CHAPTER VI. 



THE BACILLI OF THE COLON, TYPHOID, 

 DYSENTERY GROUP. 



THESE organisms are usually grouped together 

 because of the similarity in their appearance and 

 manner of growth upon artificial culture media. All 

 the members of this group are short, rod-shaped, often 

 forming chains, but never forming spores. They are 

 all motile. 



Under the name of colon bacilli are grouped a 

 number of varieties very closely related, which are bacillus 

 usually harmless parasites living in the bodies of man 

 and animals, but which at times become pathogenic 

 and cause infection. The colon bacillus itself, prop- 

 erly called the Bacillus coli communis, is a constant 

 inhabitant of the intestine in man and animals. In 

 nature it is commonly found in soil, air, water, and 

 milk. Just what function it performs in the intestine 

 is not known positively, but it probably assists in 

 breaking down food materials into simpler form so 

 that they can be absorbed. 



Once the colon bacillus has invaded the walls of 

 the intestine, it is capable of setting up an infection. 

 It has been found to be the cause of abscess of the 

 liver, inflammations of the gall-bladder, the urinary 

 bladder, the pelvis of the kidney, and the pancreas. It 

 is frequently the cause of peritonitis in cases of rup- 



(55) 



