128 ROBERT BENNETT BEAN 
Filipinos are likewise more precocious than the Americans, who 
are slightly more precocious than the Germans. 
There is an alternation in the periods of acceleration and retar- 
dation in the eruption of the permanent teeth, and there is also an 
alternation in the periods of acceleration of the growth in stature 
and the periods of acceleration in the eruption of the permanent 
teeth. 
3. The time of eruption of each individual tooth 
This is to be determined for each sex and race by means of the 
beginning of eruption, the end of eruption, and the average per 
cent of the teeth erupted at specified ages during which time the 
teeth are erupting in all the groups. The beginning of eruption 
may be utilized: that is the time at which the tooth first erupts 
in any individual in a race-sex group; the end of eruption, that 
is the time at which the tooth last erupts in any race-sex group; 
the 'median,' the time half way between the beginning of erup- 
tion and the end of eruption, may be taken as the time of erup- 
tion; or the time when 50 per cent of the teeth of any type have 
erupted in a sex-race group may be taken as the time of eruption. 
For purposes of comparing the groups with each other the 
average number of teeth erupted at the ages in which all the 
comparable groups have the teeth erupting at the same time may 
be utilized. This may be called the average per cent. As, for 
instance, the right upper second molar is erupting in all the groups 
during the ages of 12, 13 and 14 years, and the average per cent 
erupted at these ages is as follows: 
per cent per cent per cent 
Filipino boys 85 American boys 53 German boys 51 
Filipino girls 94 American girls 68 German girls 58 
From this we may gather that the Filipinos are more preco- 
cious than the other two groups, the Americans are more pre- 
cocious than the Germans, and the girls are more precocious than 
the boys in the eruption of the right upper second molar teeth. 
The median incisors. The median incisors begin to erupt in 
some individuals before the age of five years, and the teeth are 
