435 
Bitter a believes that no milk should be sold in cities containing 
more than 50,000 bacteria per cubic centimeter. 
Park * * 6 * * states that any intelligent farmer can use sufficient cleanli- 
ness and apply sufficient cold with almost no increase in expense to 
supply milk twenty-four to thirty-six hours old which will not con- 
tain in the maximum over 50,000 to 100,000 bacteria per cubic 
centimeter, and that no milk containing more bacteria than this 
should be used. 
The above figures apply to standards that have been set on market 
milk. So far as milk for infant feeding and other clinical purposes 
is concerned, the standard established by Coit of 10,000 bacteria per 
cubic centimeter as a maximum seems, by almost unanimous consent, 
to be the best. Some communities have adopted a second grade 
of milk known as “ inspected” milk from tuberculin-tested cattle 
and obtained under cleanly conditions, and not containing over 
100,000 bacteria per cubic centimeter. 
The number of bacteria, therefore, allowable in milk depends upon 
the purposes for which it is used and varies somewhat with the 
locality. It is evidently easier to obtain milk containing fewer 
bacteria in small communities with a near-by supply and in cold 
climates, than it is in larger cities with inevitable delays in trans- 
portation or in southern latitudes. 
As a general rule it may be stated that 11 certified ” milk should never 
exceed 10,000 bacteria per cubic centimeter, “inspected” milk not 
over 100,000, and health officers should aim to keep the general 
milk supply below the 100,000 mark. 
THE PRACTICAL VALUE OF BACTERIAL EXAMINATIONS OF MILK. 
The activities of our health officers were at first directed almost 
exclusively to the prevention of sophistication of milk, detected by 
chemical methods, to the neglect of the valuable information obtained 
from bacterial examinations. 
The addition of water to milk and the extraction of cream are 
fraudulent practices, but, as a rule, have only a secondary bearing 
upon the public health. The bacteriologic examination of milk 
gives us a clew to the cleanness of the methods employed, the tem- 
perature, and the age of the milk. The health officer wffio has the 
advantage of bacteriologic assistance knows that the milk of dairies 
containing excessive numbers of bacteria is dirty, old, or warm. 
° Bitter, H.: Versuche fiber das Pasteurisiren der Milch. Zeit. f. Hyg., vol. 8, 
1890, p. 240. 
6 Park, 'William H., and Bebb, Rose A.: The great bacterial contamination of the 
milk of cities. Can it be lessened by the action of health authorities? N. Y. Univ. 
Bull. Med. Sci., vol. 1, 1901. 
