DAIRY METHODS 



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by which the vacuum is made to draw through the tubes inter- 

 mittently, thus imitating natural milking. (Fig. 54.) This 

 draws the milk through the tubes to the can. Details of these 

 machines need not concern us here, but their efficiency in milk- 



FIG. 53 MILKING MACHINE 

 (United States Department of Agriculture) - ' 



ing is beyond question. It would seem that such a plan, which 

 carries milk directly from the teat to a sterilized can, without 

 contact with the air, would be almost ideal and would remove 

 practically all dirt contamination. All ordinary sources of 

 filth contamination are excluded by such milking machines, and 



