tructive experiments of Fraser[35] who
found that the actual amount of dirt dislodged from udders of apparently
clean animals during the milking process was three and one-half times as
much as when the cow's udders were washed. From udders visibly polluted
one ounce of such filth was removed in 275 pounds of milk, while from
cows whose udders had been washed, the same amount of dirt was
distributed through 24,030 pounds.

Fraser observed as a result of 420 examinations that the average germ
content of 4-inch culture dishes under clean but unwashed udders was
578, while under washed animals it was reduced to 192. From numerous
tests made in the writer's laboratory, it is evident that the germ
content of the milk in the pail is increased from 20,000-40,000 bacteria
_per minute_ during the milking period. By far the larger part of this
pollution can be easily prevented by cleaning and dampening the udder.

_5. Diminishing exposed surface of pail._ The entrance of organisms into
the milk can be greatly reduced by lessening the area of the milk pail
directly exposed to the dust shower. A number of so-called sanitary or
hygienic milk pails have been devised for this purpose. In one case the
pail is smaller at the top than bottom, but in most of them the common
form is kept and the exposed area is lessened by means of a cover, the
milk being received through a narrower opening. In some cases, strainers
are also interposed so as to remove more effectually the coarse
particles. It is necessary to have these covers and strainers
constructed in such a way so they can be easily removed and cleaned.

[Illustration: FIG. 10. Sanitary milk pails designed to diminish the
introduction of hairs, scales, dirt, etc., into milk.]

Stocking tested one of these pails (A, Fig. 10) and found that 63 per
cent of the dirt and 29 per cent. of the bacteria were prevented from
passing into the milk. Eckles examined one in which the germ content was
found to be 3200 per cc. as against 43200 per cc. in a common open
pail. This milk did not sour until it was 64 hours old in the first case
while in the latter it curdled in 43 hours.

~Air in barn.~ The atmosphere of the barn where the milking is done may
frequently contribute considerable infection. Germ life is incapable of
development in the air, but in a dried condition, organisms may retain
their vitality for long periods. Anything which contributes to the
production of dust in the stable and ai