166 



APPLIED BACTERIOLOGY 



BACILLUS TYPHOSUS. 



BACILLUS COLI COMMUNIS. 



Gelatine 

 plates. 



The colonies on the sur- 

 face form large gra3dsh- 

 white expansions with 

 irregular edges, and after 

 a time become somewhat 

 yellowish - brown. The 

 depth colonies are darker, 

 with regular edges. Un- 

 der a low power the 

 colonies exhibit a char- 

 acteristic woven struc- 

 ture. 



The gelatine is not 

 liquefied. 



The colonies are round 

 and oval, with smooth- 

 rimmed margins. The 

 surface colonies form 

 dirty - white expansions, 

 which on magnification 

 exhibit a furrowed ap- 

 pearance. The colonies 

 later become dirty yellow- 

 ish-brown in colour. 



The gelatiae is not 

 liquefied. 



Gelatine 

 streak 

 culture. 



Produces a grayish- 

 white expansion with 

 irregular edges. - The 

 growth often has a bluish 

 iridescence. 



Dirty yellowish - white 

 expansion, which does not 

 spread aU over the surface 

 of the media, and often 

 has a bluish iridescence 

 when viewed by trans- 

 mitted light. 



Gelatine 



shake 



culture. 



No gas bubbles. 



Copious gas formation. 



Agar-agar 

 streak 

 culture. 



Grayish - white expan- 

 sion, which covers the 

 surface of the medium. 



Dirty yellowish - white 

 expansion, which spreads 

 over the surface of the 

 medium. 



Potatoes. 



Generally a faint gray- 

 ish - white growth ; the 

 growth, varies, however, 

 on different potatoes. 



Slimy yellowish growth. 



Milk. 



Turns faintly acid. No 

 coagulation takes place. 



Curdled after one to 

 three days. 



Broth. 



Gives no indol reac- 

 tion. 



Gives a well - marked 

 indol reaction after from 

 twenty-four to forty-eight 

 hours. 



Widal's 



typhoid serum 



reaction. 



Agglutination of bacilli. 



No change. 



