

311 



formed 1-y t he o lontohlasts (o), or dent inal eel: tpatthesamo 



time acquires a coating of enamt-1 (.<?) from tin- enamel in.-iii' 

 (KIII) ; tlien there are continuall -1 <>n the lir>i layers new 



. until the crown of the tooth is completed. I 'nder pressu 

 the latter the enamel-pulp (.sy>) atrophies, ami forms only a thin 

 OOYering to t'io tooth at l.irtli. The papilla ( :/) is converted ii. 

 mass of connective tissue Containing Uood-TOISeli (f) and nerves, and 

 lills the cavity of 

 the tooth as the so- 

 called pulp. The 

 larger the whole 



structure becomes, 



the more it M 

 up the tissue of 

 the gum, which 

 covers the edge of 

 the jaw, and 

 causes it to be- 

 come gradually 

 thinner. Finally, 

 it breaks through 

 the gum si -on aft i r 

 birth, and at the 



s.lllie time , 



oil' from its sur- 

 face the atrophied 

 it mnant of the 

 enamel-or-an. 





Fig. 173. Section through the fundament of the tooth of a young 

 Dog. 



ilveoliiB of the to*'' blootl-veasel ; 



o, odontob!. .<;, enamel ; 



namel-membrane ; , dental M 



The time has 

 now come in which 

 the third hard si di- 

 stance of tin- tooth 

 is formed, the cenfutimi. that env-l-p^ the root. So far as the 

 dentine lias received no coating of enamel, the hounding con- 

 n vti\ eii--i 10 of the dental sac i . after th- emptioa of the 



teeth, to o.-sify and to pro luce a gi-nuim- 'ie with numerous 



SITARPEY'S fibres ; this bony s to the firmer union of 



the root of the tooth with its connective-tissue surround i 



The eruption of tJte teeth ordinarily tak s place with a certain degree 

 of uniformity in the second half of the lirsi year after birth. Fir>t 

 the inner incisors of the lower jaw !>:. ak through in the sixth to the 



