DENTITION. 



Later still, four molars issue from the gum in each jaw, two at 

 each side, occupying the first two of the three vacant places 

 marked " in fig. 17, and at a still more advanced age, two other 

 molars issue from each jaw, filling the last vacant place marked 

 " in the fig. 17. 



Thus, a set of sixteen permanent teeth is established in each 

 jaw (fig. 18). The last four molars, which emerge at a period of 

 Fig. 18. 



life much later than me others, have been for that reason vulgarly 

 called wisdom teeth. 



40. The periods of the successive emergence of the permanent 

 teeth are, according to Cartwright, as follows : 



AOJE. 



Middle incisors of lower jaw (i 1 ), and first 1 c *_ 7 



molars (it 1 ) J * 



Middle incisors of upper jaw 

 Lateral incisors (i 2 ) . 

 First bicuspids (B 1 ) 

 Canines (c) 

 Second bicuspids (B 2 ) 



Second molars (M ! ) 



Third molars (M S ) (wisdom teeth) 



6to 8 

 7to 9 



8 to 10 



9 to 12 

 10 to 12 

 12 to 14 

 17 to 25 



41. The mean height of man is about 5 feet' 6 inches, but is sub- 

 ject to great variation, not only in the case of individual compared 

 with individual, but nation with nation, and race with race. 

 Some of the savage tribes of Patagonia, and the inhabitants of the 

 Navigator and Caribbean islands, are remarkable for their elevated 

 stature, their average height varying from 6 feet to 6 feet 3 inches. 



75 



