OSSEOUS TUMOURS— OSTEOID TUMOURS. 421 



Vin. — OSSEOUS TUMOURS AND OSTEOPHYTES 



Are very irregular, of a warty stalactic shape, and are common 

 in the neighbourhood of joints where the articular surface is 

 affected with caries, and sometimes surround the tendons of a 

 limb when no joint disease is present. — (See Photo-lithograph, 

 Plate I., Pig. 4.) 



They result from the ossification of an exudate which has 

 been formed in consequence of some cause of intlammation. 

 Osseous tumours are of a more compact structure than osteo- 

 phytes, and grow more from the compact structure of the bone 

 itself. Cases of great lameness sometimes occur from these new 

 formations becoming inflamed from accidental causes, and I 

 have seen necrosis of them produce sloughing of the skin, and 

 the formation of sinuses. 



IX. — OSTEOID TUMOURS — OSTEOAIA. 



(See Photo-lithograph, Plate I., Fig. 9.) 



These are tumours of irregularly protuberant surface, affect- 

 ing both the upper and lower jaws of horned cattle. They are 

 generally of a slow, but sometimes of a rapid growth, and 

 when so, they possess some malignity (see Ostea-Sarcoma.) They 

 consist of a cancellous bony tissue, forming trabeculae, which sur- 

 round spaces filled with a greyish white, vascular, fibrous material, 

 in which a varying quantity of cells and nuclei are imbedded. 



These tumours may vary in their density, from the presence 

 of more or less bony structure in their formation. 



If not depending upon the presence of the actinomyces, or 

 upon the irritation of the tubercular bacillus, when these 

 tumours would be more properly classed amongst "inflam- 

 matory growths," the osteoma, benign in their nature, are very 

 rarely met with in practice. The tumours of the maxillae of 

 cattle are generally evidences of actinomycosis, now said to be 

 curable by iodide of potassium given internally. 



The only treatment that can be recommended is the removal 

 of the tumour at its very earliest stage, and before it has 

 attained any size. If it be of any magnitude no treatment 

 should be attempted, but the animal ought to be fed for 

 slaughter, if not already fit. These tumours do not seem to cause 

 much pain or inconvenience for a long time, and hence the 

 animal will feed well enough. 



