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 The base line divisions represent periods of one year; the vertical divisions represent 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 attained 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.