20 Bacterial Disease of the Mango 



the rods contained small bodies which stained red by Moller's spore 

 stain. 



In the sediment of old broth cultures, the rods stain very unevenly, 

 and are apparently vacuolated. Numbers of them have a large central 

 vacuole with a deeply staining portion at each end. In others, there 

 are several bands of colour across the organism in addition to those at 

 the poles. 



Capsules. 



It has already been mentioned that a delicate capsule could be 

 detected round rods growing on beef broth agar. This was still more 

 evident with dark ground illumination. 



In the ring formed round the tube at the surface of liquid broth 

 (1 x 15 F.) cultures, there are numerous organisms with a very definite 

 capsule (Plate XIV, fig. d). 



When stained by MacConkey's method, these capsuled bacilli take 

 the stain much more deeply than the others; the capsule is unstained 

 and shows as a colourless ring surrounded by the slimy mass in which it 

 is embedded ; the latter takes the stain and appears granular. 



Spores 



I 

 spores but none were detected 



Cultures of various ages and on numerous media were examined for 



Motility. 



In young cultures on agar and in liquid media, the organism is 

 actively motile. The bacteria move rapidly with a forward screw-like 

 movement which does not continue long in the same direction. The rod 

 after proceeding for some distance turns and darts in a different direction, 

 or its progress is interrupted by tumbling movements or by rotation on 

 its long axis. The motile rods are usually single, but fairly frequently 

 pairs may be seen in motion, or occasionally short chains. These move 

 forward in a sinuous manner. 



That flagella are present may be seen by using the paraboloid con- 

 denser with a Zeiss apochromatic objective 3 mm. -95 ap. The number 

 and position of the flagella cannot be ascertained, however, as they are 

 in rapid motion, although it is evident that there are several and thai 

 they are peritrichous. 



When observed under a cover glass, after a while the majority of 

 the rods make their way to the edge of the preparation or to an air 



