436 



PLAGUE. 



important points. 





They cultivated the same organism from a 



large numberof 

 cases of plague, 

 and reproduced 

 the disease in 

 susceptible ani- 

 mals by inocu- 

 lation of pure 

 ^^^^ ^ ^^^ cultures. It is 



j^:fl|^^^'~V; *":. y iPr^'^^-' , to be noted 

 ^Ktj^U^ftf^ •' * P ' • "'V ^\-* ' *k. f^^^ during an 



l*.-/'/*!-^'.^* r-V-.* /^t^^.'JSji' plague, some- 



times even pre- 

 ceding it, a high 

 mortality has 

 been observed 

 among certain 

 animals, espe- 

 cially rats and 

 mice, and that 

 from the bodies 

 of these ani- 

 mals found dead in the plague-stricken district, the same bacillus 

 was obtained by Kitasato and . ..-- _ 



also by Yersin. ,. • , ^ I 



Bacillus of Plague.— j1/zr;v7- . •'^' t- "'' !'/ l 

 scopical Characters. — As seen ^- '■'","A!* ^ \'l 

 in the affected glands or buboes 

 in this disease, the bacilli ^ r 

 are small oval rods, somewhat ■» *' 

 shorter than the typhoid bacil- . 

 lus, and about the same ' ' ' "- ' ~ ' ' , 



thickness (Fig. 148), though --,. ^ | - -v t\ 



considerable variations in size ^ .~ '?,—"' ^ 



occur. They have rounded •'''s"!~ _ .' ^' 



ends, and in stained prepara- fig. 148, — Bacillus of plague from a 

 tions a portion in the middle of y°""g ™"^''"= °" ^s'^''- 



. . Stained with weak carbol-fuchsin. X looo. 



the bacillus is often left uncov- 

 ered, giving the so-called "polar staining." In films from the 



Fig. 147. — Film preparation Irom a plague bubo showing 

 enormous numbers of bacilli, most of .which show well-marked bi- 

 polar staining. 



Stained with weak gentian-violet. X looo. 



'i> 



r'--i .. \ 



■^ 



i' 



