BACILLUS TETANI 



373 



very characteristic appearance. The spores are round, and in 

 diameter may be three or four times the thickness of the bacilli. 

 They are developed at one end of a bacillus, which thus assumes 

 what is usually described as the drumstick form (Figs. 124, 127). 

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

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



FIG. 124. Film preparation of discharge from wound in a case of tetanus, 

 showing several tetanus bacilli of "drumstick" form. (The thicker 

 bacillus with oval and not quite terminal spore, in the upper part of the field 

 towards the right side, is not a tetanus bacillus but a putrefactive 

 anaerobe which was obtained in pure culture from the wound.) 

 Stained with gentian -violet. x 1000. 



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 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 



