132 ESSENTIALS OF BACTERIOLOGY. 



large spores which cause the rods to become spindle- or drum- 

 stick-shaped. 



Properties. Very motile ; liquefy gelatine ; do not produce 

 any foul gaseous products in the body. 



Growth. Grow rapidly, but only when the air is excluded, 

 and best at brood or body heat. 



Roll Cultures. (After Esmarch's method.) Small, round 

 glancing colonies with fluid contents, under low power, a mass 

 of motile threads in the centre, and at the edges a wreath-like 

 border. 



High Stab Culture, With glucose gelatine, the growth at first 

 seen in the bottom of the tube, with a general liquefaction of 

 the gelatine, gases develop anda somewhat unpleasant odor. 



Agar. The gases develop more strongly in this medium, and 

 the odor is more prominent. 



Guinea-Pig Bouillon. In an atmosphere of hydrogen cloud- 

 ing of the entire culture medium without any flocculent pre- 

 cipitate until third day. 



Staining. Are stained with the ordinary dyes, but Gram's 

 method is not applicable. 



Pathogenesis. When experiment animals, mice or guinea- 

 pigs, are injected with a pure culture under the skin they die in 

 8 to 15 hours, and the following picture presents itself at the 

 autopsy : In guinea-pigs from the point of infection, spreading 

 over a large area, an oedema of the subcutaneous tissues and 

 muscles, which are covered and saturated with a clear red 

 serous exudate free from smell. This contains great quantities 

 of bacilli. 



The spleen is enlarged, especially in mice. The bacilli are 

 not found in the viscera, but are present in great numbers on 

 the surface, Ce., in the serous coverings of the different organs ; 

 though when any length of time has elapsed between the death 

 of the animal and the examination, they can be found in the 

 inner portions of the organs, for they grow well upon the dead 

 body. In man they have been found in rapidly spreading gan- 

 grene. They are present in the soil, in putrefactions of various 

 kinds, and in dirty water. 



Immunity. Is produced by injection of the sterilized cul- 



