CHAPTER V. 



DISEASES CAUSED BY FUNGI. 



ACTINOMYCOSIS. 



Synomyms. Lumpy jaw : Wooden tongue ; Big head. 



§ i6o. Characterization. Actinomycosis belongs to the 

 class of affections known as the infectious granuloniata. 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. Men are 

 susceptible but the disease is rarely found in the human sub- 

 ject. Horses, dogs, pigs, sheep and elephants are slightly 

 susceptible and a few cases have been reported in each. Other 

 species seem to be immune. 



S i6i. History. The early history of this disease is quite 

 obscure. Prior to the disco\'ery of its specific cause it was 

 much confused with other diseases resembling it more or less 

 closeh' in certain gross appearance. It was designated by a 

 variety of names, the more common of which are swelled head, 

 lumpy jaw, big head, fibroma, sarcoma and osteosarcoma. It 

 is popularlj' known in the United vStates as "lumpy jaw" and 

 in Europe as "wooden tongue." The popular names were 

 probabh' suggested by the character of the lesions which differ 

 to a marked degree. It was recognized as a specific disease by 

 Rivolta in 1868, by Perroncito in 1875 and by Bollinger in 

 1877. The ray fungus was undoubtedl}' observed prior to this 



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