366 Bacteria in Relation to Country Life 



It was thus evident that, while in the milk of the 

 high-grade dairy the total number of bacteria was 

 smaller, the hand-drawn milk was bacteriologically 

 superior to the machine-drawn milk in both cases. 



It was clear, also, that the method employed in clean- 

 ing the milking-machines namely, rinsing with water 

 containing some sal soda, and then washing with hot 

 water, was not adequate for eliminating the bacteria 

 from the rubber tubes of the machines. On taking the 

 rubber tubes and teat-cups apart, Stocking found the 

 interior of the long tube to be coated with decaying 

 milk. These tubes had become, therefore, nurseries for 

 various germs, particularly the more resistant forms. 

 The milk drawn through them naturally became filled 

 with bacteria. 



Scalding the machines by means of boiling water 

 pumped through them failed to achieve satisfactory 

 results. Steaming at atmospheric pressure for a half- 

 hour, or boiling the tubes in clean water for three 

 quarters of an hour, was insufficient for their steriliza- 

 tion. On the other hand, the boiling of the tubes in a 

 weak solution of borax, or their immersion in brine 

 solutions for several hours, proved effective. After the 

 brine treatment, the machine-drawn milk in Dairy 1 

 contained 327,412 and 153,629 bacteria per cubic centi- 

 meter, respectively, for the night and morning milking. 

 The corresponding samples of hand-drawn milk con- 

 tained 693,488 and 240,054 bacteria per cubic centimeter, 

 respectively. In Dairy 2, treatment with brine reduced 

 the bacterial content of the machine-drawn milk to 

 2,444 per cubic centimeter, while the corresponding 



