I4 STORRS AGRICULTURAL EXPERIMENT STATION. 
of the earlier varieties that were isolated before the methods of 
description were sufficiently worked out; and it is also true of 
some of the later ones which were by accident lost before a 
complete description was obtained. Moreover, during the 
period in which these experiments have been going on the 
methods of bacteriological work and description have been 
quite materially changed, and it is now considered essential 
to determine certain characteristics which in early years were 
not much attended to. The result is that the descriptions 
given beyond of the different bacteria are of varying value. 
No one can be more fully aware of the incompleteness of some 
of these descriptions than myself, and for this reason a consid- 
erable number of the bacteria in the list which I have collected 
will be left out from the following classifications because the 
descriptions are too incomplete to be of any particular value. 
NEED OF CLASSIFICATION OF BACTERIA. 
As the list of dairy bacteria in my hands has thus been 
increased, it has been found more and more necessary that 
some kind of classification and grouping of these different bac- 
teria should be devised. When the number reaches into the 
scores it is a matter of very great difficulty to determine 
whether the new culture isolated from milk is really new or 
is identical with some of the forms previously studied, and it 
becomes therefore absolutely necessary that some simple means 
of grouping the different bacteria should be obtained to make 
this determination possible. During the past few years I have 
gradually developed a method of grouping these bacteria which 
has proved extremely useful in my laboratory and has very 
greatly simplified the problem of the further study of new 
varieties isolated. 
Inasmuch as it has proved so useful in the determination of 
the forms found here, I have thought it not unwise definitely 
to formulate the method of grouping which has been used, and 
to publish along with it the descriptions of all of the more 
important of the varieties of bacteria which have been isolated 
here. There are at the present time a number of American 
bacteriologists working upon dairy bacteriology, and it is emi- | 
nently desirable that they should be able to compare their 
results with each other. As Jong as the species found by one 
bacteriologist are described only in private notes, they cannot 
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