78 STORRS AGRICULTURAL EXPERIMENT STATION. 
brush such as is commonly used in dairy barns. This group 
of cows was then milked and samples from the two lots of milk 
taken as previously described. Table No. 23 shows the num- 
bers of bacteria that were found in the two kinds of samples 
taken in this way. 
A study of the column marked ‘‘ total bacteria’’ shows that 
there was very uniformly a higher number of bacteria in the 
milk drawn from the cows which had just been brushed than 
there was in the milk drawn from the cows which were milked 
before the brushing was done. These results are not surpris- 
ing to those who appreciate the fact that the hair and skin of 
the cow normally carry large numbers of bacteria. The dust 
and hair which are set free by the brushing must necessarily 
fill the air with bacteria in the vicinity of the cow and this dust 
will fall into the milk pail carrying bacteria with it, if the cow 
is milked before the dust has hada chance to settle. In expe- 
riment 13 there is practically no difference in the germ content 
of the milk from the two groups of cows. Experiment 12 is 
the only one where the milk from the unbrushed cows contains 
a higher germ content than does the milk from the brushed 
group. It is evident that this condition was caused by some 
unusual source of contamination of the milk from the un- 
brushed cows. With this one exception the evidence is prac- 
tically unanimous against the practice of brushing a¢ or just 
before the process of milking. The influence of the brushing 
is in most of the experiments quite marked upon both the acid 
producing and liquefying groups of bacteria. The following 
diagram shows the relative numbers of bacteria as given in the 
averages for the column marked ‘‘ total numbers’’ of bacteria. 
The cows used in these experiments were unusually clean and 
the amount of dust stirred up by the brushing was, therefore, 
Diagram showing the above averages for the total bacteria. 
Not brushed, 
Ne Tb U=) eV eye hy 9 MER eae a ek ee 
Increase due 
to brushing, 
