284 MILK AND THE PUBLIC HEALTH CHAP. 



type of milking-machine. It is true that milking-machines 

 have been tested by bacteriologists, and reported upon favour- 

 ably by some although others have reported adversely, but in 

 such hands cleansing would be thorough and very different 

 from the routine cleansing of actual daily use. 



The careful report of Woll and Humphrey l may be quoted 

 as an example of such an investigation. They tested the 



1 



FIG. 25. Milking Machine. To show method ot cleaning the machine and its connections. 



Burrell- Lawrence -Kennedy Cow Milker (B. L. K. Milker). 

 Forty separate trials were made, and the 29 cows of the 

 University herd were milked continuously by the machine for 

 an average of 26 weeks. The machine acts by suction, in 

 imitation of the sucking of the calf. The air is partially 

 exhausted by means of a vacuum pump from a tightly covered 

 milk pail, which is connected by rubber tubing with a system 

 of piping extending in front of the cows' stalls. The milk 

 pail is connected with the cow's udder by means of a rubber 



1 Wisconsin University Agricultural Experiment Station, 1909, Research 

 Bulletin No. 3. 



