462 
eight hours at 37° C. In the boiled milk used as a control the bac- 
teria under the same conditions appear singly or in very short chains. 
Care was taken to break up all clumps in the suspensions used to 
inoculate both the raw and the boiled milk. 
Vigorous shaking also gave definite results, plainly proving that 
agglutination is one of the factors that cause an apparent decrease 
in the number of bacteria. 
The agglutinated bacterial clusters were shaken asunder by either 
one or both of the following methods, stated in each table: 
1. Vigorous shaking of the milk for about five minutes in a glass- 
stoppered cylinder. 
2. Drawing the suspension in and out a number of times through a 
papillary pipette, the end of which is broken off square and closely 
applied to the bottom of a test tube. 
Table No. 9. — Milk from healthy cow (No. 2) inoculated 1 § hours after milking . 
[Organisms from 24-hour agar cultures. Controls, same milk heated to boiling.] 
Colonies per 
loop at once 
after inocu- 
lation. 
Colonies per 
loop after 8 
hours at 
37° C. mod- 
erate shak- 
ing. 
Colonies per 
, loop after 8 
hours at 
! 37° C. after 
vigorous agi- 
i tation and 
1 mixing with 
, pipette. 
B . typhosus in raw milk 
5,620 
9,540 
4,660 
4,850 
2,600 
8, 100 
17 
2,640 
a b 1,000,000 
,3,810 
ab 200,000 
9,720 
a b 1,500,000 
45 
9, 720 
B. typhosus, control 
Staphylococcus pyogenes aureus in raw milk 
5,610 
Staphylococcus pyogenes aureus control _ 
B. coli in raw milk 
° b 100, 000 
B. coli, control. 
Original milk 
a Innumerable. & About. 
Table No. 10 . — Milk from healthy cow (No. 2) inoculated l\ hours after milking. 
[Controls, same milk heated in Arnold sterilizer to 100° C. for 10 minutes. Organisms used were 
from 24-hour agar cultures.] 
Bacteria per 
loop at once. 
Bacteria per 
! loop after 8 
hours at 37° 
C., tube 
moderately 
shaken. * 
Bacteria per 
loop after 8 
hours at 37° 
C., culture 
vigorously 
agitated 5 
minutes and 
mixed with 
a pipette. 
B. lactis aerogenes in raw milk 
1,200 
1,200 
3,440 
2,160 
- 2,120 
2,660 
4 
4.400 
(°) 
4.107 
(°) 
1.220 
30,000 
6 
14,000 
B. lactis aerogenes, control. 
B. typhosus in raw milk 
7,560 
B. typhosus, control. T 
Staphylococcus pyogenes aureus in raw milk 
Staphylococcus pyogenes aureus, control 
Original milk 
2,070 
^Innumerable. 
