CLASSIFICATION OF THE BACTERIA. 87 



related to them, — the Leptothrix, Beggiatoa, and 

 Crenothrix. 



1. Fil. with indistinct articulations 



Fil. very slender, short .... Bacillus. 



Fil. very slender, long .... Leptothrix. 



Fil. thick, broad Beggiatoa. 



2. Fil. articulated distinctly .... Crenothrix. 



g. Bacillus, Cohn. 



The bacilli are characterized by slender fila- 

 ments, straight, short or of moderate length, 

 rigid or flexible, endowed or not with motion. 



One species is chromogene, the B. ruber of 

 Cohn. Finally it is to this genus that we should 

 refer the Amylobacter of Trecul. 



B. subtilis, Cohn {Vibrio subtilis, Ehrb.; Ferment 

 butyrique, Pasteur). 



Filaments very slender and elongated, formed of a 

 single cell having usually a length of 6 /x, or of two 

 articles of which the total length is then' 12 fi, or of 

 three (length 16 /a), or of a greater number (some- 

 times as many as twenty, with a total length of 40 to 

 60 and 130 /x) ; thickness not measurable, well-defined 

 movements of flexion, active or passive, and of trans- 

 lation forward or backward ; reproduction by fission 

 and by globular or oval spores developing themselves 

 in the interior of the articles (Cohn). Is found in 

 stagnant water. 



Plays a great role in the butyric fermentation 

 (Pasteur). This B. exists in rennet, can support 

 a temperature of 105°, and live in a medium 

 deprived of free oxygen, in which case it takes 

 a form cephalee, containing persistent spores, 



