PATHOGENIC BACTERIA 139 



Points of Resemblance between Bacillus Typhi and Bacillus 

 Coli Communis. One, microscopic appearance; two, agar and 

 gelatin cultures; three, sometimes growth on potato the same; 

 four, staining peculiarities; five, resistance to phenol. 



Points of Difference: 



Colon Bacillus. Typhoid Bacillus. 



Less motile. Actively motile. 



Gelatin colonies develop more Develop more slowly. 



rapidly. 



Produces gas on dextrose or Does not. 



lactose media. 



Coagulates milk. Does not. 



Produces indol. Does not. 



Growth on potato visible. Invisible. 



Changes neutral red to yellow. Does not reduce neutral red. 



Differences are also noted in the growth on special media, 

 such as those of Hiss and Eisner. 



Varieties. By some bacteriologists the following bacilli are 

 all considered forms of the colon bacillus. Bacillus lactis 

 aerogenes of Escherich; B. cavicida, of Brieger; B. neapoli- 

 tanus of Emmerich; B. enteritidis of Gartner, and, together 

 with some other allied organisms, they are spoken of as the 

 " colon group." 



Saccharolytic Bacteria. These are organisms found in water 

 that produce fermentation in sugar broth and form acids, but 

 do not give the reaction for indol. Rivas has perfected some 

 chemical tests that he claims distinguish this group from true 

 Bacillus coli, but whether they possess any different pathogenic 

 properties has not been determined. 



Bacillus Botulinus (Van Ermengem) . An anaerobic ba- 

 cillus cultivated by Van Ermengem in 1896 from ham which 

 had caused poisoning. 



Form. A large bacillus with rounded or spindle-shaped 

 ends, and often with oval terminal spores, motile, with lateral 

 flagella. 



