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PATHOGENIC BACTERIA. 



Characteristics for Differentiation. 



TYPHOID BACILLUS. 



Bacilli usually slender. 



Flagella numerous (10-20), long, and 

 wavy. 



Growth not very rapid, not particularly 

 luxuriant. 



Upon Eisner's culture-medium de- 

 velops slowly, the colonies remain- 

 ing small. 



Upon fresh acid potato the so-called 

 " invisible growth " formerly thought 

 to be differential. 



Acid-production in whey not exceed- 

 ing 3 per cent. Sometimes slight 

 in ordinary media, and sometimes 

 succeeded by alkaline production. 



Grows in media containing sugars 

 without producing any gases. 



Produces no indol. 



Growth in milk unaccompanied by 

 coagulation. 



In Maassen's asparagin-glycerin solu- 

 tion the bacillus does not grow. 



Gives the Widal reaction with the 

 serum of typhoid blood. 



COLON BACILLUS. 

 Bacilli inclined to be a little thicker. 

 Flagella fewer (8-10). 



Growth rapid and luxuriant. This 

 character is by no means constant. 



Upon Eisner's medium develops more 

 rapidly, the colonies being larger. 

 (Sometimes the colonies are small 

 and remain so.) 



Upon potato a brownish-yellow, dis- 

 tinct pellicle. 



Acid-production well marked. 



Gas-production well marked. 



Indol-production marked. 

 Milk coagulated. 



Grows in Maassen's solution. 

 Does not react with typhoid blood, 



