The Pulaski citizen. [volume] (Pulaski, Tenn.) 1866-current, 1874-08-13
The Color of Animals.

A contributor to Chambers Journal,
discoursing on " the color OF animals,
presents many interesting facts on a
subject that is receiving the special at
tention alike of chemists, physicists, and
students of natural history. We con-
dense from this paper as follows: The
rather antiquated idea, that all the
lesser members of the animal kingdom
were created for the service or admira-
ton of man, is repudiated for one rea-
son, among many, that " fishes IN the
depths of the Indian seas, where no
human eye can see them, possess the
most gorgeous tints." The- careful OBJ
server, who directs his attention to the
subject, wi be struck by the fact that,
while birds, fishes, and insects, possess
the notwithstanding, 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
dark tint, while the other side is white.
| In the case of birds, however, this dis
| in an atmosphere that is more completely
luminous. The wings of many butter
! flies, for like reason, are as beauti-
| fully feathered below as above. In
further support of this theory, that the
| cylor is mainly due to the action of
| light, the neutral tinte of the molluscI
that live in closed shells are cited, also
the pale color OF the Larvae of insects
found in ground or wood, and the white
ness of those curious little beetles in
habiting the inaccessible crevasses of
snowy mountains, in whose depths they
| are hidden. tits furthermore observed
that, so far as concerns the color of an
| imais, birds, and insects, those are the
most brilliant which are exposed to the
sun, those OF the tropics being brighter
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 a richer shade whore 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 al
a greater depth. Those who bring uI
goldfish are careful.to afford thempro.
lection against the direct rays of thesun
without which precaution they soon lose
their beauty. Passing from these factl
) to brief discussion of the causes which
result in these peculiarities of colol
and tint, we learn that, while in certain
8 cases the color is due to the molecular
! arrangement of the living substance
/ this is not usually the case. Sometime
these colors arise from a phenomenon
like that by which the soap-bub
BILE shows its prismatic hues sometime
there is q special pigment which i
united with the organic substance, a
; in the brilliant paint carmine, which
!, the pigment of the cochineal insect
The color left on the hands after hold
ing a butterfly is another instance, an
there are Ger ain birds, such as tn
large white cockatOo, which leave
: white powder on the hands. OF tn
> chemical constitution of these variou
I pigments, little seems known, It
more ordinarily found in the depths {
the tissues reduced to fine particles
i When the particles are scattered, the
scarcely influence the shade but Whe
J near together, as in the case of the NJ
=, gro, they give character to the surfaC
u exposed. Age takes it away from th
hair. when it turns white, the colorinl
matter giving place to small air bull
. bles. There is another and q large o.
/ der of animals, including many bird
and fishes, in which the sole cause {
color is the play of light over the e.
= posed surface. When the beautifI
3 feathers of a humming- bird are exam
. ined under the microscope, they apes
y to be simply made of a dark brown
d Opaque substance, not unlike those
= the black duck, and to the arrangeme1
y of these dark plates the changes an
e brilliancy of their colors may be a
% cribed. The many-hued shades {
fishes are due to the same cause.