64 Bacterial Blujht of Pear Bloasoms in SontJi Africa 



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Fig. 3. Section through diseased receptacle, natural infection, drawn with Edinger's 

 projection apparatus, the scale is indicated. A more advanced infection showing the 

 collapsed tissues. 



Morphology. 



The organism is a short rod of very variable size and shape. A 

 pure culture may be readily obtained from infected tissues, but the 

 milky white masses of bacteria which diffuse out from such tissues 

 consist of rods which exhibit astonishing variations in size and form 

 (Fig. (')). The majority are short thick rods with rounded ends, measur- 

 ing for the most part -6 — 1-5 x -5 — 7 /a, but all the variations found on 

 various culture media may be seen. In addition to these there are 

 undivided rods up to 12 jx long, which are sometimes irregular in shape 

 but which stain intensely with carbol fuchsin ; it would seem probable 

 that these are involution forms of some sort, although nothing resembling 

 them has been found in artificial culture media. The same remark 

 applies to fairly numerous rods of various lengths which stain faintly 

 and are only about •2/x in diameter. All the rods are distinctly capsuled, 

 and many of them are not stained evenly, showing 1 — 2 or, in the larger 

 individuals, as many as 5 — 6 colourless vacuoles. 



