COMPARATIVE STUDIES WITH COVERED MILK PAILS 95 
The milk from which these tests were inade was obtained 
by milking one group of five cows into the pail with the strain- 
er attachment and another group of five cows into a similar 
pail from which the strainer device had been removed. Sam- 
ples were then taken from the mixed milk of these two 
groups of cows and bacteriological determinations made as 
already described earlier in this bulletin. 
A study of Table 22 shows rather striking results in the 
germ content of the milk drawn into the pail with and without 
the strainer. In the first place it may be noticed that in eight 
of the experiments out of the twelve milk drawn through the 
strainer showed a higher germ content than the milk drawn 
at the same milking into the pail which had no strainer. In 
four of the experiments the results show a smaller germ 
content in the milk which passed through the strainer. The 
averages for these two series of experiments indicate a de- 
cided advantage in favor of using the pail without the strain- 
er. These average differences are strikingly illustrated by the 
diagram which is given in connection with Table 22. The milk 
drawn into the pail without the strainer contained on an aver- 
age but 73.5 per cent. of the number of bacteria which were 
found in the milk drawn into the pail which bore the strainer. 
These results indicate that better results can usually be ob- 
tained by using the pail without the strainer cloth. The 
larger germ content normally found in the milk drawn through 
the strainer is no doubt due to the fact that whatever dirt 
falls into the strainer is broken up and driven through into 
the milk by the succeeding streams of milk beating upon it 
as it rests on the strainer so that more bacteria actually be- 
came disseminated through the milk when the strainer is used 
than when the strainer is not used under the same stable 
conditions. It was also found that the milk drawn without 
the use of the strainer kept longer than that drawn through 
the strainer. An added advantage in using this pail without 
the strainer attachment is in its greater simplicity and the 
avoidance of having the extra parts to be washed each time. 
Strainer tests with the North covered pail. This pail fitted 
ready for use is shown in Fig. 34. The cover consists of a 
tin cover slightly raised in the center with a circular opening 
four inches in diameter in the middle. Two layers of fine 
strainer cloth are laid over the top of the pail and the cover 
put in place thus holding the strainer cloth in position. The 
opening in this pail is of practically the same size as that 
in the Stadtmueller pail. 
