672 Bacillus Coli 



at the time the culture is taken, and does not appear to be propor- 

 tionate to the ulterior gravity of the case. 



The mobility of Bacterium coli is, in general, proportionate to its 

 virulence. The jumping movement, nevertheless, does not correspond 

 to an exalted virulence in comparison with the cases in which the 

 mobility was very considerable, without presenting these jumping 

 movements. 



The virulence of Bacterium coli found in the blood and other organs 

 is identical with that of Bacterium coli taken from the intestines of the 

 individual. 



Lesage,* in studying the enteritis of infants, found that 

 in 40 out of 50 cases depending upon Bacillus coli the blood 

 of the patient agglutinated the cultures obtained, not only 

 from his own stools, but from those of all the other cases. 

 From this uniformity of action Lesage suggests that the 

 colon bacilli in these cases are all of the same species. 



The agglutinating reaction occurs only in the early stages 

 and acute forms of the disease. 



Immunization. It is not difficult to immunize an 

 animal against the colon bacillus. Loffler and Abel im- 

 munized dogs by progressively increased subcutaneous 

 doses of live bacteria, grown in solid culture and suspended 

 in water. The injections at first produced hard swellings. 

 The blood of the immunized animals possessed an active 

 bactericidal effect upon the colon bacteria. The serum 

 was not in the correct sense antitoxic. 



Differential Diagnosis. This problem is considered at 

 greater length under the heading "Cultural Differentiation 

 of the Bacillus Typhosus" (q.v.). For the recognition of the 

 colon bacillus the most important points are the motility, 

 the indol-formation, the milk-coagulation, and the active 

 gas-production. As, however, most of these features are 

 shared by other bacteria to a greater or less degree, the most 

 accurate differential point is the immunity reaction with the 

 serum of an immunized animal, which protects susceptible 

 animals from the effects of inoculation, and produces a simi- 

 lar agglutinative reaction to that observed in connection with 

 the blood and serum of typhoid patients, convalescents, and 

 immunized animals. 



The fact that, with rare exceptions, the typhoid serum 

 produces a specific reaction with the typhoid bacillus, and 

 the colon serum with the colon bacillus, should be the most 

 important evidence that they are entirely different species. 



What is commonly known as Bacillus coli communis is, 

 no doubt, not a single species, but a group of bacilli too 

 * "La Semaine Medicale," Oct. 20, 1897. 



