Pathogenesis 



717 



Inoculation has, so far, failed to reproduce the disease either in 

 man or in the lower animals. 



Pathogenesis. — The bacillus is said to be pathogenic for man only, 

 producing granulomatous formations of the skin and mucous 

 membranes of the anterior and posterior nares. These vary in 



Fig. 294.^BaciIlus rhinosderomatis. Pure culture on glycerin agar-agar. Mag- 

 nified 1000 diameters (Migula). 



structure according to age. The young nodes consist of a loose 

 fibrillar tissue composed of lymphocytes, fibroblasts, and fibers. 

 Some of the cells are large and have a clear cytoplasm and are 

 known as the cells of Mikulicz. In and between them the bacilli 

 are found in considerable numbers. The older lesions consist of a 

 firm sclerotic cicatricial tissue. 



