451 
contain opsonic power." Our work shows that phagocytosis plays no 
essential role in the apparent reduction in the number of bacteria in 
fresh milk. 
It seems that the germicidal property of milk corresponds to a 
similar property of fresh blood serum. This makes it probable that 
the causes are numerous and complex. Further, it explains why the 
action is variable in different milks and in milk from the same cow 
at different times. It also gives us a clew as to why the action is to 
a certain extent specific. 
Although the germicidal property of fresh milk is feeble, it must 
be of value to the suckling. This self-evident fact emphasizes the 
importance of using fresh milk for artificial feeding. 
EXAMPLES OF THE GERMICIDAL ACTION. 
The following examples show that milk when fresh and raw actu- 
ally restrains the growth of bacteria as judged by the development 
of colonies upon agar plates. Whether the bacteria are restrained, 
destroyed, or clumped is not evident from such technique. 
This series shows the effect upon the growth of the common bac- 
teria that usually contaminate milk. These results show a restrain- 
ing, rather than a germicidal action, which varies with the tempera- 
ture. The reduction is more apparent from a study of our work with 
pure cultures ( vide infra ) . 
Table Xo. Y.— Milk from a healthy cow (No. 1 ). 
[Immediately after milking contained 400 bacteria per cubic centimeter.] 
Bacteria per cubic centimeter at different 
temperatures. 
ature, 16° to 15° C. 37° C. 
23° C. 
2 hours 430 
4 hours 100 450 350 
6 hours 350 600 2,100 
8 hours 450 300 345,000 
10 hours 500 350 1, 780, 000 
12 hours 400 300 32,800,000 
14 hours 500 400 75,500,000 
24 hours 5.000 2,000 Sour. 
36 hours 60.000 2,000 
48 hours 366,000 1.000 
SO hours 780.000 | 3,800 
72 hours 24,200,000 61,000 
84 hours 250,000,000 118.000 
96 tours 330,000.000 3.080.000 
108 hours 910.000,000 33,400.000 
120 hours , Sour. 192,000.000 
144 hours Innumerable 
a in fact Woodhead and Mitchell claim to have demonstrated opsonins in milk. Joum. of Path, 
and Bactr., vol. 11, 1906-7, p. 408. 
