BACTERIAL EXAMINATION 375 
present time the commission suggests that the standard be gradually 
applied. 
Tuer BactTeRIAL EXAMINATION OF MILK 
The value of the bacterial examination of milk is somewhat depend- 
ent upon the application of the results and the opinions of those who are 
interpreting them. The Commission on Milk Standards regards the 
bacterial content as being due to dirt, temperature and age. The bac- 
terial examination, then is supposed to yield information bearing on 
these three factors. 
Initial Contamination. Milk is such an excellent medium for bace 
terla that the initial infection determines the number which will be 
present after a time. The factors which influence this may be men- 
tioned as follows: 
I. Cow 
a. Udder. 
6. Coat, ete. 
II. Barn Conditions 
III. Milker 
IV. Utensils 
a. Pails, cans, ete. 
b. Special apparatus 
1. Separator 
2. Clarifier 
3. Pasteurizer 
4. Cooler 
5. Bottler 
It is fairly well established that milk as it is excreted from the udder 
is not sterile. Harding and Wilson (1913) and other workers to whom 
they refer in their paper furnish much information to confirm this state- 
ment. An examination of 1230 samples from the udders of 78 cows 
showed an average of 428 bacteria per cubic centimeter. Evans (1916) 
studied 192 samples of milk from 161 cows in dairies which were widely 
separated. Three types of bacteria were found commonly present in 
milk from the five dairies which were studied: streptococci, staphy- 
lococci and bacilli. Streptococcus lacticus (Kruse) was not found in any 
of the samples. This author states that “there is a definite udder 
flora comprising bacteria which belong to parasitic types. It is not 
