ERUPTION OF THE PERMANENT INCISORS. 



167 



Tliree Yecu's, Three Months. — Between three years and 

 tliree and one-half years the second intermediate have repladed 

 tlie milk-teeth. (Fig. 164.) 



Fig. IW. 

 Three years, six months, a, external face. 6, internal face. 



In this month the second intermediate teeth have reached 

 the level of the incisive arch and their enamel has commenced 

 to be used. 



Four Years. — Between three years and nine months and 

 four years and six months the corner teeth are completely 

 through the gums and the mouth is complete. (Fig. 165.) 



