72 
TYPHOID FEVEE lY DISTEICT OF COLUMBLl. 
bulk of the milk sold in the District of Columbia last summer would, 
therefore, have been condemned according to the health regulations 
of Boston. 
Park finds that milk starting with 12,000 bacteria per cubic centi- 
meter in warm weather and 5,000 in cold weather, if quickly cooled 
to 46° F., and kept at that temperature, will, at the end of thirty-six 
hours, contain on an average less than 50,000 bacteria per cubic cen- 
timeter: and if cooled to 40° F., ^vill average less than its original 
number. Park states that : 
With only moderate cleanliness, such as can be employed by any farmer without 
adding appreciably to his expense, namely, clean pails, straining cloths, cans or 
bottles, and hands, a fairly clean place for milking, and a decent condition of the 
cow's udder and the adjacent belly, milk when first drawn will not average in hot 
weather over 30,000 and in cold weather not over 25,000 bacteria per cubic centimeter. 
Such milk, if cooled to and kept at 50° F., will not contain at the end of twenty-four 
hours over 100,000 bacteria per cubic centimeter. If kept at 40° F. the number of 
bacteria will not be over 100,000 per cubic centimeter after forty-eight hours. 
If, however, the hands, cattle, and barns are filthy, and the pails are not clean, the 
milk obtained under these conditions will, when taken from the pail, contain verA* 
large numbers of bacteria, even up to a million or more per cubic centimeter. 
Any intelligent farmer can use sufficient cleanliness and apply sufficient cold, with 
almost no increase in expense, to supply milk twenty-four to thhty-six hours old 
which will not contain in each cubic centimeter over 50,000 to 100,000 bacteria, and 
no milk containing more bacteria should be sold. 
THE KIND OF BACTERIA FOUND IN THE MILK. 
The kind of bacteria and the nature of the bacterial toxic prod- 
ucts in milk are more important from a public health standpoint 
than the number per cubic centimeter. We made no detailed quali- 
tative analysis of the milk samples, partly for lack of time and partly 
because it is possible by presumptive tests to determine whether 
a milk is contaminated with bacteria from manure, cow dimg, and 
other outside sources. This is done by the fermentation of sugar 
broth. 
It has been abundantly demonstrated (see reference to the litera- 
ture, p. 80) that the bacteria in milk, as it leaves the udder, largely 
consist of staphylococci, streptococci, and other pyogenic organ- 
isms. Xone of these bacteria ferment su^ar broth.. On the other 
hand, the colon bacdlus, including the entire group of lactic acid 
producers and many other organisms that gain entrance into the 
milk from cow dung, manure, dust, water, etc., cause active fer- 
mentation. We therefore possess a ready test for the approximate 
determination of the character and sources of the bacteria in milk. 
MacConkey states (see p. 80) that with ordinary care and cleanli- 
ness freshly dravm milk should not contain gas-forming organisms 
in 50 cubic centimeters. 
