306 BACTERIAL DISEASES OF PLANTS 



polar flagellate (Fig. 237), non-sporiferous, Gram negative, non- 

 acid-fast, liquefying (gelatin, not Loffler's blood serum), milk- 

 clearing (by a lab ferment with formation of tyrosin), non-gas- 

 forming and aerobic (in fermentation tubes in peptone water 

 with dextrose, saccharose, lactose, maltose, glycerin ormannit), 

 non-nitrate-reducing, green fluorescent (a pale yellowish-green 

 stain in milk, peptone beef bouillon, peptone beef agar, peptone 

 beef gelatin, Fermi's solution and Uschinsky's solution), alkali- 

 tolerant (NaOH down to -25 in beef bouillon), acid tolerant (in 

 bouillon up to +34 for oxalic acid, and +36 for malic acid and 

 citric acid), sodium chlorid-sensitive (beyond 2 per cent at 

 4 per cent in bouillon motility ceases, and at 5 per cent there 

 is scarcely any growth); chloroform-tolerant; grows below 0C. 

 but is injured by freezing in bouillon (70 to 90 per cent killed) l , 

 dry-air sensitive (very), sunlight-sensitive (very), heat-sensitive 

 (very), short rod-shaped, catenulate (on agar and in 4 per cent. 

 NaCl bouillon) or filamentous schizomycete (0.8 to 0.9^ in 

 diameter), growing on +15 peptone beef agar plates in form of 

 round, smooth, flat, shining, translucent, opalescent, white, 

 entire-margined colonies, becoming 1 to 3 mm. in diameter in 

 3 or 4 days at 23C., at which time or earlier the inner structure 

 is coarsely granular and reticulate under the hand-lens. Later 

 the inner structure becomes finely granular and the reticulations 

 disappear. In thin-sown plates at the end of 7 days the surface 

 colonies are 6 to 8 mm. in diameter, and after 15 days 12 to 

 15 mm. in diameter. With age the colonies become dull or dirty 

 white, and slightly irregular in shape, with undulate or faintly 

 crinkled margins into which run indistinct radiating lines. The 

 buried colonies are small and lens-shaped. 



On +10 nutrient beef-peptone gelatin plates, after 3 days 

 at 17 to 18C., the well-isolated colonies vary from mere points 

 to round growths 2 mm. in diameter. The gelatin is liquefied 



1 The statement on p. 13 of Bull. No. 225, Bureau of Plant Industry, is erroneous. 



FIG. 235. One of a number of spotted and blotched New York cauliflower 

 leaves received from Prof. H. H. Whetzel in the fall of 1918. The leaves were 

 yellowish and the spots pale green to black. These gave an organism culturally 

 the same as Bacterium maculicolum McC., and this produced the characteristic 

 lesions when sprayed upon cauliflowers in one of our houses, and from one of these 

 Fig. 236 was obtained. Good infections were also obtained with it in Feb., 1920. 



