CLASSIFICATION OF DAIRY BACTERIA. 103 
select the salient features, and so far as possible those that 
are the least subject to variation, and so tabulate them as to 
make it feasible and convenient for other students to recognize 
the types in question and to identify them with any other form 
they may be studying. We have, therefore, in the following 
pages placed emphasis wholly upon the question of drief diag- 
nostic characters and in arranging them in such a form that 
they can be easily utilized, rather than in a detailed descrip- 
tion of species. 
We have also learned from experience that unless the char- 
acteristics of species can: be clearly and distinctly tabulated, it 
is almost a hopeless task for anyone to identify a new culture 
with one previously described. The methods of description 
that have been in vogue in the first decade of the study of 
bacteria have been to describe in somewhat verbose detail all 
sorts of minute characteristics, which later discovery has shown 
to be of little or no significance. These have been commonly 
arranged in no order and have never been tabulated. The 
result has been that it is almost impossible to identify any 
previously described type of bacteria. Consequently the bac- 
teriological literature has seen a constant succession of new 
types described, and when these descriptions are compared 
with each other it becomes more and more evident that the, 
same general type of bacterium has been described over and 
over again by different bacteriologists and given name after 
name. Undoubtedly some of our most common dairy organ- 
isms have been given a dozen or fifteen names, due to this un- 
fortunate method of describing species by long details. We 
have endeavored, so far as possible, to correct this error in our 
classification, by excluding all unimportant data and keeping 
only what seemed to be the distinctive and more or less con- 
stant characters, and then to arrange these in such tabular 
form by methods already known so as to make it possible to 
use them conveniently. 
We have arranged our classification as follows: We have 
first inserted a detailed description of the different bacteria which 
we recognize under different names. Instead of attempting 
however, to describe these to any great length, as would be 
necessary if all of the characters were filled out which are de- 
manded by the description blanks of the American Society of 
