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 . in 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, 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, 



