PATHOGENIC BACTERIA 177 



Bacillus of Soft Chancre (Ducrey-Unna, 188g). Adiplo- 

 bacillus which is specific has been described by Ducrey as 

 obtained from the secretion and in the depth and margins of 

 the chancroid. Unna's bacillus is narrower and unbroken in 

 the center. 



Cultivation. Cultivation has occurred on blood-agar, the 

 blood being added in the proportion of one to two. Colonies are 

 small, round globules. 



Staining. With borax, methylene-blua, decolorized with 

 weak acetic acid. 



Pathogenesis. Probably a mixed infection occurs in most 

 chancroids, especially if buboes result. The bacillus of Ducrey 

 is not found in unopened buboes, though often contaminating 

 the ulcerated ones. 



The disease has been reproduced by inoculation of the human 

 subject. Laboratory animals are immune . 



Bacillus of Bubonic Plague (Yersin and Kitasato, 1894). 

 Bubonic plague or pest is an extremely infectious disease, 



* * 



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m$^^3 



t;^c*V>Ew 



f' -\'-' J i' '^ . 



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Fig. no. Bacillus of bubonic plague (Yersin). 



more or less common in China and the East, and is believed to 

 have its origin in man from rats and other rodents. It spreads 

 with great rapidity, especially among those living under unsani- 

 tary conditions. 



