122 STORRS AGRICULTURAL EXPERIMENT STATION 

PIG 446, 
methods used, the bacteria accumulating in the tubes became 
more and more abundant as time went on. Of the methods which 
were efficient in sterilizing the tubes the formalin treatment 
was the most promising since it served to preserve the rubber 
as well as to sterilize the tubes. As previously stated, the steam 
sterilizing was not feasible because of its injurious effect on 
the rubber. At this point it was decided to return to the for- 
malin treatment. 
For the experiments given in Table 31, the tubes were treated 
in a formalin solution as already described in connection with 
Table 28, but in this case a somewhat stronger solution was 
used; 3% per cent of formalin being used instead of 2% in 
order to make sure that the tubes should be thoroughly ster- 
ilized between milkings. This ‘treatment proved to be very 
