MILK AS A FACTOR IN THE CAUSATION OF DISEASE. 
107 
qualities of the milk by either killing the bacteria or lessening 
their vitality so that a long time is required before they can be¬ 
gin to multiply. (Year Book Dept. Agr., 1896.) 
It must be remembered, however, that the pasteurization or 
sterilization of milk is not of itself an advantage to milk. It is 
undertaken simply for the purpose of destroying the activity of 
that which is foreign to milk and which finds its way into milk 
either during or after milking. Milk from healthy cows is of 
itself absolutely pure, and but for the entrance of foreign organ¬ 
isms would keep indefinitely. It follows, then, that an effort 
should be made to prevent the entrance of these foreign mat¬ 
ters. Much can be done in this way—and for their own protec¬ 
tion dairymen ought to do as much as possible and go as far as 
practicable in this direction. 
Some of the principal pathogenic micro-organisms found in 
milk are those of tuberculosis, typhoid fever, cholera, diphtheria, 
scarlet fever, puss cocci, streptococci, pneumococci, etc. The 
most important of these are probably the specific organisms of 
tuberculosis, typhoid, cholera, diphtheria and scarlet fever. The 
first two have each their own peculiarities which make them 
specially important. Tubercle bacilli because they are carried 
from the cow direct, and come into the milk when present by 
way of the udder ; the typhoid fever bacilli because it multiplies 
rapidly in milk at ordinary temperature, so that once it finds its 
way into milk it will multiply rapidly and become a serious 
source of danger. As a precautionary measure, then, the great¬ 
est care should be exercised in using water for washing cans and 
other utensils to make sure that there is no possibility of con¬ 
tamination from this source. A most interesting illustration of 
the way in which typhoid fever is spread by the use of infected 
milk is reported to have occurred at Marlybone, where a farm 
hand was suffering from typhoid fever. A large number of per¬ 
sons taking milk from this farm became sick. The outbreak of 
fever following from house to house appearing in those houses 
supplied from this farm, and missing the intervening houses, so 
that in a certain street all those families that had been in the 
