FORM AND STRUCTURE OP BACTERIA 



33 



are merely appendages of the cell wall and not organs of loco- 

 motion. It may be here stated that flagella have never been 

 demonstrated on bacteria devoid of motility and are always 



FIG. 25. B. typhosus. Showing peritrichous flagellation. After Schmidt 



and Weis. 



found on motile bacteria. The protoplasm of the flagel- 

 lum may be slightly different chemically from the rest of the 

 bacterial cell, for it is a familiar fact that the flagella are very 

 much more liable to heat, chemicals, etc., than the protoplasm of 

 the cell itself. It is possible that the flagella are connected with 

 the cell through pores which connect the internal structures of 

 the two. Under unfavorable conditions the flagella are thrown 

 off, are disintegrated, and completely disappear in a short time. 



