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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 Xo. 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 

 21.439, and from the latter 86,212 bacteria per cubic centimeter, as 

 shown in Table 6. • 



Fig. 11. — Condition of barn during Experiment; No, o, 



