bovine tuberculosis is hardly ever transmitted to grown persons and seldom to children. Neither is it hereditary. Nevertheless, wherever it is possible to have the herd tested with tuberculin, segregating, if not killing, the animals which show by reaction that they are somewhat tuberculous, it should be done. Milk from such cows should always be pasteurized.
Milk as a Disease Carrier.—A greater danger lies
in the fact that, warm as it comes from the cow, milk
is an ideal medium for human disease germs to grow
in, and may thus become a great conveyor of such
germs. For this reason it is of the greatest importance
that the milkers are healthy and clean, that the udders
and teats be free from dirt, and the milk pail covered
as far as possible; the barn must be clean, and every
source of infection excluded. This fact also points to
the advisability of pasteurization. On page 23 a chart
is shown, published by the Toronto Board of Health
and indicating the temperatures at which various germs
of disease are made harmless.
Bacterial Count.—The test for clean milk now mostly
used is the "Bacterial Count," the number of bacteria—or
rather colonies of bacteria—found in a cubic
centimeter of the milk. It would be better if the nature
or quality of the bacteria could be taken into consideration
as well as the quantity, but that being as yet
impracticable, the next best thing is to depend upon
the number. Ordinary good milk often contains hundreds
of thousands of bacteria in a cubic centimeter,
but where the greatest cleanliness is observed the
number may be less than 1,000.
Certified Milk is now sold in many cities which, according
to varying city ordinances, is guaranteed to
