378 



TETANUS. 



4 /*< to 5 fji in length and .4 /A in thickness, with somewhat rounded 



ends. Besides occurring as short rods it also develops filamentous 



forms, the latter 



. % being more com- 



mon in fluid me- 



A **^ * dia. It stains 



readily by any of 

 the usual stains 

 and also by 

 Gram's method. 

 A feature in it 

 is the uniform- 

 ity with which 

 the protoplasm 

 stains. It is very 

 slightly motile, 

 and its motil- 

 ity can be best 

 studied in an 

 anaerobic hang- 

 ing-drop prepa- 

 ration (p. 69). 



When stained by the special methods already described, it is 



found to possess numerous delicate flagella attached both at 



the sides and at the ends (Fig. 



127). These flagella, though 



they may be of considerable 



length, are usually curled up 



close to the body of the bacillus. 



The formation of flagella can 



be best studied in preparations 



made from surface anaerobic 



cultures (p. 66). As is the 



case with many other anaerobic 



flagellated bacteria the flagella, 



on becoming detached, often 



become massed together in the 



form of spirals of striking ap- 

 pearance (Fig. 128). At incuba- 

 tion temperature B. tetani readily forms spores, and then presents 



t 



FlG. 127. Tetanus bacilli, showing flagella. 

 Muir's method. X 1000. 



Stained by Rd. 



FlG. 128. Spiral composed of numerous 

 twisted flagella of the tetanus bacillus. Stained 

 by Rd. Muir's method. X 1000. 



