00 Bacterial BJupit of Pear Blossom^^ in Soiff/t Africa 



quite as frequently obliquely, or are attached almost laterally (Fig. 4). 

 One or two vacuoles, the contents of which do not stain with carbol 

 fuchsin, can be seen in many individuals ; that these non-staining 

 areas are not due to plasmolysis is proved by the fact that they can be 

 clearly seen in the living condition with the dark ground illumination, 

 by which means also the capsule is plainly visible. The capsule stains 

 readily with carbol fuchsin or gentian violet, and is very obvious around 

 rods from the condensation water in tubes containing nutrient agar 

 cultures about four days old. The growth in the condensation water 

 is very viscid, in consistency almost like egg albumen ; short rods and 

 almost coccus-like forms predominate. These stain intensively with 

 carbol fuchsin, are surrounded by a colourless capsule and are em- 

 bedded in a slimv matrix w^iich stains faintlv. 



After four weeks at 25° C. on nutrient agar only a small percentage 

 of the rods stain intensely, the staining of the majority being very faint 

 and uneven. 



In broth cultures the prevailing forms are slightly longer than those 

 on agar, rods 2 — 2-5^ long being frequent; the vacuolation is distinct. 



Very characteristic rods are found in Uschinsky's solution (Fig. 5), 

 Capsuled bacteria form a pellicle on the surface of the fluid ; this sinks 

 when disturbed and forms a sediment. The capsule is very con- 

 spicuously developed, and the growth is viscid in character like that 

 described in the condensation water at the base of agar streaks ; each 

 rod has one, two or more distinct vacuoles. 



The organism is actively motile' in young cultures (less so as it 

 diffuses out from the tissues of the host) by means of 1 — 5 polar flagella; 

 these are two to three times the length of the rod, and are occasionally 

 bi-polar but most frequently they are only at one pole. The flagella 

 stain quite readil}^ by Ellis's modification of Loffler's method (Fig. 7). 



Staining reactions. 



Carbol fuchsin is undoubtedly the best stain for this organism, 

 although it stains well with all the usual stains. It does not stain by 

 Gram's method, and is not acid fast. 



Cidtural characters. 



Nutrient agar (+15). Colonies are visible after 24 hours at 25° C. as 

 thin milky-white growths 1 — 3 mm. in diameter and rather irregular in 

 shape; after 48 hours, surface colonies are 1 — 2 cm. diameter, in thinly 

 sown plates, spreading, sub-circular to irregular in shape, the edges 



