DEVELOPMENT OF THE TEETH. 



1565 



and so does the wisdom-tooth much later. The inferior second molar is formed 

 almost in the angle between the body and ramus. The inferior wisdom-tooth, before 

 it cuts the gum, faces forward, inward, and slightly upward. To the table from 



FIG. 1324. 



Permanent molars 



Permanent molar 



Permanent canine 

 Bicuspids 



Permanent incisors 



Temporary canine 

 Temporary molars 



Permanent incisors 

 Temporary canine 



Permanent canine 

 Bicuspids 



Jaws of child of ten years, showing partially erupted permanent teeth with temporary canines and molars still in 



place. 



Rotch we add one from Livy, 1 who made observations on several thousand children 

 of English and Irish operatives. 



TABLE OF ERUPTION OF PERMANENT TEETH. 2 



Years. Groups. 



6 Four first molars. 



7 Four middle incisors. 



8 Four lateral incisors. 



9 Four first bicuspids. 



Years. Groups. 



10 Four second bicuspids. 



11 Four canines. 



12 Four second molars. 

 17 to 25 Four wisdom-teeth. 



TABLES SHOWING TIME OF ERUPTION OF PERMANENT TEETH. 3 



BOYS. 



Ages. 9 10 ii 



Lateral incisors .... 2 42 9 



First bicuspids i 76 12 



Second bicuspids .... . . 59 36 



Canines . . . 



Second molars 



1 British Medical Journal, 1885. 



i8 28 25 



5 42 67 275 184 78 12 663 



16 Total. 



59 

 90 

 101 

 79 



2 From Rotch. 



3 From Livy. 



