PREFACE 11 



and of the more recent work of a committee on classification of bac- 

 teria under the chairmanship of Dr. Bergey. The work of Mrs. Enlows 

 in the names of bacterial genera is also to be commended. It is to be 

 expected that, as a result of their work, eventually a practical sys- 

 tem of nomenclature which will be satisfactory and applicable to all 

 fields of bacteriology will be evolved. 



But, it may be asked, is a scientific classification of bacteria really 

 important and desirable? Are we not making progress in our science 

 quite as rapidly as we would without the increased emphasis upon 

 taxonomy? The following statement by H. Marshall Ward, pub- 

 lished two decades ago is apropos: 



"The only really valid objection to a purely scientific classification 

 is the old objection of the purely utilitarian practical man; and even 

 there the objection is relative. This leads me to bring out the point 

 that the bacteriologists in the widest sense of the word are really 

 looking at the question of classification from at least two very dif- 

 ferent points of view: On the one hand, we have the botanists, who 

 direct their attention to the organism, the Schizomycete itself, as a 

 biological phenomenon to be examined and reported upon as thor- 

 oughly as possible, for them no classification is complete which does 

 not record, or (which amounts to the same thing) imply in its records, 

 all of the life phenomena of the organism, including its pedigree. 



"On the other hand, we have the pathologists, hygienists, brewers, 

 chemists, etc., who regard the organism simply as an object to be named 

 for convenience in reference, because it brings about certain changes 

 in tissues, waters, and other media which they are more especially 

 concerned with. They do not care, and naturally so, what vagaries 

 the organism exhibits, so long as they can recognize it when they 

 meet with it. As a matter of experience, however, it is just these 

 vagaries that bring about the sources of error which beset them on 

 all hands, and hence they are equally interested with the botanist 

 in having them cleared up and explained. When we come to the 

 conclusion that, whatever may be believed to the contrary, the real 

 interests of bacteriologists of all kinds are identical." 



The first chapter of the present volume is devoted to a brief history 

 of the various classifications of bacteria that have been proposed up 

 to the present time. An effort has also been made to give dichotomous 

 keys to the genera and higher groups recognized by the various writers 

 whenever there seemed to be sufficient data for their formulation. 

 Contrary to commonly accepted opinion, it will be found that a large 



