22 STORRS AGRICULTURAL EXPERIMENT STATION. 
the columns in the tables. Then by moving the trial slip up 
and down the table it is possible to determine at a glance 
whether it agrees with any of the described species. If it is 
found that the characteristics agree practically with those of 
any species given in these tables, reference to the descriptions 
following will give further details and will make identification 
in most cases a simple matter. The whole comparison takes 
only a very few minutes and is a great saving of time over the 
old method of comparing long detailed descriptions. 
THE CHIBE DATRY SPECIES. 
It is necessary to give here a brief statement concerning the 
bacteria which are to be regarded as the distinctive dairy 
organisms of this region. Although the number of species 
found in dairy products as seen by the following pages is 
large, the number of those which are found with very great 
uniformity in dairy products is small. Indeed, as the result 
of my experiments I have concluded that the dairy organisms 
of this region are chiefly of four species. Strictly speaking, it 
is probably more correct to say three groups of closely related 
bacteria rather than four single species. ‘They are as follows: 
The most abundant of our dairy organisms is No. 206, which 
is the B. acidi lactici (Esten). As already mentioned in a pre- 
vious publication,* it is almost universally found in samples of 
milk or cream. ‘This appears to be true not only of milk and 
cream in this region but of milk from a very wide territory. 
Samples of milk that have been sent us from a large number 
of States have in almost all cases shown the presence of this 
organism in abundance. In sour milk it is almost always 
present. In all samples of ripened cream which we have 
studied it has been found to be by far the most abundant 
species. In most samples of ripened cream this No. 206 forms 
over 75 per cent. of the bacteria present, and sometimes over 
OO; percent: 
The source of this organism in our milk has been a matter 
of some little interest, and has been studied by experiment in 
the last few months. Its almost universal presence in milk, 
together with the markedly anaerobic character, would seem 
to indicate that it probably comes from the milk ducts. This 
* See Report of this Station for 1896. 

