508 PATHOGENIC BACTERIA. 



tions connected with the intestines, as, for example, 

 appendicitis. 



It is a question whether the colon bacillus is always 

 virulent, or whether it becomes virulent under abnormal 

 conditions. Klencki 1 found that it was very virulent in 

 the ileum, and less so in the colon and jejunum, espe- 

 cially in dogs. He also found that the virulence was 

 greatly increased in a strangulated portion of intestine. 

 Other observers, as Dreyfuss, found that the colon bacil- 

 lus as it occurs in normal feces is non-pathogenic. Most 

 experimenters, however, believe that pathological con- 

 ditions, such as disease of the intestine, ligation of the 

 intestine, etc., cause increased virulence. 



Adelaide Ward Peckham, in an elaborate study of the 

 " Influence of Environment on the Colon Bacillus," 2 con- 

 cludes that while the conditions of nutrition and develop- 

 ment in the intestine seem to be most favorable, the colon 

 bacillus is ordinarily not virulent, because " its first force 

 is spent upon the process of fermentation, and as long as 

 opportunities exist for the exercise of this function the 

 affinities of this organism appear to be strongest in this 

 direction. 



"Moreover, the contents of the intestine remain acid 

 until they reach the neighborhood of the colon, and by 

 that time the tryptic peptons have been formed and 

 absorbed to a great extent. 



"During the process of inflammation in the digestive 

 tract a very different condition may exist. The peptic and 

 tryptic enzymes may be partially suppressed. Fermenta- 

 tion of carbohydrates and proteid foods then begins in 

 the stomach, and continues after the mass of food is 

 passed on into the intestine. The colon bacillus cannot, 

 therefore, spend its force upon fermentation of sugars, 

 because they are already broken up and an alkaline fer- 

 mentation of the proteids is in progress. It also cannot 

 form peptons from the original proteids, for it does not 



1 A tin. de I 'Inst. Pasteur, 1895, No. 9. 



2 Journal of Experimental Medicine, Sept., 1897, vol. ii., No. 4, p. 549. 



