THE NOEMAL CONJUNCTIVA 



81 



presence as an established fact, in some cases after their authors had made special 

 control tests (Flugge Giinther, Beck in Kolle-Wassermann, Lehmann-Neumann, 

 and others). The fact is now generally accepted in ophthalmic circles. Again and 

 again, however, the opinion is brought forward that this organism has a definite 

 pathogenicity. Deyl and his pupil Hala considered it as the cause of chalazion ; 

 Peters considered it as a contributing cause in many benign membrane formations 

 after injury to the conjunctiva. It was brought forward in cases of wound in- 

 fection. Eandolph and Del Monte considered that it took part in many cases of 

 conjunctivitis. Gifford found it in lid abscesses. I will return to this question 

 later on. 



A complete description of this bacillus will not be given now, but' 

 will be found with that of the diphtheria bacillus (p. 190). 



FIG. 4. VARIATION IN SIZE AND SHAPE OF THE BACILLUS XEROSIS IN 



CULTURE. 



1-6, Loffler's methylene-blue stain ; 7-9, M. Neisser's pole-staining, 9 to 16 hours' culture 

 on blood-serum ; 7, virulent diphtheria bacilli, typical pole-staining ; 8, Xerosis quite 

 unstained ; 9, Xerosis incomplete staining. 



The sketches on the coloured plates, and in Fig. 4, which is by 

 Heinersdorff, should be carefully noticed at this point. 



The relation of this so-called Bacillus xerosis to the pathogenic 

 Loffler's Bacillus diphtheria will now be shortly discussed. Some 

 observers (Eoux, Schanz, Peters, Hala, Behring, and others) consider 

 that all thesa bacilli are identical with the diphtheria bacillus, and 

 that the descriptive names ' pseudodiphtheria bacillus,' and ' xerose 

 bacillus,' should not be used ; we have either poisonous or harmless 

 Loffler's (i.e., diphtheria) bacilli which merge into each other. The 

 harmless constant inhabitants of the normal conjunctiva can, under 

 favourable circumstances, develop into virulent diphtheria bacilli. 



