Coulee City dispatch. [volume] (Coulee City, Wash.) 19??-19??, 1929-12-20
WHY WE BEHAVE
LIKE HUMAN BEINGS
By GEORGE DORSEY. Phi. D.. IL. D.
What Makes Giants and
Dwarfs.

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dog, in eight. We increase our weight
200 per cent in the first year, less than
80 in the second, only 5 in the fifth.
Increase in weight then picks up again
and continues until the tenth year,
to drop back from the eleventh to the
thirteenth. From the fourteenth to
the seventeenth, puberty years, 1t in
creases again, to IL per cent. That is
our last squirt. It drops to per cent
during the eighteenth year; to 1 per
cent during the twenty-second.
Stature also increases by spurts. By
the time the infant can walk, 1T has
grown from twenty to thirty-four
inches; thereafter, until puberty, it
grows between two and three inches
year. The thirteenth is the rapid grow
ing year for girls, the sixteenth for
boys. Between fourteen and sixteen
the boy increases his stature eight
inches. Girls usually attain their full
stature by twenty, sometimes by eigh-
teen; boys by twenty-five. But both
may continue growth three or four
years longer.
The new-born's brain is already one
fifth the destined weight, about ten
ounces; by the second year two-ffths,
or as large as an adult anthropoid
apes. Full brain weight comes before
twenty-five; after that it loses weight,
rapidly in old age.
The two elements in growth are
weight and height Weight often con-
tinues beyond maturity, long after the
body has taken on Its last cubit. The
giant can grow no taller; the fat lady
knows no limit.
Stature is determined almost en-
tirely by the skeleton. Only skin and
q thin layer of fat cover skull and the
bones Of the feet; thin cartilage COW
ers the ends Of the leg bones between
the vertebrate are thin pads of car
tilage Stature growth, then, is largely
matter of growth of skull, bodies of
vertebrae, and especially of the leg
bones.
Bones grow from centers of ossifica-
ton. Centers for the principal bones
of the body appear by the end OF the
second month of fetal life; centers for
the ends, or epiphyses, appear later
many not until puberty, when the
skeleton begins to assume it's perma-
nent form.
The number of Justification centers
varies in different bones. The long
bones of the arms and legs have at
least three: one In the shaft itself
and one at each epiphysis. The hum
erus at fifteen years is still in three
parts: shaft, two heads; but the heads
are more closely connected with shaft
than at birth. By maturity, the heads
are SO united with the shaft that it is
not possible to see where they grew on.
In general, facial and skull-dome
bones are formed from membrane
''skin" bones; the other bones begin
in cartilage. BOne-formfng cells multi
ply by division, absorb lime salts from
the blood, ossify, and so continue until
the cartilage is replaced by bone. In
crease in length ends when the cartil-
age disappears. In the mature skele-
ton there can be no further growth
in stature or in length Of arms. II
final conversion of cartilage to bone
is delayed, gigantic stature results; If
the process is reversed, dwarfs. Only
| the articulating or joint surfaces of
mature bones are covered by cartilage.
| Bones increase in girth by additions
of bone cells from the surrounding
membrane. Long bones are hollow. To
preserve their relative proportion Of
bone wall to cavity, bone cells on the
inside are destroyed as fast as cells
are added to the outside. Thus the
cavity grows with the bone, the form
and strength of the bones are pre-
served. This process keeps up until
late in life. With old age the bones
become thin and delicate.
Complicated changes take place in
acquiring the upright gait. A chick
can run from its shell; baby cannot
even straighten its legs. They bend in
at the knees and are drawn up at the
hips, and are only go per cent Of
head-trunk length. By maturity they
will be over 100 per cent. AS the walk
ing days approach, the legs grow fast.
Knee and hip joints change; the legs
can now be Strengthened out. The soles
of the feet no longer turn in. The baby
at birth can clap it's feet almost as
easily as it's hands.
The spine also changes. It Is not
solid, but consists Of twenty-four YER
tebrae with pads of cartilage between.
At birth large percentage of the col
umn is cartilage. Powerful muscles
develop to hold the spine erect; 9TH
ers, acting on the ribs as levers, to
balance the trunk and spine.
Standing is complex act involv-
ing nearly all our big muscles. When
we stand TAT attention." powerful liga-
ments in the hip joint hold the body.
This relieves the muscles from strain,
but locks the knee joint. We stand
easier If the knees are slightly bent
and the knee-caps loose.
The feet muscles must bind the
many small bones together to give
support and from the instep or arch.
A man can stand up asleep, but not II
muscles Of feet or Of legs are asleep"