Evening star., 1934-09-19
BONE DEPRESSION
EVOLUTION INDEX
Entire Life History of Def
mite Human Feature
Is Chartered.

Is Chartered.
BY THOMAS r. HENRY.
A child grows up" in many direc-
tions and at many speeds.
His growth is the sum of thousands
of separate growths which, somehow
or other, happen to f1t together SO
that specifically it looks as if he was
growing up as whole. But some
parts of him may have reached de-
crepit old age before other parts Of
him have passed their infancy.
Such is essentially the conclusion
reached by Dr. Ales Hrdhcka. curator
of physical anth-opology of the Smith
sonian Institution. A case in point is
his extensive study. the results of
which have just been announced. of
curious depression in the thigh bone
the hypotrochanteric fossa of the an
stands out as q sort
of index Of evolution.
Peculiar Relationship.
1t shows some peculiar relationships
which lead to rather far-reaching de-
ductions. The feature appears in man.
chimpanzee. gorilla and orang-outan.
It is not found in the Old World mon
keys, but there is an occasional trace
of the hollow in the gibbons and the
New World monkeys.
In the great apes it serves a def
mite purpose. 1t is a place Of at
tachment for one of the large thigh
muscles. It shows a progressive de-
velopment with growth, as normally
would be expected of any physical
feature. until the individual has
reached its full size. Quite often 1t
is missing altogether in the young. but
almost invariably appears in adult
bones.
Man presents a quite different pic
ture The fossa in humans may make
its first appearance as early as the
fourth month before birth, although
the time is irregular and it may come
at almost any period in childhood or
sub-adult life. The striking fact is
that it attains its greatest develop
ment-which in man may be quite
small-before maturity and then be-
gins 10 disappear.
Sometimes it undergoes its complete
development and deterioration during
childhood In man it either has no
function or very minor one.
Whole Life History.
The study Of this fossa, says Dr.
Hrdlicka, is the first practical instance
in anatomy and anthropology of
viewing "the whole life history Of a
definite feature in human morphology.
This life history could be presented in
the form of a curve of long but steady
ascension, a mildly rounded or fiat
summit, and then a prolonged descent
to below one-half of the earlier rise.
And there are indications-in some
instances definite proofs-that every
single organ or part of the human
body, and every human function. too,
has its own extensive and highly in
teresting life history. history con-
nected in its origin with human der
ivations and antiquity, and ending in
advancing repression and apparent
preparation for disappearance; or in
seeming tranquility. or some degree
of progessiveness toward q greater
representation. The realization of
these conditions opens vast and at
tractive field for future researches.
The stories of the existence histories
of the innumerable components of
human structure and functions are
the most alluring realms of the an
thropology of the future
Apparently, DR.. Hrdlicka points out,
the fossa was derived by both man
and the apes from a common ancestry.
The body of the ape evolved In a way
which made it an essential feature
through life. Consequently its growth
curve is roughly comparable to that
of the whole complex of organs max
ing up the individual animal.
Mans development was in diff
ferent direction. II the foSsa served
any purpose at all it was in the early
years. Once the body had attained its
full growth, the hollow in the thigh
bone was apparently useless. Conse-
Quently its whole life history trans
pires in a relatively brief period. It
is like story within a story.
Curiously enough, the bones of
human precursors - Pithecanthropus
and the various Neanderthaler spec
imens-show no essential difference
from modern man. The skeletal ma
terial available for study, however, is
rather limited. There appear to be
slight race and sex differences in
human bones, the significance of
which is somewhat obscure.
DR.. Hrdlicka's study was made pos
sible by the great assemblage of ape,
monkey and human bones of all ages
and races which has been brought to-
gether at the National Museum. Later
the separate life curves of other
anatomical features may be studied in
the same way in an effort to lay the
groundwork for disentangling the
great complex of growth which con-
stitute the growth of the whole.