166 BACILLUS COLI COM MUNIS. 



that tract. In pathological conditions it is met with, in asso- 

 ciation with other bacteria, a. In acute enteritis, cholera 

 morbus, in certain forms of dysentery ; it is easily demon- 

 strable in large numbers, and has been thought by some to 

 be the cause of those diseases, but this is not so. Its pres- 

 ence in the healthy individual in nearly all cases is sufficient 

 to show the falsity of this position. 6. It has also been 

 found in cases of peritonitis, endocarditis, and in suppurating 

 inflammation of the liver and the kidney. At autopsies it 

 occurs in various organs and in nearly all conditions. Asso- 

 ciated with specific microorganisms it has also been proved 

 to exist in the blood of patients in articulo mortis. Outside 

 the human body it has been discovered in water and soil con- 

 taminated with fecal matter. 



Etiologic Relations. For a long time this bacillus was 

 looked upon as a harmless saprophyte : latterly experiments 

 have established the fact that it is often the cause of inflam- 

 matory conditions in the body, and that in a number of other 

 instances it is pathogenic from the fact that it Jowers the 

 vitality of the body and enables other germs to act delete- 

 riously. 



Morphology. This bacillus is polymorphous and very 

 closely resembles the typhoid bacillus in shape. It is a rod 

 with rounded extremities, in very young cultures appearing 

 almost oval with a bright centre. Later on the bacilli coa- 

 lesce and appear as long threads. They possess flagella ; not 

 so numerous, however, as the Bacillus typhosus. These fla- 

 gella may be stained by the Loeffler method. It has no 

 spores and stains by all the ordinary anilin dyes, but not by 

 the Gram method. 



Biologic Characters. It is aerobic and facultative anaerobic. 

 It is motile at times, and at other times appears to be motion- 

 less. Its motility is always of the sluggish kind. Cultures 

 which when young contain organisms with decided motion, 

 have on being kept for some time shown that the bacilli have 

 lost their motility. It grows on all the artificial culture- 

 media and at the temperature between 10 and 40 C. Its 

 growth, though retarded at the temperature above 40 C., 



