ERUPTION OF THE PERMANENT TEETH 135 



end of eruption as he found them in the French may be com- 

 pared with my records of the Ann Arbor children. 



It is to be seen that the French children are earlier than the 

 children of Ann Arbor both in the beginning of eruption and in 

 the end of the eruption of the teeth, except in the beginning of 

 eruption of the lower median incisors and upper canines, where- 

 fore it is evident that the French at any age are more mature in 

 the eruption of the teeth than the children of Ann Arbor. 



Cherot believes there are four periods of acceleration in the 

 eruption of the permanent teeth, from six to eight and a half years 

 when some teeth are erupting all the time; from 10 to 11 years; 

 at 12 years; and about 20.5 years during the eruption of the third 

 molars. The periods of 10 to 11 and at 12 should be combined 

 because they run together, thus leaving three periods, which have 

 been associated by others with the eruption of the three series 

 of molar teeth. The periods of dentition given by Cherot would 

 then correspond to the periods of acceleration given on page 127. 



Hrdlicka (30, 31) has published the only detailed data of the 

 examination of children's teeth that I have been able to find in the 

 literature. He examined the teeth of the Apache and Pima 

 Indians of North America, and from his records he concludes 

 that the teeth of the Indians appear at about the same ages as 

 the teeth of the whites, with the exception of the canines and 

 second molars which apparently erupt earlier in the Indians than 

 in the whites. I have calculated the beginning of eruption and 

 the end of eruption of the teeth in the Indians, which is based 

 on the stature rather than the age, because the age of the Indians 

 was not obtained by Hrdlicka. The age is calculated from the 

 stature by Hrdlicka, and he remarks that it is doubtless unperfect. 



The order of eruption is similar to that of the Europeans or 

 white peoples, and different from that of the Filipinos, because in 

 the latter the canines erupt before the premolars, whereas in the 

 others the canines erupt at the time of the eruption of the pre- 

 molars, or as noted above: the lower canines erupt between the 

 eruption of the upper and lower median premolars and the upper 

 canines erupt between the eruption of the upper and lower 

 lateral premolars. 



