BACILLUS DIPHTHERIiE 527 



Other Bacilli Morphologically Resembling the Diphtheria Bacillus. — 



Many bacilli have been described which have a slight morphological 

 resemblance to Bacillus diphtheriae but which have little or no patho- 

 logical significance. Such organisms are met with in milk, air, and 

 water, and as secondary invaders together with other bacteria in old 

 discharging wounds. These bacilli are usually larger than the diph- 

 theria bacillus and, although transversely striped, rarely show polar 

 bodies. On the various media they grow heavily on even the simpler 

 nutrient substances, with heavy, usually white or yellowish-white colo- 

 nies. Culturally they show all the qualities of saprophytes. Inoculated 

 into animals they produce at most a mUd local reaction. In the litera- 

 ture these organisms have often been loosely spoken of as " Pseudodiph- 

 theria" bacilli, a term which is inappropriate since they have nothing 

 in common with the Klebs-LoefHer bacillus except a certain morpholog- 

 ical resemblance. Differentiation is never difficult. 



