206 BACTERIOLOGY 



Gelatin stab. A good growth in depth ; surface growth flat, spreading. 



Agar slant. Growth gray, white, moist, glistening, translucent., 



Potato. Growth yellowish to yellowish brown. 



Bouillon. A dense turbidity, with a heavy sediment. 



Milk. Coagulated. 



Litmus milk. Reduced, acid. Cultures have a faecal odor. H 2 S produced. 



Lactose bouillon. Much gas. 



Saccharose bouillon. Gas may or may not be produced; acetic, formic, and 

 lactic acids produced. In bouillon, ammonia produced, and an p^Jjjj^ 

 reaction. 



Pathogenesis. Variable; inoculation of mice with o.i-i.o cc. of a bouillon 

 culture, intraperitoneally, causes death in 1-8 days ; bacilli in the blood, 

 and peritoneal exudate. One cc. of virulent varieties inoculated intra- 

 peritoneally into guinea pigs may cause death, with general peritonitis. 



Habitat. In the intestines of man and animals, faeces, water, milk. Asso- 

 ciated with a number of pathologic conditions peritonitis, cystitis, 

 cholera-nostras, etc. 



VARIETIES 



B. coli-dysentericum Ciechanowski : Centralblatt f. Bakteriol., XXIII, 445, 



1898. 



For varieties of B. coli see Pfaundler : Centralblatt f. Bakteriol., XXIII, i. 

 Pottien : Zeitsch. f. Hygiene, XXII, Heft i, describes a variety of B. coli 



which in the animal body shows a capsule, which gives B. Zopfi-Xfct 



colonies, and which is strongly pathogenic to mice. 



. 3. B. Wardii 



Gas and taint producing Bacillus in cheese curd: Cornell . Univ. Ag. Expt. Station, 



Bull. 158, 1899. 



Morphology. Bacilli in bouillon 1.2-2 4 /u,. with rounded ends ; occur singly. 

 Show a polar stain with carbol fuchsin, stain feebly but uniformly, with 

 alk'aline methyl-blue. Not stained by Gram's method. Flagella demon- 

 strated. Optimum temperature 35-38. Facultative anaerobic. 



Gelatin colonies. Surface: thin, spreading, 3-7 mm., wrinkled; border irreg- 

 ular. Microscopically, centre opalescent, border thin, translucent. 



Gelatin stab. In depth, growth beaded ; on the surface, growth thin, 

 spreading. 



Agar colonies. At 37. Deep colonies: lenticular, 0.5-1.0 //,, grayish. Sur- 

 face colonies: round, flat, entire, sharp, gray, moist, glistening, 2-4 mm. ; 

 not viscid. Have the odor of swine-plague cultures. 



