116 DEVELOPMENT OF THE TEETH. 



wasting of the latter set, a process of which we find the analogue 

 in the development of many parts of the foetus. 

 Below is a tabular view of the appearance of the temporary- 

 teeth, and also of the periods at which they are changed for the 

 permanent. 



It is to be taken, however, as a general rule liable to 

 continual exceptions, not only in regard to the time, but also 

 as to the regular order of appearance. As a general rule, the 

 teeth of the lower jaw appear first, then the corresponding 

 teeth of the upper. 



Deciduous Teeth. 



From 5 to 8 months, the four central incisors, 



" 7 " 10 " four lateral incisors, 



" 12 " 16 " four anterior rnolares, 



"14 " 20 " four cuspidati, 



" 18 " 36 " four posterior molares. 



Permanent Teeth. 



The first permanent molares usually pierce the gum before 

 the fall of the central incisors, and their appearance indicates the 

 approaching change. 



The following are about the medium periods at which they 

 are cut, but there is a great degree of variation in this respect. 

 Those of the lower are here indicated, and they most commonly 

 precede the upper by about two or three months. 



About 6| years, the anterior molares, 



" 7 " central incisors, 



" 8 " lateral incisors, 



" 9 " anterior bicuspides, 



" 10 " posterior bicuspides, 



11 to 12 " cuspidati, 



12 " 13 " second molares, 



17 " 19 " third molares or denies sapientice. 



Fig. 8 *is a side view of a beautiful s of the permanent 

 teeth of both jaws, fitted in their socke' showing the exact 

 manner in which the surfaces of ea^i set are adjusted to each 



