478 
In the freezing experiments a small quantity of the milk was 
frozen solid by a mixture of salt and ice and kept in this condition 
for the periods stated. It was then cautionsly thawed and inoculated 
with the micro-organisms to be tested. 
The reason for selecting the temperatures used in Table Xo. 20, viz, 
55° C. and 65° C., was to differentiate the true bactericidal from the 
agglutinating substances, based upon similar work upon blood serum. 
Table No. 20. — ILilk from a healthy cow (No. 2) inoculated tivo hours after 
milking. 
Bacteria 
per loop at 
once after 
inocula- 
tions. 
Bacteria 
per loop 
after 8 
hours 
at 37° C. 
B. typhosus in milk first frozen 10 minutes 
(a) 
800 
B. t^'phosus in milk heated to 60° C. 20 minutes 
8,000 
12,000 
B. typhosus in milk heated to 80° C. 20 minutes 
18,000 
a b 380, 000 
B. typhosus in the whole raw milk 
3,500 
1, 200 
B. typhosus in sterilized milk (control) 
16,000 
a b 160, 000 
B. lactis aerogenes in milk first frozen 10 minutes 
10,000 
j 1,700 
B. lactis aerogenes in milk heated to 60° C. 20 minutes 
11, 000 
a b 50, 000 
B. lactis aerogenes in milk heated to 80° C. 20 minutes 
20,000 
I a b 400, 000 
B. lactis aerogenes in the whole raw milk 
5,400 
33 
B. lactis aerogenes in sterilized milk (control) 
36,000 
a 6 500, 000 
Original milk 
19 
I ^ 
“ Innumerable. '’About. 
Table No. 21. — milk from healthy cow (No. 2) inoculated two hours after 
milking. 
[24-hour culture used in each case.] 
B. typhosus in raw milk untreated 
B. typhosus in milk heated to 55° C. 30 minutes 
B. typhosus in milk heated to 65° C. 30 minutes 
B. typhosus in milk boiled 1 minute 
B. lactis aerogenes in raw milk untreated 
B. lactis aerogenes in milk heated to 55° C. 30 minutes 
B. lactis aerogenes in milk heated to 65° C. 30 minutes 
B. lactis aerogenes in milk boiled 1 minute 
Original milk 
Colonies 
per loop 
at once 
after 
inocu- 
lation. 
Colonies per loop after 
10 hours at 37° C. 
Shaken. 
Vigorously 
agitated. 
1,070 
1,960 
4,300 
1,350 
2,400 
17,820 
960 
13,000 
1,150 
(“) 
820 
12, 000 
15,000 
1,500 
(a) 
400 
(“) 
950 
(«) 
2 
18 
1 
“ Innumerable. 
'’About. 
