266 VETERINARY BACTERIOLOGY 



White scours, or diarrhea in calves, is the most important of 

 the diseases of animals that have been attributed to B. coli. Differ- 

 ent strains showing differences in agglutination have been isolated 

 from various outbreaks. Moore and Nocard believe that the 

 organism enters the body soon after birth through the ruptured 

 umbilical cord coming in contact with fecal material. Investiga- 

 tors are by no means in accord in attributing this disease to B. coli. 

 The etiologic relationship of this organism cannot be considered 

 as settled. 



Immunity. A considerable degree of immunity to B. coli 

 may be induced by injections of cultures, killed or living. Ag- 

 glutinins are present in normal serum, but may be greatly in- 

 creased by systematic immunization. Specific precipitins for 

 the bacterial proteins are present in the immune serum. Opsonins 

 are present in normal serum. The body has naturally a high 

 degree of immunity against the B. coli. This may be accounted 

 for by the presence of B. coli in the intestines and the continued 

 opportunity for infection. 



Bacteriologic Diagnosis. The isolation of the characteristic 

 colonies upon litmus-lactose agar is the simplest and quickest 

 method of determining the presence of B. coli. Methods of 

 recognition and isolation from water will be discussed at greater 

 length under that heading. 



Bacillus lactis aerogenes 



Synonyms. Bacterium aerogenes; Bacillus pyogenes. 



Escherich, in 1885, described an organism which he isolated 

 from sour milk as B. lactis aerogenes. It has since been found 

 repeatedly in the intestinal contents of man and animals. It is 

 sometimes more abundant than Bacillus coli itself. 



Morphology and Staining. Bacillus lactis aerogenes differs 

 morphologically from the B. coli principally by the lack of flagella 

 and in the ability to produce capsules when grown in milk. 



Isolation and Culture. This organism may be isolated in the 

 same manner as B. coli upon litmus-lactose agar. The colonies 

 upon agar and gelatin are larger, thicker, and more slimy than those 

 of the colon bacillus. Milk is curdled more rapidly. In gelatin 

 stabs the growth along the streaks is filiform; that at the surface is 



