53 
Table No. 46. — Effect of repeated small injections upon sensitive guinea pigs — Con. 
G.P. 
No. 
First injection. 
Inter- 
val in 
days. 
Second injection. 
Result. 
9186 
0.23 c. c. toxine No. 7+1/270 c. c. 
antitoxic horse serum (Mul. 
2362) . 60 days later 10 injec- 
tions 0.001 c. c. each, covering 
period of 20 days. 
11 
0.05 c.c. normal horse (roan) se- 
rum into brain. 
Severe symptoms. 
91.57 
0.23 c. c. toxine No. 7+1/290 c. c. 
antitoxic horse serum (Cutter 
1856) . 60 days later 10 injec- 
tions 0.001 c. c. each, covering 
period of 20 days. 
11 
' 0 c. c. normal horse (roan) .se- 
rinn subcutaneously. 
Slight symptoms. 
ATTEMPTS TO IMMUNIZE SENSITIVE GUINEA PIGS BY RE- 
PEATED INJECTIONS OF HEATED SERUM. 
In the following series sensitized guinea pigs were injected with 1 c. c. 
of normal horse serum heated to 100° C. for one hour. The serum was 
first diluted in the proportion of 1 part to 3 of water-to prevent coagula- 
tion. The 1 c. c. of the mixture injected into the guinea pigs repre- 
sents, therefore, 0.25 c. c. of horse serum. The pigs received from 20 to 
25 injections subcutaneously. They therefore received a total amount 
of 5 to 6 c. c. of normal horse serum. It is evident from the table that 
these injections failed to materially modify the susceptibility of the 
guinea pigs. 
Table No. 47. — Effect of heated serum upon sensitive guinea pigs. 
G.P. 
No. 
First injection. 
Inter- 
val in 
days. 
Second injection. 
Result. 
9197 
0.23 c. c. toxine No. 7+1/400 c. c. 
antitoxic horse serum (Schr. 
II). 62 days later 20 injec- 
tions 1 c. c. daily normal 
horse (roan) serum heated 
100° C. 1 hour, subcutane- 
ously. 
alO 
0.2 c. c. normal hor.se (roan) se- 
rum into brain. 
- 
Dead in 10 minutes 
9179 
0.23 c. c. toxine No. 7+1/540 c. c. 
antitoxic horse serum (Mul. 
2443) . 62 days later 22 injec- 
tions 1 c . c . daily heated serum. 
8 
6 c. c. normal horse (roan) se- i 
rum intraperitoneally. i 
Severe symptoms. 
9180 
i 
0.23 c. c. toxine No. 7+1/680 c. c. 
antitoxic horse serum (Mul. 
2443) . • 62 days later 25 in jec- 
tionslc.c. daily heated serum. 
4 
6 c. c. normal horse (roan) se- j 
rum subcutaneously. 
Marked symptoms. 
9191 
0.23 c. c. toxine No. 7+1/400 c. c. 
antitoxic horse serum (Mul. 
2358) . 62 days later 24 injec- 
tionslc.c. daily heated serum. 
6 
• 
Very severe symp- 
toms. 
a'After last, injection. 
