MILKING MACHINES 121 

Fic. 44a—Plates showing numbers of bacteria in water used for rinsing 
inside of rubber tubes which were treated with borax solution, .1cc. 
and .5cc. of rinse water used for plates. 
A few of the experiments in Table 31 show a smaller germ 
content for the machine drawn milk than for the hand drawn 
milk, but in most of the tests the germ content of the machine 
milk is considerably higher than for that drawn by hand. In 
some cases the difference is very striking. Evidently this treat- 
ment did not keep the machines sterile. 
SEVENTH TREATMENT OF THE MACHINES. 
Thus far the sterilizing in steam and the treatment of the 
tubes in the formalin bath are the only methods which kept 
the tubes in a satisfactorily sterile condition. In the other 
