148 DISEASES OF THE SWEET PEA 



appear within 24 to 36 hours. The center 

 becomes granular and the colonies have a 

 marked tendency to become stellate or au- 

 riculate (fig. 29) . 



Morphological studies show the organ- 

 ism to be a comparatively small rod-shaped 

 bacillus, which in fresh cultures is rarely 

 found in chains, and seldom united in twos 

 or fours. The flagella or appendages of 

 the organism are not easily demonstrated; 

 they are shed so readily that usually not 

 more than two to five may be found in 

 stained material and these are generally 

 quite short. However, when the proper 

 material is selected, carefully fixed and 

 stained, the flagella may be demonstrated 

 to be very long and delicate, and to be 

 from 8 to 12 in number and well dis- 

 tributed peritrichially. 



