DISEASE GERMS IN MILK 175 
contain the particular form of lactic bacteria mentioned on page 162 
which has the characteristic of being more vigorous, and making 
milk more acid than the ordinary lactic acid bacteria, and, there- 
fore, having in even greater degree this power of preventing the 
growth of other more mischievous organisms. The healthful 
properties ascribed to the alcoholic beverages mentioned on 
page 171 are probably due to the presence of the beneficent lactic 
acid bacteria. 
DISEASE GERMS IN MILK 
It has long been recognized that milk may be a distributer of 
disease. This general statement is disquieting, but the knowledge 
is of little use unless it can be made more definite. The subject 
can be made more intelligible if we notice what 
kind of diseases are thus distributed and how the Ge 
dangers arise. There are four definite diseases yx 
known to be distributed in this way, and, in es 
addition, a less definite type of intestinal trouble. 1G. 390-—The ty- 
Tuberculosis —This subject will be considered — phoid bacillus. 
in a separate chapter. 
Typhoid Fever-—Typhoid fever is produced by a well-known 
bacterium primarily inhabiting the human intestine (Fig. 30). 
Inasmuch as the cow is not subject to typhoid fever, milk, when 
freshly drawn, will never contain typhoid bacilli. This disease, 
therefore, bears quite a different relation to dairy matters from 
tuberculosis. Milk, if infected with tuberculosis bacilli, contains 
them when freshly drawn, and secondary infection is a matter of 
little significance. But fresh milk never contains typhoid bacilli, 
and if they are present in the milk, they come wholly from sec- 
ondary contamination. The chief sources of these secondary 
contaminations are: (1) Direct contact with persons who have or 
are recovering from the disease. It is well known that patients 
may, after recovery from this disease, carry around the living 
