The sun., 1900-12-23


u,s, In almos, every cass thsy vary greatly
and wis, IL sull more important. tha,
,,.rv organ and every sppendase vanea In.
dctendently and 90 = large amount, Sons
n, the test known of th~e facts ~ variation
arc ndduccd IN my Darwinisrn.' and ara
uu.,ra,cd hy numerous diagrams. and
,uc,. more et,cnpive SERIES havo sinos b~cn
.,smincd always with Tho same general
,c-,t Ivy large variability IL meant n
va-a'ion ~ from 10 20 rs per cont. on each
,Ie - Tho mean sl,~. this amount NJ varia =
,lor occurring In NJ least Q or 10 per cent ~
Tho whole number ~ individuals. AMI In
ivory organ or part as yet examined. eI-
tsrril or internal.
Now. ~ the wedding -out process Ia 40
severe only from one In ten 10 ono In n
hun lrcd NJ those born surviving to produce
Young tho above proportion ~ variations
aruris ample scope for the selection ~ any
variation needed In order to modify the
species - as To bring II into harmony with
now or changing conditions. And this
will loo the moro etsy and certain II we
consider how slowly land surfaces and
climates undergo permanent changes; and
thcse are certainly IN" kind OF changes
that initiate and compel alterations. first.
perhaps. in the distribution and afterward
In the structure and habits OF species. IL
follows, therefore. "a an absolutely necessary
conclusion from the facts. II natural selec-
ton can and does keep each continually
VARYING species In close adaptation TO an
unchantng environment. that IL preserves
the fxity Of its mean or average condition,
and almost every objector admits this.
Then, given a slowly changing environment.
the same power must inevitably bring about
whatever corresponding change Is needed
for the well-being and permanent survival
o. the various species which are subjected
70 those changed conditions.
Srace will not permit further considera-
ton OF the objections and difficulties al
legged by critics OF the theory. All Of these
have | believe, been fully answered either
by Darwin or myself. many OF the most
recent having been discussed In review
articles which have lately been published
In a collected form under the title Studies.
Scientific and Social" Suffice II to say
here that this theory OF natural selection
meaning the elimination OF the least 1T
and therefore the ultimate survival OF
the fttest has furnished a rational and
precise explanation OF the means OF adapta-
don Of all existing organisms to their con-
dtions, and therefore OF their transforms
ton from the series OF distinct but allied
snoces which occupied the earth at some
preceding epoch In this sense II has
actually demonstrated the origin OF
speces,' and by carrying back this process
step by step into earlier and earlier geo.
logical times, we are able mentally TO follow
ou. the evolution Of all forms Of life from
one or a few primordial forms. Natural
selection has thus supplied that motive
power Of change and adaptation that was
wanting in all earlier attempts at eIplana-
ton. and this has led to It's very general ac-
ceptance both by naturalists and by the
great majority Of thinkers and men OF
science.
The brief sketch now given Of the progress
OF human thought on the questions OF the
fact and the mode OF the evolution Of the
material universe indicates how great has
been the progress during the nineteenth
as compared with all preceding centuries.
Although the philosophical writer's Of
classical times obtained few gllmpses
Of the action OF Inv In nature regulating
its successive changes, nothing salts
factory could be effected till the actual
facts had been better ascertained by the
whole body OF workers who, during the last
Ave centuries. have penetrated ever more
and more deeply into natures mysteries
and laws. BY their labors we became
possessed OF such body Of carefully OBJ
served facts that toward the end Of the
last century such thinkers as Laplace and
Hutton were enabled to give us the f1rst
rIdiments Of theories Of evolution as ap-
crust, both OF which have been greatly
developed and rendered more secure dur
Ing the century now passing away.
In like manner Button and Goethe may
be said TO have started the idea Of organic
evolution, more systematically treated a
little later by Lamarck. but still without
any discovery Of laws adequate 10 produce
the results we see everywhere In nature.
TIE subject then langished till. after
twenty years OF observation and research,
Charles Darwin produced work which at
once satisfied many thinkers that tho long
desired clue had been discovered. lts
acceptance by almost the whole scientific
world soon followed: II threw new light
on almost every branch Of research. and
It will probably take its place in the opinion
in future generations. "a the crownins
achievement Of the nineteenth century.