NON-PATHOGENIC BACTERIA. 22/ 



Bacillus acidi lactici (Hueppe). Found in sour milk; a 

 short, plump rod; not motile; does not liquefy gelatin; 

 facultative anaerobic; grows on the ordinary media; in 

 milk causes development of lactic acid with precipitation 

 of casein and production of gas and alcohol. It belongs in 

 the same group as B. coli communis and B. lactis aerogenes 

 (see Part IV.). 



There are numerous other bacteria, such as the bacte- 

 rium acidi lactici, which cause the formation of lactic acid 

 in milk. 



Bacterium ureae. A short, thick bacillus with rounded 

 ends; net motile; aerobic; found in ammoniacal urine; 

 grows slowly at room temperature upon gelatin, which is 

 not liquefied ; decomposes urea, forms ammonium carbonate. 



Bacterium Zopfii. Found in the intestines of hens, in 

 water and in fecal matter; a bacillus .75 to i JJL broad and 2 

 to 5 /j. long ; may form threads. Actively motile ; does not 

 liquefy gelatin; aerobic; involution forms are often seen 

 and they have been described as spores; grows rapidly, 

 best at 20 C. upon gelatin; forms branching zoogloese. 

 It is a member of the same group as B. proteus (see Part 

 IV.)- 



Spirillum rubrutn. Found by Esmarch in the putrefy- 

 ing cadaver of a mouse; short spirals twice the breadth of 

 the cholera spirillum, usually with one to three turns; in 

 bouillon growing into long spirals ; motile with flagella ; 

 spore formation doubtful ; facultative anaerobic ; does not 

 liquefy gelatin; grows slowly, best at about 37 C. on the 

 ordinary media; produces a wine-red pigment only when 

 the air is excluded. 



Spirillum or Spirochaeta dentium. Found in the mouths 

 of healthy persons, on the margins of the gums when they 

 are covered with a dirty deposit; long spirals with several 

 windings uneven in thickness ; has not been cultivated. 



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