BACILLUS DIPHTHERIA 



525 



animals. B. Hoffmann! forms no toxins, and animals immunized with it 

 do not possess increased resistance to B. diphtherias. 



BACILLUS XEROSIS. In 1884, Kutschert and Neisser * described a 

 bacillus which they had isolated from the eyes of patients suffering from 

 a form of chronic conjunctivitis known as xerosis. This bacillus, which, 



FIG. 108. COLONIES OF BACILLUS HOFFMANNI ON AGAR. 



morphologically, is almost identical with B. diphtherias, they believed 

 to be the etiological factor of the disease. The frequency with which it 

 has been isolated from normal eyes, however, precludes this etiological 

 relationship, and it may safely be regarded as a harmless parasite which 

 may indeed be more abundant in the slightly inflamed than in the normal 

 conjunctiva. 



' Kutschert und Neisser, Deut. med. Woch., xxiv, 1884. 



