American citizen. [volume] (Canton, Miss.) 1864-1890, 1875-09-18
Bones.

When a new bone finds its way into the
tudent's hands he observes, says Prof.
Elwin, some peculiarly in shape or
structure in which il differs from the bones
ne is already acquainted with; the ques-
lion naturally occurs to him: Why does
his bone assume one shape in one animal
and in another is modified into different
form? He may look in vain in his books
for an answer to his query. And yet it
is points like these which, in my opinion,
make up the true science of osteology. 1t
is through careful, constant and intelli-
gent observation that these enigmas are to
be solved. Observation, indoors and out;
close attention to the habits of the animal
in question on the one hand, and careful
consideration of its anatomical peculiar
tiles on the other.
Take the skull of crocodile. What do
we finds The orbits of the eyes, the nasal
orifice, the passages leading to the auditory
apparatus, all situated on a plane along
the upper fiattened surface of the head.
What, then, is the cause of this? Palpa-
bly,, to allow the crocodile to remain SUBJ
merged in the water, with its nose, eyes
and ears just above the surface to warn
him of the approach of enemies or prey,
and the rest of his carcass securely hidden
beneath the waters.
Take another instance. Observe the
u
burrows under ground, shoveling away
the earth with its fore feet. Then look at
its skeleton. We find just what We
should have expected. The bones of its
fore legs # astounding strength and
breadth, furnished with deep grooves,
which, together with its sternum or breast
bone, which is furnished with a keel
almost like that of the sternum of bird,
afford attachment to the powerful mus
cles. Its hind legs, being simply needed
for locomotion, are of the normal size. So
also with the birds. The size of the keel
of the sternum varies in proportion to the
power of flight which each species re-
quires, for it is to the broad surfaces of
the sternum that the great wing muscles
are attached. Take the skeleton of a hum
ming bird, which spends his life almost
upon the wing. We find there keel Of
so vast size that the remainder of the
skeleton is reduced to insigniicance in
comparison.
by the fact that in the notifications in va
rfous bones, or sets of bones, IN accordance
with the habits of each animal, the orig
inal type is never departed from, only
modified. See, for example, the paddle
of q whale, more like the fin of a fish in
general appearance; and yet the SAND set
of bones which0re found in the arm of a
man are again found in an adapted form in
the paddle of the whale. So, also, the
foreleg of horse preserves the sameg gen.
eral plan. What is generally called his
knee 10 in reality his wrist II isstherc
that we find the little group of bones
which form the corpus. All below it an
swers to our hand-a hand consisting of
one finger.
Take even q wider instance Compare
the arm of Q man and the wing of q bird.
still greater adaptations have taken place
and yet the plan remains the same. We
still find the clavicle or collar bone, the
scapula or shoulder blade, the humerus,
ulna and radius, answering to the same
bones of our arm, a small carpus or wrist,
and finally the phalanges or fingers, sim
plified and heightened and anchylosed to
form but one series of bone, with the ex-
ception of rudimentary thumb. 1t Is not
to find a rudimentary bone
like this which, in some allied species, is
fully developed. The leg of the horse
again gives us very striking example of
this. There is, so to speak, only single
finger, but we find, one on each side of
this little finger, two small bones, CON-
monty known only as splint bones. These
are the rudimentary traces of the sane
finger bones, which in the rhinoceros are
fully developed. =.
Now osteology abounds in wonderful
FORMS of structure like these. 1t is q study
pregnant with plessufable results, and is
> really pFodtabls stfdy, and one in which
each frcsh student may do real solid
work. It is all The little facts observed by
naturalists, from time to time, all over
the world, which, on being collected to-
gether, form the nucleus Of knowledge,
for indeed all the scientific knowledge
which we possess Is little more than
nucleus with which we are supplied
Science Gossip.