ANIMAL DENTISTRY. 



217 



They begin by the appearance of one or more malignant look- 

 ing foci, and gradually invade more and more widely into 

 the surrounding tissues. They usually perforate the bony 

 palate and establish a free communication between the 

 mouth and nasal cavities. In the old cases that are allowed 

 to survive, the process may extend backward to the ethmoid 

 and sphenoid bones and from the point of origin through the 

 fauces into the pharynx. They become complicated with an 

 offensive catarrh of the nasal mucosa and with more or less 



Fig. 147. 

 The Effect of a Carcinoma Beginning at the Palate of a Young Horse. 



disturbance to the eye. One case coming to our notice ex- 

 cavated a large opening externally through the malar and 

 lachrymal bones and totally destroyed the globe of the eye 

 and its appendages. The condition is of course incurable and 

 is met by recommending the killing of the patient. (Fig 



I47-) 



SARCOMATA OF THE MOUTH. 



Sarcomatous growths in the palate of the horse are of 

 frequent occurrence. They begin in the periosteum of the 



