354 



TETANUS. 



slender rods, without presenting any characteristic features. 

 There is usually present in such pus a great variety of 

 other organisms cocci and bacilli. The characters of the 

 bacillus are, therefore, best studied in cultures. It is then 

 seen to be a slender organism, usually about 4 /x to 5 



length and .4 



- 

 ^ 



\ 



n 

 in 



thickness, with some- 

 what rounded ends. 

 It occurs singly or 

 in threads, the latter 

 being more common 

 in fluid media. It 

 stains readily by any 



^ , -> f tne usual stains 



\ \t v 'N. and also by Gram's 



/ m- method. A feature 



in it is the uniformity 

 with which the proto- 

 plasm stains. It is 

 very slightly motile, 

 and its motility can 

 be best studied in 

 a hanging -drop pre- 

 paration kept on a 



warm stage. When stained by the special methods already 

 described, it is found to possess flagella of considerable length, 

 either at both ends or all round (Kanthack). At incubation 

 temperature it readily forms spores, and then presents a very 

 characteristic appearance. The spores are round, and in dia- 

 meter 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. 87, 88). In 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, they may become 



FIG. 88. Tetanus bacilli ; some of which 

 possess spores. From a culture in glucose 

 agar, incubated for three days at 37 C. 



Stained with carbol-fuchsin. x 1000. 



