524 Bacilli Resembling the Typhoid Bacillus 



whitish expansions with irregular margin, which are actively motile 

 when examined in the hanging drop from young surface colonies taken 

 from gelatin plates, which coagulate milk within a few days ; grow upon 

 potato, either as a rich pale or brownish-yellow deposit, or merely 

 as a glistening, barely recognizable layer, and which give a distinct 

 indol reaction. Their behavior in the fermentation-tube must conform 

 to the following scheme: 



" Variety a: 



"One per cent, dextrose-bouillon (at 37 C.). Total gas approx- 

 imately \ ; H CO 2 approximately 2:1; reaction strongly acid. 



"One per cent, lactose-bouillon: as in dextrose-bouillon (with slight 

 variations). 



"One per cent, saccharose-bouillon; gas-production slower than 

 the preceding, lasting from seven to fourteen days. Total gas about 

 ; H CO 2 = nearly 3:2. The final reaction in the bulb may be 

 slightly acid or alkaline, according to the rate of gas-production. 



"Variety ft: 



"The same in all respects, excepting as to its behavior in saccharose- 

 bouillon; neither gas nor acids are formed in it." 



DIFFERENTIAL CHARACTERISTICS. 



TYPHOID BACILLUS. 



Bacilli usually slender. 



Flagella numerous (10-20), long, 

 and wavy (peritricha). 



Growth not very rapid, not par- 

 ticularly luxuriant. 



Upon Eisner's, Hiss', Piorkow- 

 ski's, and other media gives 

 characteristic appearances. 



Upon fresh acid potato the so- 

 called "invisible growth" form- 

 erly thought to be differential. 



Acid-production in whey not ex- 

 ceeding 3 per cent. Sometimes 

 slight in ordinary media, and 

 succeeded by alkali-production. 



Grows in media containing sugars 

 without producing any gas. 



Produces no indol. 



Growth in milk unaccompanied 



by coagulation. 

 Gives the Widal reaction with the 



serum of typhoid blood. 



COLON BACILLUS. 



Bacilli a little thicker and shorter. 

 Flagella fewer (8-10) (peritricha). 



Growth rapid and luxuriant. This 

 character is by no means con- 

 stant. 



Upon Eisner's, Hiss', Piorkow- 

 ski's, and other media gives 

 characteristic appearances. 



Upon potato a brownish-yellow 

 distinct pellicle. 



Acid-production 

 throughout. 



well marked 



Fermentation with gas-produc- 

 tion well marked in solutions 

 containing dextrose, lactose, or 

 saccharose, the usual formula 

 being H CO 2 = 2 : 1. 



Indol-production marked. 



Milk coagulated. 



Does not react with typhoid 

 blood. 



BACILLUS ENTERITIDIS (GARTNER). 



General Characteristics. A motile, flagellated, non-sporogenous, 

 non-chromogenic, non-liquefying, aerobic and optionally anaerobic, 

 pathogenic bacillus staining by the ordinary methods, but not by 

 Gram's method. 



