The Washington herald., 1922-04-16

tion and variation such as we see
in the case of man in America in
dicate that the organisms concerned
have been on this continent such A
short time that there has been little
opportunity for physical differentia-
ton to take place: and that the
American forms are evidently de-
rived from an Asiatic source.
The physical characters Of man
generally resemble those OF the
apes so clearly that discussion of
this relationship inevitably resolves
itself into a search not for SINH
lsrities but for differences.
1t is possible that some OF the
structural features have no relation
to the question OF ancestry of the
human skeleton. On the other hand,
as in the case of the ribs rudiments
lying between the vertebrsl column
and the hip bones, and in the
growth of the first two vertebrae,
there is every reason to believe that
the mode of development CORE
spending to that of the reptiles in
these portions Of the body is not
related to specific needs of the skel-
eton of man considered either as
completed or in the process OF growth,
but that 1t represents rather mode
of development initiated in a stage
earlier than that Of the higher ami
mails to which man belongs and
persisting in man by reason OF the
fact that even at this stage in evo-
luton 1t offers no distinctly unfa-
vorable features.
The anatomical characters dis
tinguishing us from the anthropoids
are generally considered to be most
sharply expressed in form and d.
mensions Of the brain and skull. and
in the form and function of the
posterior eXtremities. Difference in
brain capacity is accompanied by
skull distinction Of which the most
readily recognized character is seen
in the relatively large size and
prominence OF the jaws in apes.
In some respects the difference
between man and the apes seems as
clearly expressed in the limbs as in
the brain, especially since the diff
ference is not merely one of degree.
but is in the limbs a distinction of
kind and function. In most apes
the relatively long fore-limbs are
the principal structures for locomo-
tion, which is by swinging through
the trees. and to some extent the
hands of these limbs serve the head,
though the thumb Is not generally
opposable. The hind limbs af the
apes are used for grasping and the
feet. with opposable first toe. serve
as hands.
In man the relatively long pos
terror eXtremities are used solely
for walking. The anterior extrem-
tiles with opposable thumb of the
hand serve the head, and as one
among many other functions they
may be used for climbing. The op-
possible thumb Is specialized to a
high degree. and freedom from use
in locomotion permits the hands
great development Of skill IN many
directions. In apes there are really
four hands. but the pair with oppos-
able first digit is situated on the
portion of the body farthest from
the head. so that neither pair is ad-
vantaged to specialize after the
manner of the hand of man.
To most students of the problem
of structural similarities and diff
ferences distinguishing apes ana
men. the greatest divergencies not
ed are to be classed as differences
in degree rather than in kind. This
seems in large measure true of skull
and brain. The difference in foot
structure possibly presents the
widest separation and indicates
distinction in habits of life condi-
toned upon locomotion. Yet even
with the widest gap that we can
open. the apes are still so near us
that with man recognized as a bio
logical type he must. when classi-
fed. take his place in the line next
to the chimpanzee and the orang.
The conclusion which we obtain
from a consideration of the biolog-
ical aspects of the human problem
is that physical man may not be
separated from the geological
scheme. The sum OF evidence from
human physical structures gives us
an organism dependent upon typi-
cal biological processes for its ori-
gin and constructed nm the tYnical