CHAPTER VIII 



DISEASES CAUSED BY FUNGI. 



ACTINOMYCOSIS. 



Symptoms. Lumpy jaw ; wooden tongue; big head. 



§ 226. Characterization. Actinomj'cosis belong.s to 

 the class of affections known as the infectious granulomata. It 

 is a chronic disease determined by the presence of a specific 

 cause — the ray fungus — which by irritation stimulates the for- 

 mation of new growths consisting of round cells, epithelioid 

 cells, giant cells and fibrous tissue. The neoplasms appear as 

 tumors having either a tendency to develop into large and 

 hard masses or to suppurate. It has been suggested that the 

 suppuration was due to a secondary infection by pyogenic 

 bacteria. 



Cattle (genus Bos) are most often attacked. Horses, 

 dogs, pigs, sheep and elephants are slightly susceptible and a 

 few cases have been reported in each. Men are susceptible 

 but this disease is rarely found in the human subject. Other 

 species seem to be immune. 



§ 227. History. The early history of this disease is 

 quite obscure. Prior to the discovery of its specific cause, it 

 was much confused with other diseases resembling it more or 

 less closely in certain gross appearances. It was designated 

 by a variety of names, the more common of which are swelled 

 head, lumpy jaw, big head, fibroma, sarcoma and osteosar- 

 coma. It is popularly known in the United States as " lumpy 

 jaw" and in Europe as "wooden tongue." The popular 

 names were probably suggested by the character of tlie lesions, 

 which differ to a marked degree. It was recognized as a 

 specific disease by Rivolta in 1868, by Perroncito in 1875 and 



