PLAGUE AND BACILLUS PESTIS 827 



bacilli, first classified together by Hueppe 34 in 1886. Some confusion 

 has existed as to the forms which should be considered within 

 Hueppe 's group of "hemorrhagic septicemia," a number of bac- 

 teriologists including in this class bacilli such as Loeffler's Bacillus 

 typhi murium, and Salmon and Smith's hog-cholera bacillus, micro- 

 organisms which, because of their motility and cultural character- 

 istics, belong more properly to the "Gartner," "enteritidis," or 

 "paratyphoid" group, intermediate between colon and typhoid. 



The organisms properly belonging to this group are short bacilli, 

 more plump than are those of the colon type, showing a marked 

 tendency to stain more deeply at the poles than at the center. They 

 are non-motile, possess no flagella, and do not form spores. They 

 grow readily upon simple media, but show a very marked preference 

 for oxygen, growing but slightly below the surface of media. By 

 some observers they are characterized as "obligatory aerobes, " but 

 this is undoubtedly a mistake. 



While showing considerable variations in form and differences 

 in minor cultural characteristics, the species characteristics of polar 

 staining, decolorization by Gram, immobility, lack of gelatin lique- 

 faction, and great pathogenicity for animals, stamp alike all mem- 

 bers of the group. Its chief recognized representatives are the 

 bacillus of chicken cholera, the bacillus of swine-plague (Deutsche 

 Schweineseuche), and the Bacillus pleurosepticus which causes an 

 acute disease in cattle and often in wild game. 



Because of certain cultural and pathogenic characteristics, it 

 seems best to consider the bacillus of bubonic plague with this group. 



BACILLUS OP CHICKEN CHOLERA 



(Bacillus avisepticus) 



The bacillus of chicken cholera was first carefully studied by 

 Pasteur 35 in 1880. It is a short, non-motile bacillus, measuring from 

 0.5 to 1 micron in length. Stained with the ordinary anilin dyes, 

 it displays marked polar staining qualities, which often give it the 

 appearance of being a diplococcus. It is decolorized by Gram's 

 method. It does not form spores, but may occasionally form 

 vaciiolated degeneration forms, not unlike those described for Bacil- 

 lus pestis. 



34 Hueppe, Berl. klin. Woch., 1886. 



35 Pasteur, Comptes rend, cle Pacad. des sci., 1880. 



