8 days later, 6 c. c. into peritoneal cavity. Symptoms (?). 
9 days later, 6 c. c. into peritoneal cavity. Xo symptoms. 
34 days later. 6 c. c. antitoxic horse serum Xatl. YIII. 18 into peritoneal cavity. 
Symptoms: recovered. 
20 days later. 6 c. c. into peritoneal cavity. Symptoms: recovered. 
G. P. Xo. 4432. Six c. c. antitoxic horse serum (Xatl. YELL 17 injected into the peritoneal 
cavity. Xo symptoms. 
[Previous treatment: 7 days prior, inoculated subcutaneously with 0.002 c. c. toxine 
Xo. 7.] 
22 days later, 6 c. c. antitoxic horse serum (Xatl. YIII. 17) into peritoneal cavity. Xo 
symptoms. 
15 days later, 6 e. e. into peritoneal cavity. Symptoms. 
