204 BACTERIOLOGY FOR NURSES 



twenty-four to forty-eight hours. There is a rapid decline in 

 temperature, and finally the development of a fibrino-purulent 

 peritonitis, due undoubtedly to the endotoxins liberated from 

 the disintegrating bacteria. 



In man they are considered as the cause of the majority of 

 cases of cystitis and should such an infection spread they may 

 give rise to pyelitis or suppurative nephritis. They have been 

 isolated from abscesses of the liver and gall-bladder. Numerous 

 epidemics of diarrhea in young children, cases of broncho-pneu- 

 monia, pleurisy, meningitis, and endocarditis, have also been 

 attributed to them. In ulcerative conditions of the intestines 

 they may readily pass through the injured intestinal walls and 

 with associated organisms give rise to peritonitis. Ordinarily in 

 such cases streptococci and staphylococci are also present, and it 

 is probable that the latter are more actively concerned in produc- 

 ing the lesions. Shortly before death the colon bacilli frequently 

 pass through the intact intestinal mucosa into the circulation. 



It is somewhat surprising that an organism constantly present 

 in such large numbers in the intestines should at times give rise 

 to disease; it might naturally be expected that the body cells 

 had developed a complete state of immunity towards it. A 

 number of explanatory suggestions have been offered. It may 

 be that none of the toxic products of the bacilli are absorbed 

 through the intact mucous membranes, in which case no process 

 of immunization would be likely to occur ; or, on the other hand, 

 it may be that temporary lowered resistance may permit the 

 organisms to overcome the forces by which they have previously 

 been held in check. 



Immunity. Bacteriolytic and agglutinating antibodies are 

 produced in animals following injections of gradually increasing 

 doses of living or dead organisms. The normal serum of animals 

 and man will frequently agglutinate B. coli in dilutions as high as 

 1 in 10 or 1 in 20. The formation of such agglutinins may probably 

 be the result of their habitual presence in the intestinal tract. 

 The serum of patients recovering from typhoid fever or dysentery 

 will agglutinate B. coli in even higher dilutions. The fact may be 



