32 MICROBIOLOGY 



2. BACTERIA'CEAE. 



Cells without organs of motion 1. Bacterium. 



Cells with organs of motion (flagella). 



a. Flagella distributed over the whole body 2. Bacillus. 



b. Flagella polar 3. Pseudomonas. 



3. SPIRILLACEAE. 

 Cells rigid, not snake-like or flexuous. 



a. Cells without organs of motion 1. Spirosoma. 



b. Cells with organs of motion (flagella). 



1. Cells with 1, very rarely 2 to 3, polar fla- 

 gella 2. Microspira. 



2. Cells with polar flagella tufts 3. Spirillum. 

 Cells flexuous 4. Spirochaeta/ 



4. CHLAMYDOBACTERIACEAE (higher bacteria). 

 Cell contents without granules of sulphur. 



a. Cell threads unbranched. 



I. Cell division always in one plane 1. Streptothrix. 



II. Cell division in three planes previous to the 

 formation of gonidia. 



1. Cells surrounded by a very delicate, scarcely 

 visible sheath (marine) 2. Phragmidiothrix. 



2. Sheath clearly visible (in fresh wa- 

 ter) 3. Crenothrix.. 



b. Cell threads branched 4. Cladothrix. 

 Cell contents containing sulphur granules 5. Thiothrix. 



5. BEGGIATOACEAE. 



Thread like bacteria without a sheath, motility due to an 

 undulating movement. Sulphur granules are not present. 



Fischer- in a series of studies on the introduction of 

 general bacteriology, has proposed a classification in which 

 he has introduced a number of sub-families and new genera. 



* Fischer. Vorlesimgen iiber Bakterien, Leipsig (1897) trans- 

 lated by A. C. Jones, The Structure and Functions of Bacteria, Ox- 

 ford, 1900, p. 32. 



