THE DIPHTHERIA BACILLUS 187 



Bacillus Xerosis. Diphtheria-like bacilli were found by 

 Hutschert and Neisser in 1904 in a chronic form of conjunctivitis 

 known as xerosis, which they believed to be the causal agent. 

 Since then the organism has so frequently been isolated from nor- 

 mal eyes that it is no longer considered as the cause of the disease. 

 Morphologically it is almost identical with the diphtheria bacillus. 

 It differs from B. diphtherise and B. Hoffmanni in its ability to 

 ferment sugars, but it resembles the latter in that it produces no 

 toxin and is non-pathogenic for animals. 



Still other organisms exist which closely resemble the diphtheria 

 bacillus structurally. They are apparently numerous and have 

 been found both in normal and diseased conditions, although 

 it is considered somewhat doubtful whether they ever incite dis- 

 ease. As yet no classification of these organisms has been made 

 and they are grouped together under the term Diphtheroids. 



