BACTERIA OF PLANT DISEASES. 577 



In cultures the dimensions vary still more. In recent cultures the bacilli 

 exhibit active movements, which are soon lost. The bacilli are often asso- 

 ciated in viscous masses, forming- milk-white drops, which when touched 

 with a platinum needle may be drawn out into long threads. This viscosity 

 appears to be due to a swollen and partially liquefied capsule, which may be 

 demonstrated under the microscope in stained or unstained preparations. 

 Does not form spores. Grows in bouillon, Dunham's solution, etc. Does 

 not form a surface film or a deposit at the bottom of the test tube, but the 

 culture medium is slightly clouded. Grows very slowly or not at all in gela- 

 tin and does not liquefy. Upon agar-agar it grows as a thin, smooth, milk- 

 white, sticky layer, which extends only a short distance from the point of 

 inoculation. In stab cultures it grows all along the line of puncture, form- 

 ing, after a time, finger-like projections, which under a lens are seen to be 

 finely granular. Upon potato it forms a thin, smooth, white, moist-looking 

 layer, which only extends a short distance from the line of inoculation. 

 The color of the growth resembles that of the potato, and is much whiter 

 than that of most bacteria. It produces no pigment and causes no change 

 in the color of the potato. In culture solutions containing dextrose, saccha- 

 rose, lactose, or maltose no gas is developed. It does not cause coagulation 

 of milk. It grows best in alkaline media. It is destroyed by a temperature 

 of 43 C. maintained for ten minutes. Cultures in liquid media or on potato 

 usually die out within three weeks. It stains best with carbol-fuchsin solu- 

 tion. In properly stained preparations it is seen to have a capsule and 

 flagella in some bacilli one flagellum at each extremity of the rod, while in 

 others there are more " (Smith). 



37 



