HUMAN DENTITION. 457 



manifested at a period when the subjects of comparison are far from 

 having attained the pre-ordained term of deviation from the common 

 primordial type, and antecedent to those changes in the dental system 

 itself, which more broadly characterise the species, and, in the Orang 

 and Chimpanzee, proceed further to mark the different sexes. 



175. Succession. — The primary development of the matrices of 

 both the deciduous and permanent Human teeth has been described 

 in the ' Introduction'. Calcification of the permanent series com- 

 mences first in the pulp of the first true molar, and very soon 

 after, if not simultaneously in that of the anterior incisor, about 

 five or six months after birth. The first true molar (PI. 121, m 1) 

 comes into place and use between the sixth and seventh year(l) : 

 the first permanent incisor (ib. i 1) between six years and a half, 

 and eight years : the calcification of the pulps of the lateral incisor 

 (i 2) and canine, (c) commences about eight or nine months after 

 birth, and they cut the gum, the canine quickly following the in- 

 cisor, between the seventh and ninth years. Calcification of the 

 first premolar (bicuspis, p 1) begins at, or soon after, the second 

 year, that of the second about a year later, and both premolars 

 have displaced the deciduous molars, and come into use between 

 the eighth and tenth years. The pulp of the second molar (m 2) 

 begins to be calcified about the fifth or sixth year, and it cuts 

 the gum from about the twelfth year to the fourteenth year ; but 

 always later than the permanent canines and premolars. The third 

 molar or dens sapienticB, begins to be calcified about the twelfth 

 year, and usually comes into place at or after the twentieth 

 year. 



Both earlier and later periods of the development of the per- 

 manent teeth have been observed and recorded ; but such varieties 

 rarely affect the general order of succession. I have described this 

 order as it occurs in the lower jaw, the teeth of which usually 

 appear earlier than the corresponding ones above. It will be seen, 

 therefore, that the Human subject diflTers from the Chimpanzee and 

 Orang in the order of progression of the permanent teeth. John 

 Hunter, after indicating the first incisor and the first molar as 



(1) Hunter says it cuts the gum about the twelfth year of age ; but this must be a rare 

 exception, if it is not a mistake. See " Natural History of the Human Teeth," 4to. p. 84. 



