30 Comparative Studies 



Olmacher (32) found the pseudo-diphtheria bacilli in a 

 case of pneumonia, accompanied with purulent meningitis. 



Cobbett and Phillips (33) state that u the frequent occur- 

 rence in the mouths of healthy persons of organisms which 

 more or less resemble the diphtheria bacillus makes it 

 desirable that we should have some test which would 

 enable us to distinguish them from the latter. A satis- 

 factory test of this kind has indeed not yet been found. 

 We know of no other way of distinguishing the non- 

 virulent acid-producing bacillus but by the injection of 

 animals. On the other hand, the cultivation of a suspected 

 diphtheria bacillus in an alkaline glucose broth gives us a 

 ready means of excluding the other simulator of the diph- 

 theria bacillus. This non-virulent organism, which is 

 characterized by its inability to produce an acid reaction in 

 such a medium, is found in the mouths of persons suspected 

 of having diphtheria at least as frequently as is the non- 

 virulent acid producer. We therefore venture to recom- 

 mend that this simple test be applied to any organism 

 suspected of being the lyoffler bacillus." 



Fraenkel (34) investigated the value of Neisser's special 

 method of differential staining, and says that when the 

 conditions laid down by Neisser are strictly observed in 

 every particular this method affords a highly satisfactory 

 diagnostic method. He found three cultures which gave 

 a distinct, positive result with this special staining, and 

 also rendered the culture media acid, and in other respects 

 resembled the true diphtheria bacilli, except that they 

 were non-pathogenic for guinea pigs, in very large doses. 

 Two of these cultures were derived from cases of typical 

 diphtheria, and he is undecided whether these are non- 

 virulent Loffler bacilli or not. 



Zupink (35) in a comparative investigation of some 

 pseudo-diphtheria bacilli found the Gram method of stain- 

 ing was of some value in differentiating between these 

 organisms and the LofHer bacillus. He divides the organ- 



