459 
It seems likely 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 animal 
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 bacteria that 
usually contaminate milk. These results show a restraining, rather 
than a germicidal action, which varies with the temperature. Actual 
reduction in numbers is more apparent from a study of our work with 
pure cultures (vide infra). 
Table No. 1. — Mil]z from a healthy coio (No. 1). 
[Immediately after milking contained 400 bacteria per cubic centimeter.] 
Time after milking. 
2 hours 
4 hours 
6 hours 
8 hours 
10 hours 
12 hours 
14 hours 
24 hours 
36 hours 
48 hours 
60 hours 
72 hours 
84 hours 
96 hours 
108 hours 
120 hours 
144 hours 
Bacteria per cubic centimeter at different 
temperatures. 
Room temper- 
ature, 16° to 
23° C. 
15° C. 
37° C. 
430 
100 
450 
350 
350 
600 
2, 100 
450 
300 
345,000 
500 
350 
1,780,000 
400 
300 
32,800,000 
500 
400 
75, 500, 000 
5,000 
60,000 
366.000 
780.000 
24, 200, 000 
250.000. 000 
330.000. 000 
910.000. 000 
Sour. 
2,000 
2,000 
1,000 
3,800 
61,000 
118,000 
3,080,000 
33,400,000 
192,000,000 
Innumerable. 
Sour. 
