BACTERIUM DIPHTHERIA. 389 



teeth, the morphology of which is so like that of the 

 bacillus of diphtheria that they might easily be mistaken 

 for that organism if subjected to only the usual method 

 of microscopic examination ; and again, the genuine 

 diphtheria organism is sometimes found in the mouth- 

 cavities of healthy persons in attendance upon diph- 

 theria cases, such persons being at the time insusceptible 

 to the pathogenic activities of the organism. In the 

 vast majority of instances, however, where the clinical 

 condition of the patient justifies a suspicion of diph- 

 theria, a microscopic examination alone of the deposit 

 in the throat will serve to confirm or contradict this 

 opinion, and such examinations very frequently reveal 

 the diphtheritic nature, etiologically speaking, of mild 

 conditions of the throat which are not associated with 

 grave constitutional manifestations. 



BACTERIUM DIPHTHERIA (LOFFLER), MIGULA, 1900. 



Synonyms: Bacillus diphtherias, Loffler, 1884; Klebs-Loffler bacil- 

 lus ; Corynebacterium diphtherias, Lehmann and Neumann. 1896. 



Bacterium diphtherse, discovered microscopically by 

 Klebs, and isolated in pure culture and proved to 

 stand in causal relation to diphtheria by Loffler, can 

 readily be identified by its cultural peculiarities and 

 by its pathogenic activity when introduced into tissues 

 of susceptible animals. In guinea-pigs and kittens the 

 results of its growth are histologically identical with 

 those found in the bodies of human beings who have 

 died of diphtheria. 



When studied in pure culture its morphological and 

 cultural peculiarities are as follows : 



MORPHOLOGY. As obtained directly from the diph- 

 theritic deposit in the throat of an individual sick of 

 the disease, it is sometimes comparatively regular in 



