BACILLUS TETANI 91 



the slowly motile vegetative cells described above, 

 with, however, a few spore-bearing bacilli. Should 

 the culture be older, a cover-glass preparation will 

 show the appearance represented an Fig. 94, in 

 which the great majority of the bacilli possess a 

 spherical, strictly terminal spore of considerably 

 greater diameter than the bacillus itself, giving rise 

 to the " drum-stick " appearance so characteristic of 

 this organism. The length of these spore-bearing 

 bacilli is very variable, and the protoplasm, by its 

 vacuolation and irregularity of staining, shows signs 

 of degeneration. At the left-hand side is seen a 

 non-spore-bearing filamentous form. 



The bacillus grows between the temperatures 

 14 C. and 43 C. Its optimum is about 37 C. 

 Spore formation begins at 20 C. and ceases at 42 C., 

 and is rapid at about 37 C. Should such a culture be 

 inoculated by means of a pipette into the depths of 

 a glucose gelatine tube, whose surface is then melted 

 so as to close the track of the inoculation, and whose 

 mouth is sealed or covered with india-rubber, then, 

 if kept at 21 c C., a growth such as is represented in 

 Fig. 95 will be obtained. The growth consists of a 

 series of fine filaments radiating from the lower part 

 of the inoculation track, penetrating the gelatine, 

 and finally, but slowly, causing liquefaction, without, 



