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. 



to 8 months, the four central incisors, 



" 10 " four lateral incisors, 



" 16 " four anterior molares, 



" 20 " four cuspidati, 



" 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, 

 central incisors, 

 lateral incisors, 

 anterior bicuspides, 

 posterior bicuspides, 

 cuspidati, 

 second molares, 

 third molares or denies sapientice. 



— Fig. 8 is a side view of a beautiful set of the permanent 

 teeth of both jaws, fitted in their sockets, showing the exact 

 manner in which the surfaces of each set are adjusted to each 



f^m. 



