Evening star., 1937-02-23
STARS, MEN AND ATOMS
,tebook Of Science Progress in Field,
Laboratory and Study.
BY THOMAS r. HENRY.

A new age scale, applicable from
birth through adolescence, which is
based on the progressive development
Of the bones of the hand, Is proposed in
q monograph Just issued by the Society
for Research in Child Development Of
the National Research Council.
The scale was constructed by DR..
Charles D. Flory Of the University Of
Chicago on the basis Of hundreds Of
X-ray pictures Of the hand. The COM
mon age-scale Of birthdays, 1t Is pointed
out In the report, really means very
little during the formative years OF LIE.
The fact that two children are each 10
years old chronologically cannot be In
terpreted as meaning that they have
reached the same stage Of physical de.
velopment. Some mature, mentally and
physically, earlier than others.
But the bones Of the hand, DR.. Florys
study shows, are indicators Of the pace
at which the body is developing. There
Is an average development, for example,
for l0-year-old boys. Any individual
may be q year or 20 ahead or behind
this average. He Ii 10 years old chrono-
logically, but or II years old skeletally.
It 10 unfair to compare his progress
with that Of 1o-year-old boys as Q class.
There IL an entirely different skeletal
scale for girls.
The report contains q series Of pic
lures representing the norms for both
sexes from birth to 18 years. The de-
velopment Of any individual can be de-
termined in relation to these norms.
The 12-year-old boy who falls behind
in competition with other 12-year-olds,
it is pointed out, may actually be only
II years old in development and hence
subjected to an unfair comparison.
Girls. DR.. Flory's study shows. are
colder" than boys Of the same chrono-
logical age-a fact which may have an
important bearing on future studies OF
sex differences.
"There is" he says, "a gradually In
creasing sex difference ss children ad-
vance in age. The typical e-year-old
girl IL skeletally about as mature as the
typical 7-year- r-old boy. Boys and girls
are practically o year apart when they
enter the elementary school and ap-
proximately two years apart when they
enter high school. That Is, high school
pupils Of the same chronological age
show about two years Of sex difference
In skeletal development. These facts
must have some influence on scholastic
success, mental development. and the
social adjustment Of pupils as they pass
through high school.
1.-THE fact that q child IL born o boy
instead Of o girl predetermines that his
chances are very good to reach ma
turity at an age somewhat beyond the
average for girls. Individual growth
must be considered in relation to the
average for the sex group to which the
child belongs"
Within these sex groups, DR.. Flory
stresses, due allowance must be made
for individual variations. Nearly every
one falls somewhere around the average,
but at the same time everybody has an
individual growth rate and there is
some evidence that this is hereditary.
Brothers and sisters tend to deviate in
the same direction from the average.
The range of variability among ind1-
viduals, he found, is relatively small in
infancy, but increases with age until
the early teens. It tends to decrease
with age In late adolescence.
Says Dr.. Flory: chronological age
has long been used to determine when
children should enter school, when youth
might leave school to begin work, when
young people are allowed to marry. and