The Wheeling daily intelligencer. [volume] (Wheeling, W. Va.) 1865-1903, 1874-05-09

Inherently COlOIeQ varieties OF The ufAl
butterfly are found, the protected kind
initiates the change perfectly. Every spoI
and line orc accurately copied, and even
the lazy mode oil flight Is simulated. In
all cases the protected insect is much lesl
numerous than The other, as otherwise
the resemblance would DO insufficient Of
a safeguard, and It has evidently arisen
from natural selection, as several varle-
ties Of diurnal moths have similarly
initiated the appearance Of these NAL
odorous buttafeg The colors Of the
Veg6tAl Kingdom may. be explained By
reference 10 natural selection In an equally
satisfactory manner. "Flowers," says
Mr. Wallace, do not often need protec-
ton, but very often require the aid Of in.
sects 10 lertlllzc them, and maintain their
treproductiye powers in thegfeatest vigor.
Their gay colors attract insects, as do Also
their sweet odors and honeyed Secfetions
and that this 10 the man junction of color
In flowers Is shown by the striking fact
that those plants which can be perfectly
tertilized by the wind, and do not need
the aid Of insects, rarely or neUer hdus
gatly c9lored tOIotra," IN 5t =
THESE PHENOMENA BxPLIcABLE DY NAT.
,,,o uRAL sEIRoTIoN.
The fact that all our domestic anifrtnrals
with their variability OF color. have de-
scended from q wild progenitor having q
relatively fixed and definite color, shows
that there IS no innate physiological no.
cesaity Tor any animal possessing q char
acteriStic style Of coloring. II Is quite
obvious that in q state Of nature indi-
viduals whose hues rendered them con-
spicuous would be most easily avoided by
their prey. and most readily perceived by
their enemies, and that thus they will
tend TO less frequently survive and per-
petuate their kind. Now, five attribute
the protective hues Of animals in q wild
state to tho action Of natural selection,
we can readily understand why, among
their domesticatedr descendants, such Q
variability ofcolor should be found. Re.
lieved from the exigencies Of ierine lie
there Is no longer any imperative necessi.
| ty for concealnont. Unfavorably color.
ed individuals are preserved equally well
with those retaining the normal hue, and
varieties will appear among members Of
the same species. Thus we may see why,
In the domestic cat, which, was originally
arboreal in It's habits, black, white, and
various other colors should occur,
although there is manifested a frequent
tendency to feyiye the mottled spots Of It's
progenitor, tho wild cat. Thus, too, we
may comprehend why the females of
birds which build open nests should be
dull colored, like their dwellings; while
conversely, the females Of birds which
build. domed or covered nests should
often have as brilliant plumsge as tho
males,
OTHER FACTORS IN TIE MODIFICATION OF
sPRcIKs. a..
There are several other elements which
serve as suxilliaries 10 natural selection
in eftecting the gradual change OF vari-s
cites into species, and the slow transit
ton oI species into distinct genera. Two
Of these which answer an important pur-
pose, are, use and disuse, and correlation
OF growth. To illustrate the latter, ."let
US suppose that 1t becomes advantageous
to some feline animal, like the ancestor oil
the lion, TO have large and powerful Jaws.
Natural selection would preserve all the
strengthened individuals and in the
course Of lew generations our race oil
leonines would possess on the average
much larger and stronger jaws than ut
the period at which we began 10 consider
it. But greater weight ofjsws entails in.
creased exertiOn Of tho muscles which
move the jaw, so that these muscles.zre-
ceiving more and more blood, will be-
come permanently increased In size and
power. The portions Of the skull into
which the jaw bones 1t will likewise re-
ceive an extra strain, and will .conse-
Quently increase in rate OF nutrition and
grow TO larger size, so that the shape
OF tho whole head will be altered. THIS
increased weight Of the head, and the
increasingly violent activity oil the mus.
cles which move the jaws, entails o
greater strain upon the .vertebrae which
support the head, and upon the cervical
muscles which move it from side TO side.
The heightened nutrition OF these bones
and muscles will add to their weight so
that the shoulders and chest will be at.
lected. There will be a tightening Of
the ,tend6ns, and probablyaa perceptible
alteration in the relative length Of the
different bones and muscles throughout
the anterior part Of tho body; and these
changes, altering the animals centre Of
gravity, wiltinevitably cause other COM
pensating changes In the rest Of the body!
The legs, shoulders, and launches, will
be modified. Alterations In the weight
bearing upon tho chest will affect the
growth OF the lungs and the aeratlon OF
the blood. And tho stomach; lintestlnes,
and various secreting glands will respond
10 the requirements Of all these nutritiye
changes. While lastly, such deep-seated
variations cannot fail to influence the
nervous system Of the animal, and to
modify somewhat Its temperament and
Its modes Of lfe." en- IS alma, i
THE OPERATION OF USE AND DIsEsE.
BY way Of illustrating the effects ofu
and disuse, let US again consider the case
OF tho antklopes These Features, through
the constant exercise Of their perceptiVe
powers and organs oitilghtcon with
the natural selection and survival Of the
individuals most strongly possessing these
qualities, have, become lamongthe fleetest
and most timid OF qusdrupeds. Let US
now suppose that tho carnivora, which
formerly preyed upon them, ahad from
some cause disappeared from their dis
trict. 7" Relieved from tho necessity ofrun.
ming from danger, the antelopes would no,
longer. exercise their limbs with the se-
we're strain which pursuit had imposed.
upon them. BUTT isa law Of physiology
that functions can be kept at their maxi
mum Of vlgory only BY constant employ
ment, and tho inevitable result Of this
desuetude would be to decrease the speed
and alertness o. the animals go, that In q
few, generations, the average qualities In
these respects would BIO considerably al,
tered, This modification would In It's
turn be supplemented by correlation Of
growth, and tho digestive, region would