MORPHOLOGY 



a bacterium and their mode of attachment as a basis for distin- 

 guishing and separating various genera. Fischer, in 1895, 

 used the flagella as means of distinguishing subfamilies. 



The flagella are long 

 delicate processes, usu- 

 ally one to twenty 

 times longer than the 

 bacterial cell (i to 

 20 X). They possess 

 a base which is slightly 

 larger than the rest of 

 the process. This base 

 tapers like a cone, with 

 a long filamentous pro- 



FIG. 24. Spirillum rubrurn. Showing ampho- CCSS Coming off the 

 trichous flagellation. After Schmidt and Weis. 



apex. The mode of 



attachment of the flagellum to the bacterial cell is not as yet 

 definitely settled. It is probable that the protoplasm of the 

 bacterial cell is continued out into the flagella and that there 

 is a thin limiting membrane on the outside, similar to, al- 

 though much thinner than, the cell wall proper. By the use of 

 :ertain reagents the protoplasm of the flagella has been seen to 

 shrink away from the limiting membrane, and an attachment 

 has been noted of the flagellum to the peripherial zone of 

 protoplasm of the cell. Some writers hold that the flagellum 

 is definitely separated from the cell wall and composed of 

 different material. Some have also held that the flagella 



