PROF. TOMES'S THEORY. 37 



tubules, continued from or communicating with the 

 radiated cells. These tubules, and the more parallel 

 ones which traverse the thickness of the cement in 

 many mammalia, are the remains of linear series of 

 the minute granules of the blastema. * * * 



" The general form of the dental matrix and its rela- 

 tion with its calcified product, bear a close analogy 

 with those of the formative organ of hairs, bristles, and 

 other productions of the epidermal system. In these 

 the papilla, or pulp, is developed from the external 

 skin; in the teeth, from the mucous membrane, or 

 internal skin." * * * * 



Prof. Charles S. Tomes, among dentists a recognized 

 authority, differs with Messrs. Hunter and Owen as 

 to the pulp's secretive office, claiming that a tooth is 

 formed by a partial metamorphosis of its pulp. He 

 says ("Manual of Dental Anatomy, Human and Com- 

 parative," pp. 104-5-6) : 



" Prior to the beginning of any calcification, there 

 is always a special disposition of the soft tissues at the 

 spot where a tooth is destined to be formed, and the 

 name of ' tooth-germ ' is given to those portions of the 

 soft tissue which are thus specially arranged. All, or 

 a part only, of the soft structures making up a tooth- 

 germ become converted into the dental tissue by a 

 deposition of salts of lime within their own substance, 

 so that an actual conversion of at least some portions 

 of the germ into tooth takes place. The tooth is not 

 secreted or excreted by the germ, but an actual meta- 

 morphosis of the latter takes place. 



" The principal tissues, namely, dentine, enamel, and 

 cement, are formed from different parts of the tooth- 

 germ; hence we are accustomed to speak of the enamel- 



