508 



PRINCIPLES OF VETERINARY SURGERY 



rich in actinomyces. The underlying periosteum is attacked. 

 When the parasite is deeply implanted, when it has attacked 

 the jaw by way of the mouth, it produces an irritation that 

 acts chiefly on the maxilla. Nests are formed in the can- 

 cellated tissue of the bone. It swells the osseous plates, 

 separates them, weakens the compact tissue and raises a 

 tuberous mass that becomes soft and often ulcerated on the 

 surface, either in the buccal cavity or externally. When lo- 

 cated in the superior maxilla, even the nasal cavities and 

 their appendages become involved. 



There is a manifest deformity of the jaw, consisting of 



Fig. 54. 

 Actinomycostic Tumor of the Inferior Maxilla, Showing Ulcerations 

 and Granulations. 



an apparent separation of the osseous plates. When the 

 lesion is much developed the molar teeth loosen and fall 

 out. It appears as if an "osseous sponge" had been inter- 

 posed between the sound bone plates. The tissues are 

 corroded and hollowed out, with irregular cavities united 

 by bridges of bone. In the recesses of these cavities the 

 bone tissue is hard, but perforated with an indefinite number 

 of hores that give the appearance of a sponge. The swollen 

 osseous mass contains, here and there, very thin translucent 

 lamellae that resemble fine lace. 



At the other limits of the lesicy.1 the periosteum has lost 

 its toughness and is pierced with innumerable openings. 



