class of people.

The larger cities have also recognized the impossibility of
requiring the tuberculin test of all cattle furnishing milk.
Pasteurization remains the only safeguard, and it is probable that
within a short time all the larger cities will require the
pasteurization of all milk, except that produced under strict
supervision.

As previously mentioned heating causes certain changes in milk. In
the treatment of market milk it is desirable to use as low
temperatures as will suffice to destroy the disease-producing
bacteria. It is fortunate that temperatures that will insure this
result have little effect on the milk. The temperatures now
recommended for pasteurization are as follows:

158 degrees F. for 3 minutes.
155 degrees F. for 5 minutes.
152 degrees F. for 10 minutes.
148 degrees F. for 15 minutes.
145 degrees F. for 18 minutes.
140 degrees F. for 20 minutes.

In actual practice the milk is heated to 145 degrees for 25 to 30
minutes. The acid-forming bacteria are not completely destroyed and
the pasteurized milk as a rule will undergo the same type of
fermentation as raw milk. It is, however, deemed essential that all
pasteurized milk be sold as such; that it be delivered to the
consumer within twenty-four hours after pasteurization and that no
milk be pasteurized a second time.

The continuous pasteurizing machines have the disadvantage that a
small portion of the milk passes through so quickly that all
pathogenic bacteria therein might not be destroyed, (p. 131). This
has led to the use of the "holding" process in which the milk is
heated to the desired temperature and then placed in tanks where it
remains at this temperature for any desired time. Every portion is
thus treated in a uniform manner.

If the milk is bottled after pasteurization, there remains
opportunity for reinfection, possibly with typhoid bacilli.
Pasteurization in the final container, the bottle, is being
recommended. This is possible only when a special bottle is used
with a metal cap lined with paper.

=Milk distribution.= Until within recent years in the cities and at
present in smaller towns, milk is largely retailed from cans which
are carried on the wagons or are kept in stores. This exposes the
milk to contamination from street dust and from the container
furnished by the consumer. It is well recognized that every utensil
with which milk is brought in contact adds more or less bacteria to
it, and the