GENERAL SYSTEMATIC BACTERIOLOGY 21 



I. Filaments short, cylindric or filiform..!. Vibrio 

 II. Filaments filiform, articulated, spirally twisted. 



2. Spirillum 

 III. Filament spiral, much elongated 3. Spirochaeta 



B. Filaments colored (often only pale blue) sheathed, usually not moving, rarely 



slowly oscillating Subfamily II. Leptothricheae. 



One genus of the two included, Leptothrix, is often classed with the bacteria. 



C. Filaments more or less colored, sheathed, often showing active oscillation. 



Subfamily III. Oscillarieae 

 One genus, Beggiatoa is now generally classed with the bacteria. 



As a footnote under the heading '' Fungorum genera Leptothricheis 

 et O'scillarns quasi affinia:" the following genera are included: Cryp- 

 tococcus, Ulvina, Sphaerotilus and Hygrocrocis. 



In the genus Vibrio the following species are listed, V. lineola,V. 

 tremulans, V. subtilis, V. rugula, V. purolifer, V. serpens, and V. bacil- 

 lus. In the genus Spirillum are included Sp. undula, Sp. tenue, Sp. 

 volutans and Sp. rufum. The single species of Spirochaeta is Sp. 

 plicatilis. 



Hallier (1866) introduced the theory of pleomorphism as applied to 

 microorganisms. As a result of his work no additional knowledge of 

 bacterial classification was developed, indeed it was probably somewhat 

 instrumental in retarding advance. No generic names are to be ascribed 

 to him, although he introduced certain names to designate what he 

 believed to be growth forms, and which were later used by various au- 

 thors as genera. 



Davaine (1868) concluded as a result of his study of the anthrax or- 

 ganism that this microbe was closely related to the other bacteria, but 

 unlike those previously described, non-motile. To this type he gave the 

 generic name Bacteridium. A key to the genera of bacteria which he 

 recognized is as follows: 



Davaine's Classification of Bacteria (1868) 



a. Filaments straight or bent, never spiral, 

 b. Motile. 



c. Cells rigid Bacterium 



CO. Cells flexuous, sinuous Vibrio 



bb. Non-motile Bacteridium 



aa. Filaments spiral Spirillum 



Cohn (1870, p. 108) described one of the filamentous iron bacteria 

 as Crenothrix poly-spora. Klebs (1871) in conformity with his ideas on 

 bacterial pleomorphism gave the name Microsporon septicum to the 

 pleomorphic organism which he associated with pus infections. 



