PATHOGENIC BACTERIA. 26l 



mals, and is not demonstrated in cultures. This bacillus is 

 not motile. It does not form spores. It stains with the ordi- 

 nary aniline dyes, but does not stain by Gram's method. It 

 is aerobic and facultative anaerobic. It may be cultivated 

 at ordinary temperatures, but grows better in the incubator. 

 It does not liquefy gelatin. Stick-cultures in gelatin develop 

 especially at the point where the puncture enters the surface 

 of the gelatin, making what is called a " nail-shaped " 

 growth; the growth in gelatin is white; in old cultures the 

 gelatin acquires a brown color. It develops also on the other 

 media. Dextrose and lactose are fermented by it ; in cultures 

 on potato, gas is formed; milk is not coagulated. It does 

 not produce indol. 



The thermal death-point is about 56 C. It is patho- 

 genic for mice, less so for guinea-pigs and rabbits. This 

 bacillus is sometimes found in the healthy mouth and nose. 

 It has been known to cause inflammation, especially in the 

 vicinity of the mouth, nose and ear, broncho-pneumonia, 

 and more rarely empyema and meningitis. It was described 

 by Friedlander as the specific cause of lobar pneumonia. 

 Subsequent investigations indicate that it is comparatively 

 seldom found in pneumonia. 



There are various capsulated bacilli (capsule bacilli of 

 R. Pfeiffer and others) which closely resemble the bacillus 

 of Friedlander, and at least belong to the same group. The 

 bacillus of ozaena, which has often been found in that dis- 

 ease is very similar. B. lactis aerogenes and B. coli com- 

 munis also have many points in common with the Fried- 

 lander bacillus. 



Bacillus of Rhinoscleroma. A short bacillus with 

 rounded ends, often united in pairs, also growing to a 

 greater length ; surrounded by a capsule ; not motile ; stained 

 by the ordinary aniline dyes. It is much like the bacillus 

 of Friedlander, but some writers have said that it is not so 



