CHAPTER XXIV 



DIPHTHERIA GROUP 



Two organisms will be considered under this heading, the 

 Bacillus diphtheria and B. pseudodiphthericus. The former is of 

 importance in human medicine as the cause of the disease diph- 

 theria, and to the veterinarian, because of the use of horses and 

 other animals in the manufacture of antitoxin, and because of the 

 use that has been made of the toxin in the development of the 

 theories of immunity. The B. pseudodiphihericus is important 

 because of its resemblance to the diphtheria bacillus. 



The characters which particularly differentiate this group are 

 the polar or banded staining of the organisms (presence of meta- 

 chromatic granules) and the production of the characteristic 

 toxin by the diphtheria bacillus. 



The term diphtheria is used in a pathologic sense to denote a 

 type of inflammation characterized by more or less extensive 

 necrosis, and the formation of false membranes of fibrin, which are 

 rather intimately joined to the tissue which produces them. 

 Many organisms can bring about diphtheritic inflammation in the 

 tissues of man and animals. These organisms belong to such 

 varied genera as Streptococcus, Bacillus, and Actinomyces; a 

 pathologic grouping w^ould, therefore, bring together unrelated 

 forms, hence the inclusion of but the one organism under this 

 group. By diphtheria is meant the specific disease of man caused 

 by the Bacillus diphtheria, and diseases of animals resembling it 

 clinically, as fowl diphtheria, are not to be confused with it. 



Bacillus diphtherias 



Synonyms. Klebs-Loffler bacillus; Bacterium diphtheria; Cor- 

 ynebacterium diphtheria; Mycobacterium diphtheria. 



Disease Produced. Diphtheria in man, rarely in some animals. 

 Klebs, in 1883, described an organism present in the false mem- 



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