_3. Clarification in separator._ Within recent years the custom has
grown of clarifying milk or removing the visible dirt by passing the
milk through a centrifugal separator the cream and skim milk being
remixed after separation. This process naturally removes the solid
impurities as dirt, hairs, epithelial scales and cells, also some of the
casein, making what is known as centrifuge slime. This conglomerate mass
is incomparably rich in germ life and the natural inference would be
that the bacterial content of the milk would be greatly reduced by this
procedure. Eckles and Barnes[31] noted a reduction of 37 to 56 per cent.
of the bacteria but others have failed to observe such reductions.[32]
This condition is explained by the more thorough breaking up of the
bacterial masses in the process, thus apparently not reducing them in
numbers.

It is somewhat surprising that in spite of the elimination of much
organic matter and bacteria, such clarified milk sours as rapidly as the
untreated product.[33]

The mechanical shock of separation ruptures the clusters of fat globules
and so delays creaming and also lessens the consistency of cream derived
from such milk. This practical disadvantage together with the increased
expense of the operation and the failure to materially enhance the
keeping quality of the product outweigh the advantage which might come
from removal of solid impurities which can be largely accomplished on
the farm by efficient straining.

_4. Washing the udder._ If a surface is moist, bacteria adherent to it
cannot be dislodged by ordinary movements. Thus the air over
snow-covered mountains or oceans is relatively devoid of germ life. The
method of moistening the udder is applied with success to the hairy coat
of the animal thus subserving the double purpose of cleaning the animal
and preventing in large measure the continual dislodgment of dust
particles. After these parts have been well carded to remove loose hairs
and dirt particles, the skin should be thoroughly moistened with clean
water and then wiped. It has been urged that this procedure lessens the
yield of milk but Eckles[34] concludes from experiments that when the
animal becomes accustomed to this treatment, no noticeable change in
amount of milk or butter-fat is produced.

The effectiveness of this method in reducing the actual amount of dirt
and filth introduced into the milk as well as the great diminution in
germ life is shown by the ins