PATHOLOGIC CHANGES 407 



the mouth. In the interior of the granulation tissue which has been 

 invaded and partly replaced the osseous bone substance is still present 

 in the shape of a honeycombed network with wide open spaces. As 

 the granulation tissue invades the maxillary bone more and more it 

 often loosens teeth and lifts them out of their alveolar position. The 

 gums also become involved and exhibit larger or smaller granulomatous 

 masses, which may ulcerate extensively. The condition of the maxil- 

 lary bones of cattle which have been extensively invaded by actino- 

 mycosis generally resembles that of bones which have become the 

 seat of an osteosarcoma, and hence the disease was formerly mistaken 

 for such a bone tumor. Actinomycosis starting from the periosteum 

 of the maxillary bones generally leads to much denser, more solid, 

 more fibrous tumor masses. In the mouth cavity actinomycotic masses 

 frequently have the shape of mushrooms and cauliflower excrescences. 



FIG. 162 



Actinomycosis of the inferior maxillary bone of cattle. 



Primary actinomycosis of the esophagus, the lower gastro-intestinal 

 tract and the respiratory tract in cattle, is rare; the liver, however, is 

 frequently full of actinomycotic abscesses in advanced cases. 



The actinomycotic tumor of the head of cattle after having grown 

 to a certain size frequently leads to superficial ulcerations. It then 

 presents an uneven ulcerated surface from which granulomatous 

 cauliflower masses may protrude. Such ulcerations discharge a 

 yellowish, creamy, or very tenacious, gluey pus. In this pus the 

 typical grayish-yellow or brownish granules of the ray fungus are 

 generally found. 



Subcutaneous actinomycosis in cattle is not always confined to the 

 head, but is also found in the back, legs, and thighs. In swine 

 actinomycosis frequently finds entrance through the tonsils or through 

 the nipples, the latter being injured when the animals are kept in 



