Mode of Infection 



783 



but there is little evidence that the introduced micro-organisms have 

 multiplied. 



Mode of Infection.— The manner by which the organism enters 

 the body is not known. There are some who believe that the organ- 

 ism occurs in nature as a saprophyte, or as an epiphyte upon the hulls 

 of certam grains, especially barley. Woodhead has reported a case 



-Section of liver from a case of actinomycosis in man 

 (Crookshank). 



where a primary mediastinal actinomycosis in the 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 human 

 medicine, and do not always occur in those brought in contact with 



