356 



VETERIXARV P.\THOLOGY. 



with this disease than other animals, though actinomycosis of 

 sheep, gnats and hogs is occasionally reported. A few cases 

 ha\e also l)een observed in the horse, mule, dog and wild ani- 

 mals. 



Etiology. — A fungus, the Cladothrix actinom^ces or actino- 

 myces bnvis, is the specific cause of actinomycosis. The life his- 

 tor\' of this organism is not known, but it is thought that it 

 passes a part of its life cycle upon some of the grasses. Each 

 matured fungus is ccjmposed of a central ]jod\- 10 to 41) microns 

 in diameter, from wliich the radiating filaments (mycelia) extend 

 outward for a distance of from ■"> to 20 microns, then becoming 

 enlarged, terminate in club-shaped l)odies from 10 to .10 microns 

 in length. Thus the matured fungus has the appearance (jf a 

 rosette and is commonly called the "rav fungus." Detached clubs 

 are capable of reproducing the entire rosettes as described. The 

 fungus can be cultivated in artificial media where it de\-elops 

 a tangled mass of m_\'celia. 



Source. — The Cladothrix actinomyces is probably most fre- 



fikmi 



Fig- 197. — Drawing of ActinomyccH (Ray fungus) in section of tongue. 



