TYPES OF BACTERIA FOUND IN MILK 167 
used for drinking or cooking purposes, although there seems to be 
no reason for believing that is it not perfectly wholesome. In 
some countries, indeed, such slimy milk is a favorite beverage; but 
in this country most people, not wishing to drink slime, will throw 
it away. Sometimes such an infection proves very troublesome. 
It may spread through a whole farming district, affecting many 
dairies and continuing for a long time. Although not always easy 
to follow, such infections may generally be traced to some com- 
mon source of distribution. For example, a central creamery, 
receiving such slimy milk from some patron, may 
distribute the trouble over the whole patronizing 
district by returning to the farmers the milk greed 
vessels not properly sterilized. 4 rs 
The cause of this sliminess is the growth of Gest 
bacteria. Several different kinds of bacteria have o one 
been discovered with this property. The best me 3—B 
known of them, and probably the most common, tachs mscosus, the 
is one that has been named B. lactis vtscosus sumy mulk(War D. 
(Fig. 35). This has been found to be the cause 
of the trouble in Europe, and a similar if not the identical 
organism has been found in America. It appears to be a 
very vigorous organism, and, when once present, will grow so 
rapidly as to make the milk slimy in spite of the action of the or- 
dinary acid-forming bacteria that may be present. 
To understand the sources from which this troublesome organ- 
ism is derived may be a matter of great importance to a dairyman. 
Three sources have thus far been detected: (1) Sometimes it may 
come from water used in washing the milk cans or, more likely, 
from the water in which the cans have been standing to cool the 
milk. (2) It may come from the udder of the cow; perhaps a 
single cow in a herd being thus infected and her milk contaminating 
that of the whole dairy. (3) Slimy milk bacteria have been found 
in the dust of the air in dairies. If, therefore, a dairy is troubled 
with slimy milk, the dairyman should look first to his water-supply, 
