ETIOLOGY 



301 



Mississippi \'alley and lu the South-west it seems to be more 

 prevalent than it is east of the Alleghany Mountains. 



§ 229. Etiology. Actinomycosis is produced by a 

 fungus, Cladothrix acfiiioii/ya's, commonly known as the "ray 

 fungus." * The disease is the result of its multiplying in the 

 tissues and not from the elaboration of a toxin. Undoubtedly 



S.:p 





wm^"^ 



fL-.Z2& 





Fig. 69. A rosette of the ray fungus together with different forms of 



tlie single club ends. <^ 2^00. [After Crook shank) . 



the bacteria often associated with the fungus in suppurating 

 lesions are of some significance. Wright states that he believes 

 they play an important part in the extension of the disease. 

 The fungus appears as minute, yellowish granules in the 

 lesions. When examined microscopically, these granules are 



*The cladothrix is placed among the higher bacteria. There are 

 many varieties of the actinomyces. Until they are better understood it 

 seems better to group them with the fungi. 



