l8o ESSENTIALS OF BACTERIOLOGY 



Staining. Stains readily, negative to Gram; facultative 

 anaerobe. 



Growth. Best at 37 C. Killed by ten minutes' exposure 

 to 55 C. 



Gelatin. A white line of growth along puncture; super- 

 ficial growth slight. 



Bouillon. Uniform clouding. Indol usually not produced; 

 milk not coagulated. 



Agar. Resembles typhoid bacillus. 



Potato. Thin whitish layer, turning light brown. 



No gas -formation in glucose or lactose media. 



Patho genesis. Mice and guinea-pigs die in one or two days 

 after intraperitoneal inoculation. Rabbits usually recover, 

 though lesions analogous to those of human dysentery have 

 been produced. Dogs die in five or six days, with well-marked 

 diarrhea. 



Products. The patient's blood-serum agglutinates the ba- 

 cillus in cases in which it can be cultivated from the stools. 

 The reaction is absent from other cases. Shiga has reduced 

 the mortality from 34.7 to 9 per cent, by means of a serum 

 obtained from immunized horses, but in more extensive tests 

 the antidysenteric serum proved of little value. 



Habitat. Found in the stools and in shreds of mucous mem- 

 brane from the intestinal walls. 



Bacillus Aerogenes Capsulatus (Welch, 18gl). Origin. 

 The intestine of man and animals, soil, sewage, and water. 



Form. A thick bacillus, 3 to 6 // in length, frequently capsu- 

 lated. 



Properties. Not motile, anaerobic, forms spores chiefly in 

 cultures on blood-serum. 



Growth. Best at 37 C. 



Gelatin. Liquefied slowly or not at all. 



Bouillon. Forms gas. 



Milk. Coagulated and becomes acid. 



Potato. Thin, grayish-white growth with gas-production. 



Forms gas in abundance on dextrose, lactose, or saccharose 

 media. 



