352 



MICROBIOLOGY 



BACILLUS VULGARIS (HAUSER) MIGULA. 



Synonyms. Proteus vulgaris Hauser; Bacillus proteiis 

 vulgaris. 



Place in nature. This bacillus was first discovered by 

 Hauser with other bacteria in putrefying substances. Bacil- 

 lus (Proteus) Zenkeri belongs to this group. These putrefy- 

 ing bacteria belong to the organisms previously described as 

 "Bacterium termo" referring to any motile bacteria found in 

 putrefying infusions. 



Morphology. Bacilli varying in size from 0.4 to 0.6 /x 

 broad and 1.0 to 1.4 /* long.. Shorter and longer forms have 

 been observed and also flexible filaments which are sometimes 

 more or less wavy or twisted like braids of hair. 



Staining. It stains 

 readily with fuchsin or 

 gentian violet. It is 

 Gram negative. 



Cultivation. It grows 

 readily on the ordinary 

 media. 



Agar. A rapidly 

 spreading, moist, thin 

 grayish-white growth 

 appears. 



Gelatin. The growth 

 on gelatin plates is very 

 characteristic. At the 

 end of ten or twelve 

 hours in a 5 c / ( gelatin at 

 room temperature, small, 

 round depressions are 

 observed, which contain 

 liquefied gelatin and a 

 whitish mass consisting 



of bacilli in the center. Under a low-power lens these depres- 

 sions are seen to be surrounded by a radiating zone composed 





Fig. 73. Colony of Bacillus vulgaris 

 four days old, cultivated at 20 C. 

 (Hauser). 



