NOMENCLATURE AND CLASSIFICATIONS. 



157 



of bacteriology, not now in use, and most of which can not be attached with certainty 

 to any specific organism, or to any definite group of organisms? 



From time to time, as new discoveries have been made, our views as to what 

 should be considered generic characters have undergone decided modifications, as 

 everyone knows who is familiar with the various writings on systematic bacteri- 

 ology, especially those which have been the most widely read and have exerted the 

 most influence. A full discussion of all the various problems of generic nomencla- 

 ture is not, however, contemplated in this connection. It is safe to predict that no 

 system now extant can be looked upon as a finality, since we know as yet too little 

 about these numerous and variable organisms to devise an altogether consistent 

 system. Classifications are conveniences, nothing more. Some conform more 

 nearly than others to the observed facts, but none are perfect or, from the nature of 

 the case, can ever be final. What the future may have in store no one can tell. 

 There will undoubtedly be many surprising discoveries, and recent attempts at 

 classification may then appear very crude. Our concern, however, is chiefly with 

 the present and with knowledge as it appears to-day. 



On the whole, the classification of Migula, which was proposed in October, 1894, 

 and is outlined at length and applied to most of the well-recognized forms, in his 

 beautiful great work, " System der Bakterien," appeals to me most strongly. Up 

 to this time the writer has followed this system in his own publications and will 

 continue to do so, with certain modifications, until some distinctly better system 

 makes its appearance. This system is based on the flagella and is much more 

 workable than one based on spores, or on a combination of these two characters. 

 The presence or absence of flagella and their position on the body are used by 

 Migula as generic characters. 



In 1895 Dr. Alfred Fischer also propounded a new system of classification 

 based on spores and flagella. This system was repnblished in 1897, with material 

 modifications, in his " Vorlesungen iiber Bakterien," and is modified still further in 

 the second edition of that work. In the non-twisted, rod-shaped bacteria use is 

 made of the flagella to separate the subfamilies, while the generic characters are 

 derived from certain phenomena incident to spore-formation. The following table 

 of 17 genera, taken from his first paper, shows this system at a glance: 



FISCHER'S TABEU.ARISCHE UEBERSICHT DER BACILLACEEN. 



