Ko REPORT OF DEPARTMENT OF BACTERIOLOGY OF THE 
ing are entirely different. With the open pail.the germ con- 
tent depends mainly on the degree of cleanliness of the indi- 
vidual cow while with the milking machine the results turn 
mainly on the germ content of the rubber tubes through which 
the miik is conducted. 
From this point the comparison between the results obtained 
from hand and machine milking was discontinued and the 
study was directed toward the influence of variations in hand- 
ling the machine upon the germ content of the resulting milk. 
Parallel with this study of the effect of variations in handling 
upon the product of the milking machine a study is being made 
of the influence of various factors upon the germ content of 
hand-drawn milk. It is evident that the production of milk 
with a low germ content will be accompanied by an increased 
cost of production. When both of these methods of milking 
are reduced to standard conditions a comparison of the cost 
of production of milk of approximately the same germ content 
by each method will be of decided economic interest. 
In the preceding work the examination of the effect of the 
Globe machine was restricted to the first pair of cows to which 
the machine was applied at each milking. This was done to 
avoid the influence of accidental contamination of the machine 
in milking other cows. 
The marked increase in germ content which the milk received 
in passing through the machine suggested that the machine 
in turn might be partially cleaned by being used in the milking 
process. This point was determined by examining the milk of 
three successive pairs of cows which were milked by the same 
Globe machine. The results of these examinations are given in 
Table II. 
