Bacilli Resembling the Diphtheria Bacillus 493 



variola pustules, and it has also at times been isolated from 

 the internal organs, as in the cases of Egyptian dysentery 

 studied by Kruse and Pasquale.* Ohlmacher has also 

 found it with other bacteria in pneumonia; Babes, in 

 gangrene of the lung; and Howard,f in a case of ulcerative 

 endocarditis not succeeding diphtheria. 



While various authors have endeavored to point out 

 morphologic and cultural differences by which the diphtheria 

 and pseudo-diphtheria bacilli can be differentiated, it must 

 be admitted that the variations of the latter organism are 

 so numerous that all rules fail. The only criterion for 

 specific differentiation is the ability of the true diphtheria 

 bacillus to form toxin, which the pseudo -diphtheria bacillus 

 entirely lacks. The inoculation of the pseudo-diphtheria 

 bacillus into animals is followed by no pathologic changes. 



G. F. PetriJ found no substances in filtrates of cultures of 

 Hoffmann's bacillus capable of neutralizing diphtheria anti- 

 toxin; he also found that horses immunized with large 

 quantities of filtrates of the Hoffmann bacillus did not pro- 

 duce any antitoxin to diphtheria toxin. Eleven different 

 cultures were studied and the results are very important. 



Knapp shows that there is a chemico-biological difference 

 between the true and pseudo-diphtheria bacilli, in that the 

 pseudo-bacillus ferments saccharose, which the true bacillus 

 does not, and that the true bacillus ferments dextrin, which 

 the pseudo-bacillus does not. 



Park || carefully studied this subject, and found that all 

 bacilli with the typical morphology of the diphtheria bacillus, 

 found in the human throat, are virulent Klebs-Loffler 

 bacilli, while forms found in the throat closely resembling 

 them, but more uniform in size and shape, shorter in length, 

 and of more homogeneous staining properties with Loffler's 

 alkaline methylene-blue solution, can with reasonable safety 

 be regarded as pseudo-diphtheria bacilli, especially if it be 

 found that they produce an alkaline rather than an acid 

 reaction by their growth in bouillon. The pseudo-diph- 

 theria bacilli were found in about i per cent, of throats ex- 



* " Zeitschrift fur Hygiene," xvi, 1. 

 t"Bull. of the Johns Hopkins Hospital," 1893, 30. 

 t" Jour, of Hygiene," vol. v, No. 2, April, 1905, p. 134. 

 "Jour, of Med. Research," xi, 1904, p. 475. 



|| "Scientific Bulletin No. 1," Health Department, city of New 

 York, 1895. 



