Pathogenesis 



437 



it may be by direct inoculation with infectious pus, but 

 there is some reason to believe that the organism occurs in 

 nature as a saprophyte, or as an epiphyte upon the hulls 

 of certain grains, especially barley. Woodhead has recorded 

 a case where a primary mediastinal actinomycosis in the 



Fig. 131. Section of liver from a case of actinomycosis in man 

 (Crookshank). 



human subject was apparently traced to perforation of the 

 posterior pharyngeal wall by a barley spikelet accidentally 

 swallowed by the patient. 



Cases of actinomycosis are fortunately somewhat rare in 



