BACILLUS MALLEI (GLANDERS) 47 



in pairs and occasionally, though rarely, in longer 

 chains. It differs from the tubercle bacillus in the 

 readiness with which it parts with its stain ; all 

 attempts at differentiation, and even the use of 

 alcohol in dehydration robbing the bacillus of its 

 colour. It is not stained by Gram's method. As in 

 the tubercle bacillus, the protoplasm is segregated 

 and the organism beaded, but very frequently, in 

 the shorter forms at least, this segregation leads to 

 polar staining, the bacillus presenting a clear un- 

 stained space in the middle while the two extremities 

 are deeply coloured. Examples of " beading " and 

 " polar" staining may be seen in the photograph. 



Cultures from such purulent material can be 

 obtained on agar (or, better, on glycerine agar),. 

 bouillon, blood serum, and potato at 37° C. 



On agar it forms a rather thick and decidedly 

 glutinous layer ; in bouillon a general, rather slight 

 turbidity, and on potato a thick, brown, viscid, 

 honey-like growth, which is highly characteristic. 

 Preparations from such cultures (Fig. 41) show 

 bacilli of very varying length, ranging from coccoid 

 forms to fairly long filaments. The cultures are 

 very polymorphic and prone to the production of 

 involution forms. The beading and polar staining 

 occur in the cultures. The bacilli from cultures do 



