The Hickman courier. [volume] (Hickman, Ky.) 1859-current, 1874-08-07
The Color OF Animals.

A contributor to Chambers Journal.
discoursing on 1.-THE color of animals, y
presents many interesting facts on a
subject that is receiving the spesiaI at
tention alike of chemists, phycicista. apd
students OF natural history. We con-
dense from this paper as follows: The
rather antiquated idea, that all the
lesser members of the animal kJ-gdon
were created for the service or admira-
ton of man, is repudiated for one req
son. among mary, that q fishes IN the
depths of the Indian seas, where no
human eye can see them, possess the
most gorgeous tints." Tha careful OBJ
server, who directs his attention to the
subject, WI be struck by the fact that.
while birds, fishes, and insects, possess
the metalic,coloring, zoophites, like the
flowers to which they seem closely al
lied, are without rejecting shades.
Pursuing our Investigations further, it
is nOted that among animals, the part
of the body turned toward the earth,
that is, away from the light, is paler
than that which Is uppermOst. Marked
instances of this are found in the sole
and turbot, each of which have the left
side, which answers TO the back. of a
dark tint, while the other side is white.
In the case of birds, however, this dis
t notion is less marked, since they i've
inan atmosphere that's more completely
luminous. The wings of many butter
flies, for a like reason, are as beauti
fully feathered below as above. In
further support of this theory, that the
oJlor is mainly due to the action of
light, the neutral tints of the mollusc
that live in closed shells are cited, also
the pale color o the larvee of insects
found in ground or wood, and the white
ness of those curious little beetles in.
habitlng the inaccessible creyasseS
snowy mountains, IN whose dem <:
are hidden. 1t is furthermSs<
that, so far as concerrs=-s~s< - -
imals, birds, and insects, tnO-lJ - :; =
most brilliant which are exposeCs,ds -
sun, those OF the tropics being brigntusu
hued than in the regions around the
north-pole, and the diurnal species than
the nocturnal. Marine animals seem TO
form an exception to this rule, and are
of richer shade where the light is
more tempered. The most dazzling
corals are those which hang under the
natural cornices of the rocks and on the
sides Of submarine grottoes. Fishes that
are found in shallow water are less
brilliant in tint than those obtained at
a greater depth. Those who bring up
goldfish are careful'to afford thempro-
lection against the direct rays of thesun,
without which precautlon they soon lose
their beauty. Passing from these facts
to brief discussion Of the causes which
result in these pecuharities of color
and tint, we learn that, while in certain
cases the color is due to the molecular
arrangement of the living substance,
this is not usually the case. Sometimes
these colors arise from a phenomenon
like that by which the soap-bub-
bic shows its prismatic hues sometimes
there is q special pigment which Is
united with the organic substance, as
IN the brilliant paint carmine, which is
the pigment Of the cochineal insect.
The color left on the hands after hold
ing a butterfly Is another instance, and
there are certain bicds, such as the
large white cockatOO, which leave a
white powder on the hands. OF the
chemical constitution Of these varf us
pigments, little seems known. 1t IS
mere ordinarily found in the depths OF
| the tissues reduced TO fine particles.
| When the particles are scattered, they
scarcely influence the shade but when
near together, as in the case of the ne
| gro, they give character to the surface
| exposed. Age takes IL away from the
/ hair, when it turns white, the coloring
matter giving place to small air bub
| bles. There is another and a large OF
! der of animals, including many birds
and fishes, in which the sole cause OF
color Is the play of light over the ex.
/ posed surface. When the beautiful
/ feathers of a humming bird are exam.
/ ined under the microscope, they appear
to be simply made of a da,k. brown
/ Opaque substance, not unlike those o
the black duck, and to the arrangement
| of these dark plates the changes and
| brilliancy Of their colors may be as
! cribed. The meny-hued shades OF
| fishes are due to tho same Cause.