

CHAPTER XV. 

 BACILLUS DIPHTHERIA. 1 



Introduction. 



Section I. Experimental inoculation, p. 247. 



1. Symptoms and lesions produced in animals susceptible to infection, p. 247. 

 2. Influence of other organisms on the clinical course of the disease, p 249. 

 Section II. Morphology, p. 250. 



1. Microscopical appearance and staining reactions, p. 250. 2. Cultural charac- 

 teristics, p. 253. 

 Section III. Biological properties, p. 254. 



1. Vitality and virulence, p. 254. 2. Bio-chemical reactions, p. 256. 3. Toxin, 

 p. 257. 4. Vaccination, p. 262. 5. Serum therapeutics, p. 265. 6. Agglutination, 

 p. 269. 



Section IV. Detection, isolation and identification of the diphtheria bacillus The 

 clinical diagnosis of diphtheria, p. 269. 



1. Collection of the material p. 270. 2. Methods of examination, p. 270. 3. Sum- 

 mary of diagnostic tests, p. 273. 



Bacillus pseudo-diphthense. 



(Hofmann's bacillus). 



1. Introduction, p. 273. 2. Morphology and staining reactions, p. 273. 3. Cultural 

 characteristics and bio-chemical reactions, p. 274. 4. Virulence and immunity 

 reactions, p. 274. 5. The relation of Hofmann's bacillus to the diphtheria bacillus, 

 p. 274. 



THE diphtheria bacillus was discovered by Klebs but the first complete 

 description of the organism was contributed by Lceffler, while the specific 

 relationship of the bacillus to the disease was established by Roux and Yersin 

 who experimentally produced symptoms of paralysis in animals. 



Distribution of the diphtheria bacillus. 



1. In man. 



The Klebs-Lceffler bacillus is found in the false membranes of faucial, nasal and 

 cutaneous diphtheria, and in croup. Inflammatory conditions of the throat in 

 which no false membrane is formed are also sometimes due to the diphtheria bacillus, 

 and in these cases the true nature of the disease can only be determined by bacterio- 

 logical examination. 



The bacillus is generally localized in the false membrane or on the infected mucous 

 membrane : it does not as a rule invade the tissues : death is the result of a true 



1 The diphtheria bacillus with the pseudo-diphtheria bacillus, the xerosis bacillus and 

 the bacillus of glanders, are by German writers classified together as the Corynebacteria, 

 and known respectively as the C. diphtheria, C. commune, C. conjunctive and C. mallei. 

 The group is characterized by the presence of metachromatic granules and club-shaped 

 swellings at the ends of the organisms, and by the appearance of branched forms in old 

 cultures. 



