l8o ESSENTIALS OF BACTERIOLOGY 



CHAPTER XXV 



ANAEROBIC BACTERIA (BACILLUS OF TETANUS; BACILLUS 

 OF MALIGNANT EDEMA, ETC.) 



SIMILAR in form and cultural requirements are a group of 

 bacteria which are found as a result of injury or the infection 

 of wounds. They vary greatly in the clinical symptoms 

 produced. 



Bacillus of Tetanus (Nicolaier-Kitasato) . Origin. 

 Nicolaier found this bacillus in the pus of a wound in one 

 who had died of tetanus, describing it in 1884. 



Kitasato isolated and cultivated this germ (1889). 



Form. A very slender rod. 



When the spores form, a small swelling occurs at the spore 

 end, giving the bacillus a drum-stick shape (Fig. 89). 



Properties. Not very motile, though distinctly so; lique- 

 fies gelatin slowly. The cultures give rise to a foul-smelling 

 gas. 



Growth. Develops very slowly, best at 36 to 38 C, and 

 only when all oxygen is excluded an obligatory anaerobin. 

 In an atmosphere of hydrogen it nourishes. 



Colonies on gelatin plates hi an atmosphere of hydrogen. 

 Small colonies. After four days a thick center and radiating, 

 wreath-like periphery, like the colonies of Bacillus subtilis. 

 Pure cultures not easy to obtain (Fig. 90) . 



High Stab-culture. The gelatin having 2 per cent, glucose 

 added and filling the tube. Along the lower portion of the 

 needle-track, a thorn-like growth, little needle-like points 

 shooting out from a straight line. The whole tube becomes 

 clouded as the gelatin liquefies, and then the growth settles 

 at the bottom of the tube (Fig. 91). 



A gar. On agar, in the incubator, the growth is quite 

 rapid, and at the end of forty-eight hours gas-bubbles have 

 formed and the growth nearly reached the surface. 



