GENUS BACTERIUM 



235- 



usually they are single or in short chains. Involution forms 

 that are short and contain vacuoles are found in old cultures. 

 Staining. It stains with alkaline methylene blue some- 

 what irregularly. Granular, deeply stained areas, alternating" 

 with faintly stained or entirely unstained portions, often ap- 

 pear. This is -quite characteristic and of some value in making 

 a diagnosis in a microscopic examination of smears from 

 .glandered lesions. The irregular staining may be due to a. 



Fig. 53. Bacterium mallei in tissues (Ewing). 



degeneration of the body content, a preparatory stage for 

 sporulation, or a condition of the normal protoplasmic com- 

 position of the organism. It stains quite evenly with carbol 

 fuchsin. It does not take the Gram stain. 



Cultivation. This organism grows best on acid glycerine 

 agar, titrated to +2.5 to phenolphthalein, potato and acid 

 glycerine bouillon. After it has been under cultivation for a 

 few generations it grows quite readily on nearly all of the 

 ordinary media prepared from meat infusions. Sometimes it 



