IX. 

 BACTERIA IN DIPHTHERIA. 



DIPHTHERIA is generally recognized by physicians as a specific 

 infectious disease, and, owing to its wide prevalence and fatal char- 

 acter, a precise knowledge of its etiology is of the greatest import- 

 ance. Until, as a result of recent researches, this was determined, 

 pathologists were in doubt as to whether diphtheria should be con- 

 sidered as primarily a local infection, or whether the local manifesta- 

 tions were secondary to a general systemic infection. But this question 

 appears now to be definitely settled in favor of the former view. We 

 have to-day a very precise knowledge of the specific infecting agent, 

 and have evidence that it produces during its growth a very potent 

 toxic substance, the absorption of which from the seat of local infec- 

 tion accounts in a satisfactory manner for the general symptoms of 

 the disease, which are due to toxaemia and not to an invasion of the 

 blood and tissues by the pathogenic microorganism producing it. 



Numerous researches by competent bacteriologists have failed to 

 demonstrate the presence of bacteria in the blood of patients suffer- 

 ing from diphtheria, but a variety of microorganisms have been ob- 

 tained in cultures from diphtheritic pseudo-membranes, and may be 

 demonstrated by the microscopical examination of stained prepara- 

 tions. Among these are the well-known pus organisms, and espe- 

 cially the Streptococcus pyogenes, which appears to be very commonly 

 present, and is perhaps the active agent in the production of certain 

 forms of pseudo-diphtheria. But the malignant, specific diphtheria, 

 so well known in this country and in Europe, has been demonstrated 

 by the recent researches of bacteriologists to be due to a bacillus first 

 recognized by Klebs in stained preparations of diphtheritic false 

 membranes (1883), and cultivated and described by Loffler in 1884. 

 In his first publication Loffler did not claim to have fully demon- 

 strated the etiological relation of this bacillus, but this appears to be 

 fully established by subsequent researches. 



In his first research Loftier studied twenty-five cases, and in the 

 greater number of them found in stained preparations the bacil- 

 lus previously described by Klebs. From six of these cases he 



