PATHOGENIC BACTERIA 171 



Colonies on gelatin plates in an atmosphere of hydrogen. 

 Small colonies. After four days a thick center and radiating 

 wreath-like periphery, like the colonies of Bacillus subtilis. 



High Stab-culture. The gelatin having 2 per cent, glucose 

 added and filling the tube. Along the lower portion of the 

 needle -track, a thorn-like growth, little needle-like points 

 shooting out from a straight line. The whole tube becomes 



Fig. 103. Bacillus of tetanus with spores. 



clouded as the gelatin liquefies, and then the growth settles at 

 the bottom of the tube. 



Agar. At brood-heat, on agar, the growth is quite rapid, and 

 at the end of forty-eight hours gas-bubbles have formed and the 

 growth nearly reached the surface. 



Bouillon. Adding glucose to the bouillon gives a medium in 

 which an abundant growth occurs. 



Cultivation from Spores. Kitasato, by exposing a portion of 

 suspected material to a temperature of 80 C. for one hour, 

 killed off all the spores save those of tetanus, which were then 

 cultivated. 



