122 DEKTAL CYSTS. 



" In common with others, I have studied several of 

 these dental tumors. They may spring from several 

 of the bones of the head, but especially from the region 

 of the petrous temporal bone. They may project to- 

 ward the interior of the cranium, but they more fre- 

 quently project outwardly. They may be strongly 

 implanted in the bone, or get separated; then they 

 are maintained in their situation by the soft textures 

 around. Their development is not more extraordinary 

 than that of other osseous growths that spring from 

 the cranial or maxillary bones; and their tooth-formed 

 structure (teeth in the region of teeth), is not more 

 wonderful than bony tumors in other parts of the sys- 

 tem, whether connected or not with the skeleton/' 



Prof. William Sewell, President of the British Vet- 

 erinary Medical Association, at the meeting of that 

 body on May 15, 1838, advanced an interesting theory 

 of the growth of abnormal teeth. It may be true, for 

 after the teeth have attained their full growth, it is 

 reasonable that the dental arteries are less active. But 

 as the teeth continue to grow throughout life, a fact 

 Prof. Sewell does not mention, it is not so reasonable 

 that they even "in a manner cease" to act. The pro- 

 fessor's remarks are thus reported ("Veterinarian/' 

 1838, "Proceedings Vet. Med. Ass.," p. 199): 



" The President begged leave to direct the attention 

 of the meeting to a horse's tooth that had been pre- 

 sented to him. It was a fine specimen of the anomaly 

 occasionally observed in the dental system of the horse 

 the production of teeth in other places than the 

 alveolar cavities, after the natural teeth had been per- 

 fected. The situations which Nature in her wander- 

 ings selected were occasionally very singular. He had 



