412 



PLAGUE. 



middle of the bacilli, giving the so-called " pole-staining." 

 In the tissues they are found scattered amongst the cells, 



for the most part lying 

 singly, though pairs 

 are also seen ; but in 

 cultures, especially in 

 fluids, they have a 

 tendency to grow into 

 chains, the form 

 known as a strepto- 

 bacillus resulting 

 (Fig. 100). Some- 

 times in the tissues 

 they are seen to be 

 surrounded by an 

 unstained capsule, 

 though this appear- 



FIG. ioo. Bacillus of plague in chains ance is by no means 

 Fr m a youns invariable. They do 



not form spores, and 



they are non-motile. 



They stain readily with the basic aniline stains, but are 

 decolorised by Gram's method. 



Distribution in the Body. The bacilli have a special 

 relation to the anatomical changes in the tissues. The 

 most striking feature in the disease is the affection of 

 the lymphatic glands, which undergo intense inflammatory 

 swelling, generally ending in a greater or less degree of 

 suppuration if the patient lives long enough. Usually one 

 group of glands is affected first in the great majority the 

 inguinal or the axillary glands and afterwards other groups 

 become involved. Along with these changes there is great 

 swelling of the spleen, and often intense cloudy swelling of 

 the cells of kidneys, liver, and other organs. The bacilli 

 occur in enormous numbers in the swollen glands, being so 

 numerous that a film preparation made from a scraping 

 almost resembles a pure culture; they lie irregularly arranged 

 between the cellular elements. In the spleen also they are 



Stained with thionin-blue. x 1000. 



