The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1867-08-21
MIMIORY AMONG ANIMALS.

WAAmgeh hAmNmA hnAMaAhs
From Ue WesfnhlSter BeUtstO.
There is no more convincing proof Of the
truth Of comprehensive theory than its
mower of absorbing and finding place for new
facts and its capability of interpreting phe-
nomena which had been previously looked
upon as unaccountable anomalies. Il is thus
that the law of universal gravitation and the
undulatory theory of light have become esta-
blished and universally accepted by men of
science Fact after fact has been brought for
ward as being apparently inconsistent with
tbem. and one after another these very facts
have been shown to be the consequences of the
laws they were at first supposed to disprOve.
A false theory will never stand this test.
Tdvoncino knowledge brings to light whole
1,ronns of facts which it cannot deal with,
esnd its advocates steadily decrease in num-
hers notwithstanding the ability and scien-
t;fo ekiU with which it may have been sup
artod The great name of Edward Forbes
St5 not nrevept his theory of POLARITY in
tbe distribution of Organic Beings in Time, I"
from diving a natural death; but the most
striking illustration of the behavior of
false theory is to be found in the "Circular
and Ouinarian System" of classification pro-
pounded by MacLeay, and developed by
Swanson, with an amount of knowledge
and ingenuity that have rarely been sur
passed This theory was eminently attrac-
tive. both from its symmetry and complete
ness and from the interesting nature of the
varied analogies and atfnities which it brought
TO light and made use of. The series of Ma
turai History volumes in 'Lardner's Cabinet
Cyclopadia," in which Mr.. Swanson de-
veloped it in most departments of the animal
kingdom, made it widely known; and in fact
for long time these were the best and almost
the only popular textbooks for the rising
generation Of naturalists. 1t was favorably
received too by the older school, which
was perhaps rather an indication of its
nnsoundness. A considerable number of
well-knOwn naturalists either spoke APP
provingy of it, or advocated similar princi-
PIES and for good many years it was de-
cidedly in the ascendant. With such favor
able introduction, and with such talented ex-
ponents it must have become established if it
had had any germ of truth in it; yet it quite
died out in a few short years, its very exist
snee is now matter of history, and so rapid
was its fall that its talented creator, Swanson,
perhaps lived to be the last man who believed
in it.
Such is the course of false theory. That
of true one is very different as may be well
seen by the progress of opinion on the subject
Of Natural Selection. In less than eight years
''The Origin of Species has produced convic-
tiOn in the minds of majority of the most
eminent living men of science. New facts,
new problems, new difficulties as they arise
aro accepted, solved, or removed by this
theory; and its principles are illustrated by
the progress and conclusions OF every other
well established branch of human knowledge.
1t is the object of the present article to show
how it has recently been applied to connect
together and explain a variety of curious facts
which had long been considered as inexplica-
BILE anomalies.
Perhaps no principle has ever been an
nounced so fertile in results as that which Mr..
Darwin so earnestly impresses upon us, and
which is indeed necessary deduc ton from
the theory of Natural Selection-namely,
that none of the definite facts of organic
nature, no special organ, no characteristic
form or marking, no peculiarities of instinct
or Of habit, no relations between species or
between group of species, can exist, but
which must now be or once have been use
full to the individual or the races which
possess them. This great principle gives us
a clue which we can follow out in the study
Of many recondite phenomena, and leads
us to seek a meaning and purpose of some
definite character in minutie which we should
be otherwise almost sure to pass over as in
significant or unimportant.
The adaptation of the external coloring of
animals to their conditions of life has long
been recognized and has been imputed either
to an originally created specific popularity or
to the direct action of climate, soil, or food.
Where the former explanation has been ac
cepted, it has completely checked inquiry,
since we could never get any further than the
fact of the adaptation. There was nothing
more to be known about the matter. The
second explanation was soon found to be quite
inadequate to deal with all the varied phases
of the phenomena, and to be contradicted by
many well-known facts. For example, wild
rabbits are always of grey or brown tints
well suited for concealment among grass and
fern. But when these rabbits are dOmes-
ticated, without any change of climate or
food, they vary into white or black,
and these varieties may be multiplied to
any extent, forming white or black
races Exactly the same thing has oc-
CURED with pigeons; and in the case OF
rats and mice, the white variety has not been
shown to be at all dependent on alteration o
climate food, or other external conditions. Ii
many cases the wings of an insect not only
assume the exact tint Of the bark or leaf it is
accustomed to rest on but the form and vein
ing of the leaf or the exact rugosity of the
bark is initiated; and these detailed modiica
tions cannot be reasonably imputed to climate
or to food, since in many cases the species
does not feed on'the substance it resembles
and, when it does, no reasonable connection
can be shown to exist between the supposed
cause and the effect produced. 1t was re
served for the theory of Natural Selection Il
solve all these problems, and many other
which We're not at first supposed to be directly
connected with them. To make these latter
intelligible, it will be necessary to give
sketch of the whole series of phenomena whiel
may be classed under the head of useful o.
protective resemblances.
Concealment more or less complete is use
ful to many animals, and absolutely essen