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TEE POPULAR SCIENCE MONTHLY 



Height and Weight Curves. Boys. 



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

 resent 5 centimeters in height and 10 pounds in weight. The degree of pitch of the 

 line shows the relative amounts of increase of absolute increments for the same in- 

 dividual. The broken line shows Boas's norm. 



In reply to the question how tall or how heavy is the normal child 

 within this group, and how much lung capacity has this child, the dis- 

 tribution tables give the following medians in inches, pounds and cubic 

 centimeters, respectively. 



For the boys and girls below the median or normal height, the 

 period for accelerated growth in height, weight and lung capacity is 

 later than for those above and the growth continues longer. This is true 

 of the schools individually and collectively for yearly and half yearly 

 increments, and for the per cent, of gain over the initial measurements. 

 In conclusion the nodes of acceleration or cessation are different for tall 

 children and heavy children than for short and light children. 



In answer to the question, " What relation does the growth of any 

 one age or period have to subsequent ones ? " it can be said that the per 

 cent, of gain from year to year shows that each child remains practically 



