12 BACTERIA 



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of voluntary motion, they are seen to oscillate, tremble or move 

 slightly. Suspensions of india-ink in water are seen to do the 

 same thing, as are other inanimate suspensions. This molecular 

 movement is known as the Brownian motion. By ordinary 

 staining methods, and in preparations of living bacteria known 

 to be flagellated, these organs of locomotion cannot be seen, 

 as a rule. Occasionally, however, one may be seen under either 

 condition. Generally, strong solutions of aniline dyes, to which 

 powerful mordants have been added, are necessary to stain the 

 capsule of bacteria and the attached flagella. The motion of 

 bacteria varies from a simple rotatory, on one axis, to a swing- 

 ing, shaking, boring or serpentine action. The location of the 

 flagella has some influence upon the motion they impart. 

 Flagella may be broken off from the cell body by agitation, 

 but when separated may still be clumped by agglutinating sera. 



Flagella may have other functions than locomotion. It is 

 possible that they serve as organs for the absorption of nour- 

 ishment from the surrounding media. The presence of very long 

 or very numerous flagella does not necessarily presage very 

 active motion. At times, under certain conditions, an organism 

 ordinarily motile and flagellated will appear immobile and non- 

 flagellated (Lehmann and Ziferler), but this is rare. Certain 

 flagella have in their continuity little round granules, or bodies, 

 which apparently have nothing to do with the functions of 

 locomotion but may have something to do with the nutrition 

 of the cell. The test of motility of a bacterium is to see it pro- 

 gress by itself completely across the field of the microscope. 



REPRODUCTION. The process of direct cell division is 

 the commonest way by which bacteria multiply; hence comes 

 the name of fission fungi. The ways of reproduction of the 

 bacteria high in the scale are by direct division, branching, and 

 by means of spores, and by other granules called gonidia. The 

 spores appearing in the lower bacteria, bacilli for example, are 

 not reproduction forms but states of high resistance. 



