358 BACTERIOLOGY. 



years a great deal has been written concerning the 

 possible pathogenic nature of this organism. 



The fact that it is always with us in most intimate 

 association with certain of our life-processes, together 

 with the fact that it is known to appear in organs other 

 than that in which it is normally located, and that its 

 occurrence in diseased conditions is not rare, justifies the 

 opinion that it is one of the most important of the 

 micro-organisms with which we have to deal. 



While not generally considered to be a pathogenic 

 organism, there is, nevertheless, sufficient evidence to 

 warrant the statement that, under favorable conditions, 

 with which we are not entirely familiar, this organism 

 may assume pathogenic properties and that its presence 

 in diseased conditions is not always to be considered as 

 accidental, though this is frequently the case. 



The morphological and cultural peculiarities of the 

 bacterium coli commune are as follows : 



Morphology. In shape it is a rod with rounded ends, 

 sometimes so short as to appear almost spherical, while 

 again it is seen as very much longer threads. Often 

 both forms will be associated in the same culture. It 

 may occur as single cells or as pairs, joined end-to-end. 



There is nothing to be said of its morphology that 

 can aid in its identification, for in this respect it simu- 

 lates many other organisms. It is usually said to be 

 motile, and undoubtedly is motile in the majority of 

 cases, but its movements are so sluggish that a positive 

 opinion is often difficult. 



By Loeffler's method of staining, flagella can be 

 demonstrated, though not in such numbers as are seen 

 to occur on the typhoid fever bacillus. 



It does not form spores. 



