36 Dairy Bacteriology. 



that had been pastured in a meadow was partially milked 

 out of doors. During the operation a covered glass dish 

 containing sterile gelatin was exposed for sixty seconds 

 underneath the belly of the cow in close proximity to the 

 milk pail. The udder, flank, and legs of the cow were 

 then thoroughly cleaned with water, and all of the pre- 

 cautions referred to before were carried out, and the milk- 

 ing then resumed. A second plate was then exposed in 

 the same place for an equal length of time; a control 

 also being made at the same time at a distance of ten 

 feet from the animal and six feet from the ground to as- 

 certain the germ contents of the surrounding air. 



From this experiment the following instructive data 

 were gathered. Where the animal was milked without 

 any special precautions being taken, there were 3,250 

 bacterial germs per minute deposited on an area equal to 

 the exposed top of a ten- inch milk pail. Where the cow 

 received the precautionary treatment as suggested above, 

 there were only 115 germs per minute deposited on the 

 same area. In the plate that was exposed to the sur- 

 rounding air at some distance from the cow, there were 

 sixty- five bacteria. This indicates that a large number 

 of organisms from the dry coat of the animal can be kept 

 out of milk if such simple precautions as these are in- 

 stituted. 



Another method of exclusion is to use a milk pail hav- 

 ing a partially closed top that will prevent the introduc- 

 tion of a large part of the dirt. 



Still another method that has much to recommend it, 

 is passing the milk through a hand separator immedi- 

 ately. This not only removes nearly all of the suspended 

 particles oi; foreign matter, such as dirt and filth of vari- 

 ous kinds, 1 but it eliminates a large part of the bacteria 



1 Backhaus (Milch Ztg., 26: 358, 1897) found that 95.6 per cent, of 

 impurities were removed by centrifugal separation. 



