BACILLUS TETANI 



41 



a specimen stained with a watery solution of gentian-violet or 

 methylene-blue, the spores are uncoloured except at the periphery, 

 so that the appearance of a small ring is produced ; if a powerful 

 stain such as carbol-fuchsin be applied for some time, the spores 

 become deeply coloured like the bacilli. Further, especially if 



^ 



Fio. 120. Film preparation of discharge from wound in a case 

 of tetanus, showing several tetanus bacilli of "drumstick" form. 

 (The thicker bacillus present is not a tetanus bacillus, but a 

 putrefactive anaerobe which was obtained in pure culture from the 

 wound. ) 



Stained with gentian -violet, x 1000. 



the preparation be heated, many spores may become free from the 

 bacilli in which they were formed. 



Isolation. The isolation of the tetanus bacillus is somewhat 

 difficult. By inoculation experiments in animals, its natural 

 habitat has been proved to be garden soil, and especially the 

 contents of dung-heaps, where it probably leads a saprophytic 

 existence, though its function as a saprophyte is unknown. From 

 such sources and from the pus of wounds in tetanus, occurring 

 naturally or experimentally produced, it has been isolated^by 



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