Ill 



OF GROWTH IN CHILDHOOD 



105 



Stature and weight of American children (Ohio) 

 (From Katherine Simmons and T. Wingate Todd's data) 



Mean of observed incremeyits of stature and weight of 

 American children 



Increment of stature (mm.) Increment of weight (lbs.) 



These differences between the two sexes, which are essentially 

 phase-differences, cause the ratio between their weights to fluctuate 

 in a somewhat comphcated way (Figs. 10, 11). At birth the baby 

 girl's weight is about nine-tenths of the boy's. She gains on him for 

 a year or two, then falls behind again ; from seven or eight onwards 

 she gains rapidly, and the girl of twelve or thirteen is very httle 

 lighter than the boy; indeed in certain American statistics she is 

 by a good deal the heavier of the two. In their teens the boy gains 



