GENUS BACILLUS 



329 



ture wounds. It is stated that in the New Hebrides the natives 

 poison (infect with tetanus bacilli) their arrow heads with 

 dirt taken from crab holes in the swamps. As it produces 

 spores it is quite resistant so that it has been found in old 

 mortar, dried soils, and in the feces of horses and cattle. 



Morphology. The bacillus of tetanus is a slender rod, 

 2 to 5 /A in length, and 0.3 to 0.8 /* in breadth. The vegetative 



forms, which occur chiefly 

 in young cultures, are 

 slightly motile and are seen 

 to possess 5 numerous peri- 

 trichial flagella, when 

 stained by special methods. 

 After twenty- four to forty- 

 eight hours of incubation, 

 the length of time depend- 

 ing somewhat on the na- 

 ture of the medium and the 

 degree of anaerobiosis, the 

 bacilli develop spores locat- 



Fig. 67. Bacillus tetani. 



ed at one end. Kanthack 



found in the study of the morphology of tetanus bacilli that 

 they occasionally developed true branched forms. 



As the cultures grow older the spore-bearing forms com- 

 pletely supersede the vegetative ones. Very old cultures con- 

 tain spore-bearing bacilli and spores only. 



Staining. The tetanus bacillus is easily stained by the 

 usual aniline dyes, and reacts positively to Gram's stain. 

 Flagella staining is successful only when very young cultures 

 are used. 



Cultivation. Bacillus tetani grows readily on ordinary 

 media under anaerobic conditions. A slighty alkaline reaction 

 is required. The addition of 1 to 1.5% glucose favors its 

 growth. It develops sparingly at the point of introduction 

 into the animal body and usually is accompanied by other 



5 Vottaler. Zeit. f. Hyg., Bd. XXVII (1898) p. 480. 



6 Kanthack. Jour, of Path, and Bact., Vol. IV (1896) p. 452. 



