15 
Doctor Rosenau shows, as a result of many hundred bacteriologic 
examinations of the market milk of Washington made in the 
Hygienic Laboratory, that for the most part it is old, warm and 
dirty. In the summer of 1906 the market milk contained on an 
average of 22,134,289 bacteria per cubic centimeter, and was delivered 
at an average temperature of 16.5° C. During 1907 the average was 
11,000,000 bacteria per cubic centimeter, and temperature 14.2° C. 
The advantages of bacterial counts to the health officer and to the 
practical dairyman are pointed out. 
As a result of original investigations, Doctor Rosenau and Doctor 
McCoy demonstrate the causes of the phenomenon known as the ger- 
micidal property of milk. They show that the decrease in the num- 
ber of bacteria in fresh milk is for the most part apparent, not real, 
and further that the restraining action of milk can not take the place 
of cleanliness and ice, but may be taken advantage of in good dairy 
methods. 
Doctor Miller reviews the significance of leucocytes and strepto- 
cocci in milk and points out the unsatisfactory state of our knowledge 
concerning their sanitary significance. 
Doctor Mohler points out that probably the most important disease 
of cows from the standpoint of public health is tuberculosis, and that 
it is also the most prevalent. The German commission on tubercu- 
losis found over 10 per cent (6 out of 56) cultures of tubercle bacilli 
of human origin, virulent for cattle. In a similar series of tests con- 
ducted by the British Royal Commission on tuberculosis, 60 cases of 
the disease in the human being were tested with the result that 14 
were claimed by this commission to have been infected from bovine 
sources. It has been found by Schroeder in this country that even 
when tubercle bacilli are not being excreted by the udder the dirt and 
manure of the stables where the diseased animals are kept are in many 
cases contaminated with tubercle bacilli. This contaminated material 
may readily infect the milk even though it comes frpm a healthy cow. 
In a recent examination at the Bureau of Animal Industry, Experi- 
ment Station, of the manure passed by 12 cows purchased from dairy 
farms in this city and infected with tuberculosis to an extent only 
demonstrable by the tuberculin test, tubercle bacilli were found in 
over 41 per cent of the cases. 
Mohler estimates that probably 25 per cent of all the cows which 
supply milk to the District of Columbia are tuberculosis. He fur- 
ther points out the great practical value of the tuberculin test and in- 
sists that all milk should come from either tuberculin tested cattle or 
be subjected to pasteurization under the supervision of the Health 
Department in case the herd is not tuberculin tested. 
