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APPLICATIONS OF BACTERIOLOGY tN EUROPE. 69 
two diseases which apparently also attack the cow and may be 
transmitted from the cow to man by means of milk. In re- 
gard to these two diseases, however, it must be stated that it 
is not as yet positive that they can be transmitted to man from 
a cow suffering from the diseases, although the evidence in our 
possession at the present time looks in that direction. Certain 
it is, however, that the milk may become contaminated from 
some secondary source with the germs of these diseases, and 
then the disease be transmitted to man. 
Typhoid fever and cholera and a variety of diarrhoeal dis- 
eases especially common in children are also transmitted by 
means of milk. In these cases, however, it appears that the 
contamination with the bacteria is always secondary. The 
cow herself does not suffer from these diseases, but bacteria 
from some source of contamination which get into the millx 
atter it is drawn from the cow may be the cause of them. 
These are the important facts in briefest outline, which have 
been determined in connection with dairy bacteriology and 
which have led to very great changes in dairy methods. 
APPLICATIONS OF SOME OF THESE FACTS. 
It is, of course, impossible to enumerate all of the minor 
changes in dairy management which have been produced in 
dairying through all civilized communities by knowledge of 
the facts above mentioned. The treatment of the cow, and 
the treatment of the milk from the very beginning to the time 
it is consumed by man, are modified in countless little details 
in accordance with the facts that are known. The general 
change that has been introduced is quite comprehensively ex- 
pressed by the statement that dairy methods have been so 
altered in the last ten years that the milk from a time imme- 
diately preceding the milking to the time when it is delivered 
to the consumer is carefully guarded against contamination. 
Farmers in civilized communities have learned the chance and 
the danger of such contamination, and they have therefore 
been slowly but effectually adopting methods of protecting 
the milk. 
This occurs in the first place in the stable. Recognizing 
that the cow is one of the chief sources of trouble, attention is 
given to her. She is kept cleaner than was thought necessary 
_a few years ago. Her udder is in many cases washed with 
warm water; the teats may be moistened before milking, or 
s.—6 
