32 
plates were grown at 37° C. for four days and the surface growth 
collected. 
The bacterial mass was frozen forty-eight hours at about 15° F., 
thawed at room temperature, and then ground with sand b}^ hand in a 
mortar and pestle for five hours, shaken vigorously half an hour, and 
again frozen eighteen hours. After again thawing, the fluid was diluted 
with salt solution and filtered through a Berkefeld filter. The clear 
filtrate gave a distinct coagulum with heat and acetic acid. 
All the other extracts were obtained by a similar process. In the 
case of the tubercle bacillus the bacterial mass was first washed three 
da}^s in running water to eliminate the soluble tuberculin as much as 
possible. 
B. coli. 
No. 
G.P. 
First injection. 
Interval. 
Second injection. 
Result. 
817 
5 c. c. colon extract, 
Days. 
35 
6 c. c. colon extract. 
Marked symptoms. 
819 
subcutaneously. 
1 c. c. colon extract, 
35 
intraperitoneall y . 
do 
Mild symptoms. 
818 
subcutaneously. 
do 
35 
6 c. c. colon extract. 
Marked symptoms 
820 
do 
35 
subcutaneously. 
do 
Slight symptoms. 
Mild symptoms. 
821 
do 
35 
6 c. c. colon extract. 
822 
0.5 c. c. colon extract. 
35 
intraperitoneally. 
6 c. c. colon extract. 
Mild symptoms. 
823 
subcutaneously. 
0.1 c. c. colon extract. 
35 
subcutaneously. 
6 c. c. colon extract. 
Slight symptoms. 
824 
subcutaneously. 
0.01 c. c. colon extract. 
35 
intraperitoneally. 
6 c. c. colon extract. 
Marked symptoms. 
825 
subcutaneously. 
0.005 c. c. colon extract. 
35 
subcutaneously. 
6 c. c. colon extract. 
Severe symptoms. 
subcutaneously. 
intraperitoneally. 
The hypersusceptibility induced by the colon extracts manifested 
itself by symptoms resembling those already described in the case of 
horse serum. The guinea pigs scratched at the mouth with their hind 
legs. Most of them showed evidences of respiratory embarrassment 
by quickened, labored, or irregular breathing. Many of the pigs lay 
over on their sides, which is a very common s 3 uiiptom. A few devel- 
oped jerk}" movements, but in no case was convulsion noted. The 
pigs looked quite sick and ill at ease, but gradually recovered, so that 
by next morning they seemed normal. 
Ten da}^s following the second injection of the extract all the above 
pigs were given 5 c. c. of a heavy emulsion of colon bacillus from 
24-hour old agar slants, but showed no symptoms, and remain in good 
condition. Three controls received the same injection and died in 
twelve hours. 
