ture under study. Other types of small polar monotrichous bacteria 

 may also be found in the distilled water and consequently on the 

 flagella slides. If confusion is likely, the water used for washing 

 the bacteria must be freshly distilled or freshly boiled. In the 

 author's experience the Caulobacter in distilled water usually have 

 no flagella but do have a long stalk which makes them readily 

 recognized. If a washed suspension of bacteria is allowed to stand 

 for several days at room temperature a goodly number of caulo- 

 bacter is usually found in the suspension, where they may or may 

 not be attached by stalks to the washed bacteria (see Figs. 57 and 

 58). 



Flagellar Characteristics 



C. vibrioides in the free living state is a small rod which may 

 be straight, or curved Bke a vibrio. The flagellation is polar mono- 

 trichous. The flagellar wavelength is very short, averaging 0.95 

 micron with an amplitude averaging 0.4 micron. 



In all the cultures studied, for causes unknown at present, the 

 individual bacteria soon begin to grow stalks. The stalk develops 

 on the flagellated end of the organism and the flagellum persists 

 for a limited time on the end of the stalk, even when the stalk is 

 attached to some particulate matter, such as other bacteria. When 

 the stalked bacteria start to divide a new flagellum develops from 

 the end distal to the stalk. Many individuals may become attached 

 to a single particle of matter or to each other with the formation 

 of small and large rosettes. New flagella develop on the distal 

 ends of the daughter cells and the rosettes are soon bristling with 

 flagella. 



Fig. 58. o. This picture is from a distilled water suspension of Bacillus 

 megaterium and caulobacter. The caulobacter is attached by a long stalk 

 to the upper right end of the bacillus. Note the short caulobacter flagellum 

 at the base of the stalk. 



p. An involution form of caulobacter with two polar flagella and appar- 

 ently attached to a Listeria organism with straight flagella. This is from a 

 mixed culture of the two organisms. Multiple polar flagella on caulobacter 

 were very rare. 



q. Caulobacter attached to staphylococci and to each other. From the 

 masses of staphylococci and caulobacter emerge long filaments of caulobacter. 

 Note two flagella on the filament at the right. This picture is from a mixed 

 culture of caulobacter and staphylococci. 



142 



