206 



THE TEETH AS INDICATORS OF AGE. 



color, and know not what conclusion to draw when 

 they see both discoloration and irregularity." The 

 marks in the dividers are much reduced in size, but 

 those of the corner teeth are large and distinct. 



At seven years the marks disappear from the divider 

 incisors, and at eight from the corner teeth. 



Monsieur Girard thus describes the changes in shape 

 of the incisors, referring also to the disappearance of 

 the marks in the upper teeth: 



"At nine the central incisors become rounded, the 

 dividers oval, and the corner teeth narrower. The cen- 

 tral enamel (mark) diminishes and 

 approaches the posterior edge. 



"At ten the dividers are rounder, 

 and the central enamel is very near 

 the posterior edge and rounded; at 

 eleven they have become rounded, and 

 the enamel has disappeared. 



"At twelve the corner teeth are 

 rounded. The yellow band is larger, 

 and occupies the center of the wear- 

 ing surface. 



"At thirteen all the lower incisors 

 are rounder; the sides of the centrals 

 are becoming longer. The central 

 enamel remains in the upper corner 

 teeth, but is round and approaching 

 the posterior edge. 



"At fourteen the lower central in- 

 cisors have a triangular appearance; 

 the dividers are becoming long at their sides. 



"At fifteen the central incisors are triangular, and 

 the dividers are becoming so. 



The forms successive- 

 ly assumed by the dental 

 table of an incisor in con- 

 sequence of friction. A. 

 Chauveau. 



