656 



PRINCIPLES OF VETERINARY SURGERY 



Macerated fragments very clearly give an idea of the na- 

 ture of these alterations and their initial seat. The changes 

 are chiefly manifested on the superior maxillary and nasal 

 bones. The other bones of the head, with the exception of 

 the inferior maxilla, remain normal. The diseased part is 

 constituted of osseous interrupted layers, excavated with fur- 

 rows which in life are filled up with fibrous tissue and layers 

 of cartilage, a vestige of which still remains. So far as the 

 appearance is concerned the diseased portion may appropri- 



Fig. 113. 



Transerve Section Behind the Snout of a Hog Affected with the Disease. A 



Tumor Containing a Dental Follicle is Shown on Each Side of the 



Nasal Fossae. 



ately be compared to a sponge. It appears as if a sponge had 

 been pasted on each side of the septum nasi in front of the 

 orbital ridge. The swelling of the bones, which might be de- 

 scribed as "blown," causes an almost complete obliteration 

 of the nasal cavities. (Fig. 114). The inferior maxillary eii- 

 hibits analogous, but less pronounced alterations. The les- 

 ions of the joints attack different portions of the articula- 

 tions, the periarticular tissues, the synovial membranes, the 

 synovia and the articular cartilage. 



I. The Periarticular Tissues. — The muscles surround- 



