CLASSIFICATION OF DAIRY BACTERIA, | 13 
CLASSIFICATION OF DAIRY BACTERIA. 
BY LS ANY we ONIN & 

COLLECTION OF THE BACTERIA. 
For the last ten years, in which the work upon dairy bacte- 
riology has been carried on for this Station, I have been 
gradually collecting from the dairy products of the vicinity a 
variety of forms of bacteria. These have been obtained from 
milk and cream and occasionally from butter. During that 
time a very large number of different cultures have been iso- 
lated from these dairy products, and have been studied in the 
laboratory by bacteriological methods with more or less com- 
pleteness. Of the many hundreds thus collected, large numbers 
of course have proved to be duplicates. As fast, however, as it 
became apparent that any particular form isolated and studied 
was distinct from those previously characterized, the bacterio- 
logical characteristics of the new variety were carefully detailed 
and the form was entered in a list by number, together with 
the characteristics as they were determined. In this way there 
has accumulated a list of over 200 different types of bacteria 
which have been regarded as more or less distinct from each 
other. It may be assumed that this list contains probably all 
‘of the common species of bacteria which are likely to be found 
in dairies of this vicinity. Of this long list many of course 
have been found to be very commonly, some indeed almost 
-universally, present in milk. Others are more uncommon, 
being found only a few times, and many indeed have been 
isolated only a single time and must therefore be regarded as 
purely accidental. It has been found, as would be expected, 
that the species of bacteria in a sample of milk vary somewhat 
with the locality from which the milk is obtained, and also 
with the season of the year in which the examination 1s made. 
A few forms of organisms are so widely distributed as to be 
almost universal, both as to locality and as to season. 
Of the bacteria in my list there are quite a number that have 
not been described with sufficient accuracy to make the descrip- 
tion of any considerable value. This is true especially of some 
