Report’ OF DEPARTMENT OF BACTERIOLOGY. 57 
4. The immersion of the teat cups and the rubber parts of 
the milking machine in a to per ct. solution of salt (NaCl) 
between milkings is important. This treatment reduced the 
average germ content of the milk from over 180,000 germs 
per cc. to less than 20,000 per cc. 
5. The air filters were also important in proportion as they 
removed the germ-laden dust from the air which enters the 
pail during the milking process. On the later types of Burrell- 
Lawrence-Kennedy machines these filters were large enough 
to be quite efficient and the germ content of the milk, when the 
tubes had been held in brine and the filter cups had been prop- 
erly filled with cotton, was almost always markedly below 
10,000 per Cc. 
6. Dropping the teat cups on the floor during the milking 
process or any gross carelessness in handling the machine 
caused a surprising rise in the germ content of the milk. Oc- 
casionally very high counts were obtained when no definite 
cause could be found. Additional study is necessary before all 
of the important factors which influence the germ content of 
machine-drawn milk are understood. 
7. These results do not demonstrate that the milking ma- 
chine is a success because they cover only one of a number of 
important points in connection with the ust of such machines. 
They do indicate that when machines of the better type are 
run properly they will deliver milk with a very low germ 
content. | 
8. At present the greatest difficulty in connection with the 
milking machine is to obtain the kind of man who will so 
operate the present machine as to obtain its maximum of 
efficiency and cleanliness. ‘ 
