3% sodium chloride, the others in ordinary media made with soya 

 peptone. Unfortunately a culture of Spirillum minus was not ob- 

 tained. 



Flagellar Characteristics 



All spirilla are polar flagellated, usually polar multitrichous or 

 lophotrichous. Only one named species showed polar mono- 

 trichous flagella, namely Spirillum polijmorphum. A polar mono- 

 trichous type was also observed in a smear from the dog intestine 

 and is illustrated in Fig. 26k. The typical flagella of spirilla have 

 a very long wavelength (over 3 microns) and usually less than 

 one complete wave. Only one culture, Spirillum linum, showed 

 an occasional flagellum with short wavelength (about 1.5 microns) 

 and several waves (Fig. 26m). This flagellum may be con- 

 sidered as the curly variant although the wavelength is consider- 

 ably greater than the curly flagella of most bacteria. In the marine 

 forms the oval "microcysts" were much in evidence. These showed 

 the same flagellation as the normal organisms, as illustrated in 

 Figs. 26h, i, j. Although it is usual to find flagella at both ends of 

 a spirillum, organisms with flagella at only one end were present 

 in every culture. In spite of all the statements in the literature 

 about the unusual nature of the flagella on spirilla the author 

 finds them no different fundamentally from the flagella of other 

 bacteria. The genus Lophomotms has the same type of flagellation 

 as Spirillum, as have also a few Pseudomonas types, particularly 

 among the plant pathogens. Most bacteria, however, have flagella 

 with more curves. 



2 5. Azotobacter 



Complete agreement on the taxonomy of Azotobacter appar- 

 ently has not been reached. Bergey's Manual lists three species 

 and does not include Azotobacter vinelandii. Azotobacter macro- 

 cytogenes is also not included. Eight strains labeled Azotobacter 

 chroococcum were received; one from William D. Haynes of the 

 Northern Regional Research Laboratory of the U.S.D.A., Peoria, 

 Illinois, and seven strains from Perry Wilson of the University of 

 Wisconsin. Four of the Wilson strains showed good motility and 

 were typical in every respect including a light brownish pigmenta- 

 tion. The other strains were nonmotile or so poorlv motile as to 



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