34 Walter H. Burkholder 



It was found that certain strains seemed to vary from the original, and 

 these variations are pointed out. Phytomonas Jlaccumfaciens appears not 

 to be as stable a species as Phyt. phaseoli. 



Morphology 



Phyt. Jlaccumfaciens is a short rod with rounded ends, non-spore-forming, 

 occurring singly or in pairs. The longest rods often show a slight curve, 

 and a few of the cells appear to be larger at one end than at the other. 

 Grown on beef-extract agar (pH 6.9) at a temperature of 27° C, the cells 

 of a culture twenty-four hours old measured: 1.75/* (0.9 to 2.7ju) by 0.82/x 

 (0.6 to 1.2ju). Granules have been observed in the cells. 



The organism is motile by means of a single polar flagellum. It is not 

 acid-fast, but is Gram-positive. One strain proved to be Gram- variable, 

 and even grew well in gentian-violet agar. Capsules have not been 

 observed. 



Cultural characteristics 

 (All cultures incubated at 27° C. unless otherwise stated) 



Beef-extract agar slants (pH 7.0). Growth appears in twenty-four hours. 

 The growth is never more than moderate, is filiform, smooth, translucent, 

 and straw yellow in color. The color appears to vary with the lot of 

 media. In some cases there is scarcely any pigment production until 

 after three or four days, and then it may be very weak. In other cases 

 the pigment may be deep and similar to that of Phyt. phaseoli. The 

 consistency is often viscid. 



Beef-infusion agar slants (pH 7.0). Growth is similar to that on beef- 

 extract agar, although sometimes it is more copious. The color is more 

 intense on this agar, and becomes in several days a light cadmium. 



Beef-extract agar plates (pH 7.0). Seven-days-old colonies are circular, 

 approximately 3 to 5 millimeters in diameter, and mustard yellow in 

 color. The consistency is slightly stringy. 



Beef-extract bouillon (pH 7.0). The medium becomes slightly cloudy within 

 twenty-four hours. Growth advances somewhat, but there is never 

 more than a moderate cloudy appearance. A light sediment is formed. 



Gelatin stab (pH 6.6). (Temperature 21° C.) Growth appears along the 

 stab within twenty-four hours. Liquefaction varies with the strain, and 

 may begin within three days to three weeks. In some cases liquefac- 

 tion has been complete in five weeks. In certain lots of gelatin, several 

 strains have shown no liquefaction at all. 



Litmus milk. Litmus milk begins to turn pink on the fourth day. A 

 distinct yellow ring is formed, and after a week's time reduction of the 

 litmus commences. After four weeks a soft curd is formed, which 

 becomes solid, and in some cases a slight peptonization takes place. 

 Many variations of this procedure may occur: in litmus reduction, from 



