432 Diphtheria 



mucous membranes than the conjunctiva; thus, Leber found it in the 

 mouth, the pelvis of the kidney, and in intestinal ulcers. From the 

 investigations of Sattler, Frankel and Franke, Schleich, Weeks, 

 Fick, Baumgarten, and others it appears that Bacillus xerosis is a 

 harmless saprophyte that is occasionally found upon the conjunctiva. 

 Happening to be found in xerosis it was accorded undue distinction. 



Morphology. — ^It resembles Bacillus diphtherise very closely, but 

 is probably a little shorter. The ends are clubbed, and in them meta- 

 chromatic bodies are stained by Neisser's and Roux's methods. 



There is no motility; there are no flagella and no spores. 



Cultivation. — Upon Loffler's medium and other media commonly 

 used for the diagnosis of diphtheria, the organism grows with so close 

 resemblance to the Bacillus diphtherise as to make the differentiation 

 difficult. Transplanted to other media, it continues to resemble 

 B. diphtheriae. 



Chemistry. — The organism is incapable of forming any toxin. 

 It ferments sugars like Bacillus diphtheriae, with the exception of 

 saccharose, which B. xerosis ferments, but which B. diphtheriae 

 cannot ferment. B. xerosis also fails to ferment dextrin, which B. 

 diphtheria ferments. 



These sugar-decomposing properties form the most reliable 

 methods of differentiating Bacillus diphtheriae, B. hofmanni, 

 and B. xerosis. 



Pathogenesis. — The organism is not pathogenic for man and is 

 certainly not the cause of xerosis. It is not toxicogenic and is not 

 known to be pathogenic for any animal. 



