Porter — Physical Basis of Precocity and Duliness. 181 
This difference persists for about three years, and then the 
curves once more cross and the youth is once more heavier 
than the maid. In Plate II, the curves of girls’ weights cross 
the boys’ curves at the same age in dull, mediocre andprecocious 
children. The point in the period of accelerated development 
at which girls become heavier than boys is the same in the 
dull, the mediocre and the precocious. 
The conclusions reached in this investigation are based 
on means and averages. How far they are applicable to 
individuals cannot be determined from the present data. 
For this, another method must be used. The same children 
must be weighed from year to year. The variation of the 
individual from the normal mean or average will then be 
known. But even without this information, a deduction of 
great practical importance can be made from the laws 
established by the present research. Mo child whose weight 
is below the average of its age should be permitted to enter 
a school grade beyond the average of its age, except after 
such a physical examination as shall make it probable that 
the child’s strength shall be equal to the strain. 
Issued March 21, 1893. 
