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THE POPULAR SCIENCE MONTHLY 



Lung Capacity Corves. Boys. 



The base line divisions represent periods of one year ; the vertical divisions repre- 

 sent 20 cubic inches in lung capacity. The degree of pitch of the line shows the 

 relative amounts of increase of absolute increments for the same individual. 



interim, provided his relation to any given median or norm be known. 



The second significant point to notice is the relative shifting of the 

 period of adolescent acceleration from 12^ for the tallest boy (No. 2) to 

 16 years for a short boy. For the tallest girl maximum height was at- 

 tained at 14^ and for the shortest girl at 17 years, 3 months. 



A period of marked retardation before adolescence is usually marked 

 by a period of rapid acceleration during adolescence. If the increment 

 of growth before adolescence is uniform, this uniformity tends to persist 

 throughout adolescence. Where there is unusually rapid growth from 7 

 to the beginning of adolescence, there is frequently a decrease during 

 adolescence. Marked arrests with these children usually occur during 

 adolescence and persist throughout the period. 



As a rule the weight and height are relatively proportionate to each 

 other. Aside from irregular periodic fluctuations in height, each child 

 retains relatively its position throughout childhood in regard to weight. 



