VE TRRINAR T DENTAL S URGER 2 '. 129 



illustrates that substances foreign to their position do 

 not always cause trouble simply because they exist. 



In view of these facts it appears as though teeth 

 developed in other parts of the body than the mouth 

 do not cause a fistulous opening because they are 

 foreign to their location, but that they follow the 

 same law of development and after a certain period, 

 in their effort to reach the surface, destroy the soft 

 tissues which impede their exit, the same as any 

 other teeth. I have seen a discharge take place in a 

 number of instances over the region of the canine 

 teeth when about to make their exit. 



Why these teeth should develop at all outside of 

 the mouth is a mystery which as yet needs a satis- 

 factory solution, especially when located in the lum- 

 bar region, the ovaries and testicles. Their appear- 

 ance in the sinuses can be traced to a definite source 

 and I think is satisfactorily explained by Professor 

 Williams, who says: * " To understand the process 

 by which these tumors are formed, it is necessary to 

 remember that the teeth of all animals belong to and 

 arise from the membranous portion of the digestive 

 canal and that at a very early period of foetal life pro- 

 vision is made for the development of the perma- 

 nent teeth as well as the temporary. This provision 

 according to Goodsir, who devoted much of his 

 attention to the subject is as follows : ' As early as 



* Principles and Practice of Veterinary Surgery, page 430. 



