The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1897-12-28
AMERICAS CHAMELEON.
Description of How the Florida Liz
ard Changes It's Color.
Letter in Observation-Disclosures.

Letter III Scientific American.
These. little creatures were about five
inches in length, of a general dark green
nue. Shading to gray, assimilating the va
rtous objects upon which they rested slowly
t put very decidedly / arranged several lit
with gray. another with a green, and
changed the occupants about. In ten or fif
teen minutes they very materially would
adapt themselves to the very tint though
they never became white, the change then
being merely fading out of all lines, leav-
ing the body faint gray. AT night they
became beautiful green, which may be
considered their normal color. The changes
made in confinement 1 am confident were
not so rapid as those when lizards were in
their native Florida, where moisture and
hot days and nights gave them the exact
temperature necessary for their best dis
plays.
There is something mysterious and even
uncanny In watching the change of color.
creature would Immediately draw itself out,
extend its front and hind legs at full length
and become to all intents q part of the twig
guish it, Meanwhile the mysterious blush
or green was deepening and stealing over
it's back and Sides making the resemblance
still more striking The natural assumption
of one who had given the subject no espe-
cial attention might be that the anoiis had
glanced around, and, perceiving that it was
presenting a contrast not favorable to its
personal safety, had assumed color more
protective; In other words, that there was
change. When the little creature was blind
folded it assumed the same tint as at night,
and did not change when placed upon the
most striking colors showing that the eye
was the involuntary medium by which the
different tintS We're obtained. The act of
adaptation is perfectly involuntary,
made without the knowledge of the animal,
being the effect which certain colors have
upon the pigment cells of the animal. At
least this IS the generally accepted explana-
ton, and the experiments which have been
made with blind animals seem to show be-
yond question that the eye is the medium.
These peculiar changes, which are so well
known in fishes and reptiles, can be under
stood by glancing at the pigment cells of "A
frog. The skin is seen to consist of two
portions, the cults and ep1derm1s, the latter
apparently being made up of cells. The
CUTS has large cavities among the nerves,
which are commonly filled with pigment
and are very sensitive, contracting and eX
panding in a remarkable way. The pigment
cells are called chromatophores, and vary
parts of each animal, and may be red,
brown, green, yellow, black or various
shades. The color of the chromatophores
appears to change during contraction or
expansion, and constitutes most compli-
Gated and delicate study. Thus, in little
fish (Gobius RuthensparrD Heincke, the
German naturalist, while watching its yell
low pigment cells, saw them gradually ex-
pand and become black.
These cells are distributed all over the
body with more or less regularity, and upon
their contraction and expansion depends
the prevailing color of the animal. Thus,
If the pigment cells or chromatophores ex-
pand, the prevailing color will become
black, and the very light spots In the ami
NAL dull. On the other hand, IL they con-
tract, "a reverse effect obtains. Exactly how
these wonderful changes in all animals
which adapt themselves to their environ
ments are produced is not known. but 1t is
assumed that certain colors through the
medium of the optic nerve produce contrac-
tion or expansion, and the result is a pro-
tective tint or one which assimilates that
upon which the animal is resting. The eye
receives the stimulus or impression, which
passes from the optic nerves 70 the sympa-
thetic nerve. so reaching the various series
of chromatophores.