,000 per cc. The
germ content of city milks increase rapidly in the summer months.
Park[44] found 250,000 organisms per cc. in winter, about 1,000,000 in
cool weather and 5,000,000 per cc. in hot summer weather. Knox and
Bassett in Baltimore report 1,500,000 in spring and nearly 4,500,000 in
summer. Eckles[45] studied milk under factory conditions. He finds from
1,000,000 to 5,000,000 per cc. in winter, and in summer from 15-30
millions.

~Bacterial standards for city supplies.~ It would be very desirable to
have a hygienic standard for city milk supplies, as there is a butter
fat and milk-solid test, but the wide spread variation in germ content
and the impracticability of utilizing ordinary bacterial determinations
(on account of time required) makes the selection of such a standard
difficult. Some hold, as Park, that such a standard is feasible. The New
York City Milk commission has set a standard of 30,000 bacteria per cc.
for their certified milk and 100,000 per cc. for inspected milk.
Rochester, N. Y. has attempted the enforcement of such a standard
(limit, 100,000 per cc.) with good results it is claimed while Boston
has placed the legal limit at 500,000 per cc. Quantitative standards
would seem more applicable to "certified" or sanitary supplies than to
general city supplies, where the wide range in conditions lead to such
enormous variations that the bacterial standard seems too refined a
method for practical routine inspection.

~Other tests.~ Any test to be of much service must be capable of being
quickly applied. The writer believes for city milk inspectors that the
acid test would serve a very useful purpose. This test measures the
acidity of the milk. There is, of course, no close and direct
relationship between the development of acidity and the growth of
bacteria, yet in a general way one follows the other at normal
temperatures. Where the temperature is kept rather low, bacterial growth
might go on without much acid development, but in the great majority of
cases a high degree of acidity means either old milk, in which there has
been a long period of incubation, or high temperature, where rapid
bacterial growth has been possible. Either of these conditions
encourages germ growth and thus impairs the quality of the milk.

The rapid determination of acidity may be made in an approximate manner
so as to serve as a test at the weigh-can or intake. The test is best
made by the use of the well known alkali