20 BULLETIN 642, U. S. DEPARTMENT OF AGRICULTURE. 
EXPERIMENT NO. 5. (COWS AND FLOOR DIRTY, MANURE REMOVED WEEKLY, 
UTENSILS STERILIZED.) 
This experiment was conducted under the same conditions as Ex- 
periment No. 2. Having determined the essential factors necessary 
for the production of fresh milk of low bacterial content, it was 
considered advisable to reproduce the original conditions in order to 
check the three factors again. Consequently, in the experiment the 
cows were allowed to get dirty and the manure was removed only 
once a week, but the other conditions of the barn were not changed. 
The object was to determine the factor of dirty cows; therefore, the 
utensils were sterilized in order not to add another factor. The con- 
dition of the barn and of the cows is illustrated in figures 11 and 12, 
respectively. Particular attention is directed to the extremely large 
quantity of filth on the floor of the barn. 
During the experiment, which continued from April 11 to May 6, 
1916, 41 samples of milk were examined from both small-top and 
open pails. The average count of samples from the former was 
24.439, and from the latter 86,212 bacteria per cubic centimeter, as 
shown in Table 6. 
Fic. 11.—Condition of barn during Experiment No, 5. 
