SUSCEPTIBLE ANIMALS. 



421 



on the average shorter than the bacillus of mouse septicaemia. The 



bacilli are solitary, or in pairs the elements of which are often united 



at an angle ; occasionally a chain 



of three or four elements may be 



observed, and in old cultures the 



bacilli may grow out into short 



threads which are straight or more 



or less curved and twisted. Small 



refractive bodies may sometimes 



be distinguished in the rods, and 



these have been supposed by some 



authors to be spores, but this has 



not been demonstrated. 



This bacillus stains readily 

 with the ordinary aniline staining 

 agents and also by Gram's method. 



Bioloqical Characters. A FlQ - Ise.-Bacillus of rouget, from a pure 

 ,. , f 7 . 7 . culture. X 1,000. From a photomicrograph. 



facultative anaerobic, non-hque- ( Roux .) 

 fying bacillus. According to 



Schottelius, the rothlauf bacilli are sometimes mo- 

 ^utf^^M tile, but Fliigge states that other observers have 



oo 



not seen them in active motion. Frankel says 

 they have the power of voluntary motion. Eisen- 

 berg says that the bacillus of mouse septicaemia is 

 motionless, and Frankel says " they seem to be in- 

 capable of voluntary motion/' Baumgarten re- 

 marks : "Whether the bacilli exhibit voluntary 

 movements has not been determined/' Although 

 this bacillus is not strictly anaerobic, it grows 

 better in the absence of oxygen than in its pre- 

 sence. Development occurs in various culture me- 

 dia at the room temperature, but is more rapid in 

 the culture oven. In gelatin stick cultures no 

 development occurs upon the surface, but the 

 growth along the line of puncture is very charac- 

 teristic; this consists of a delicate, cloud-like, ra- 

 diating growth, which extends, in the course of a 

 few days, almost to the walls of the test tube. 

 The rothlauf bacillus does not extend so rapidly 

 through the gelatin, and the branching, cloud-like 

 growth is not as delicate; Fliigge compares it to 

 the brush of bristles used for cleansing test tubes. 

 In old cultures in nutrient gelatin a slight soften- 

 ing of the gelatin occurs along the line of growth, and as a result of 



FIG. 137. Bacillus of 

 mouse septicaemia ; 

 culture in nutrient gela- 

 tin, end of four days at 

 18 C. (Baumgarten.) 



