HBDLicKA] PHYSIOLOGICAL AND MEDICAL OBSERVATIONS 97 



Among the whites the teeth that appear next are the upper lateral 

 incisors, the eruption of which takes place during the ninth month. 

 These teeth had just broken through in an Apache girl of 7 months 

 and 20 days and in a Pima boy of 7 months and 17 days, while the 

 oldest children in whom both were still lacking were an Apache girl of 

 14 months and a Pima girl 1 year and 16 days old. The average date 

 of eruption is-probably very close to that in whites. Again retardation 

 was more frequent in the Pima. 



The lower lateral incisors, which in white children erupt on the 

 average during the latter part of the tenth month (D.), were seen 

 earliest in an Apache girl of Sh months and in a Pima girl of 9 months. 

 The oldest Apache child in whom both were lacking was 12^ months; 

 the oldest Pima child 18 months and 2 days old. In three instances 

 one or both of these teeth were out before the upper lateral incisors. 



Among whites tlie teeth which appear in most instances next after the 

 incisors are the upper and then the lower anterior premolars, and the 

 average time of their eruption is the thirteenth month. The canines 

 follow, ^appearing on the average from the middle to the end of the 

 fifteenth month (D.). Among the Apache children in two cases all 

 the anterior premolars were out before the appearance of any of the 

 canines, and there are indications of similar precedence among the 

 Pima, the order of eruption thus agreeing with that in whites. As 

 to the time of appearance, in the Apache the anterior premolars were 

 not present in any child up to 14 months, but were found in all 

 of 16f months and older, while in the Pima the teeth were not erupted 

 in any subject up to 15^ months, and w^re present in all but one 

 (wdiere the lower were still wathin the gums) of the children of 17^ 

 months and older. The eruption of these teeth appears to take place 

 somewhat later in the Indian than in the white child. The canines 

 were seen first in an Apache girl of 19 months 10 days, all being 

 present in every older child, and in a Pima girl of 17^ months, being 

 present in all but two older subjects (of 18 months and 18 months and 

 2 days respectively). Here again a comparison with white children 

 indicates some retardation in the Indian. Unfortunately the number 

 of Indian children studied is very limited and the point can not be 

 considered as decided. 



The posterior premolars, which appear in whites between the twen- 

 tieth and the thirty-third month (D.), were all present in an Apache 

 child of 19 months 10 days, and in another of 20 months; these had 

 not all erupted in three Indian children of from 22 to 23 months of 

 age and were wholly lacking in one of 25 months, but were all present 

 in every case from 26 months upward. Among the Pima none of 

 these teeth were found in children of 2 years or younger; the two 

 lower were present in a boy of 25 months, and were just appearing in 

 another of 26 months and 9 days, but were all present in every sub- 

 3452— Bull. 34—08 -7 



