The times., 1900-12-23

/ this process of determination one OF na-
| tural seicction'-that Is by this process
nature weeds out the weak. the unhealthy,
| the unadapted, the imperfect In any way.
| OF course. what may he called chance CT
accident produces many deaths OF indi-
! vlduals otherwise well fitted to live. but
| IL we think of the process going on day
| by day and year by year till only one IN
a hundred OF those born In given area
| is left alive. 1t Is impossible to suppose
that the one which has passed through all
the dangers and risks which have been
T, fatal to- say. his ninety nine relations
| was not in all the faculties and qualities
| essential to the continuance Of the race.
| decidedly better organized than the bulk
! of those which suecumbed. Herbert Spen-
Ger calls the process the Survival CT the
fittest" and though the term NAV not be
4 strictly accurate in the case OF any one
] species in any one year. yet when We
| consider that the struggle is going on
| every year. during the whole duration OF
1 each species. we cannot doubt that. en-
the whole, and in the long run those
which survive are among The fittest. The
| struggle is so severe SO ineessant that
the smallest defect in any sense organ,
any physical weakness, any imperfection
in constitution, will almost certainly. at
one time or another. be fatal.
This continual wedding out OF the less
fit, in every generation. and with exeep-
tional severity in recurring adverse sea-
sons, will produce two distinct effects,
which require to be clearly distinguish
ed The first is the preservation of each
| species in the highest state Of adaptation
| to the conditions OF its existence, and
| therefore, SO long as those conditions
| remain unchanged, the effect OF natural
| selection Is to keep each weil-adapted
species also unchanged. The second ef-
feet is produced whenever the conditions
vary when, taking advantage OF the ye-
riations continually occurring in all WE'LL
adapted and therefore pepulous species,
the same process will slowly but surely
| bring about complete adaptation to the
new conditions. And here another fact
the normal variability of all popuious
or dominant species, which is seldom re-
allied except by those who have largely
| AMI minuteIy compared the individuals
OF many species in a state Of nature
comes into play. There are some writer's
! who admit all the preceding facts and
reasoning SO far as the action OF natural
selection In wedding out the unnt ana
thus keeping every species in the high
est state of efficiency Is concerned, but
who deny that it can modify them in such
way as to adapt them to new condi-
tions, because they alleged that the
right variations will not always occur
at the right time" This seems strong
and real objection to many OF their read
ers, but to those who have studied the
variability Of species in nature, 1t is
mere verbal difficulty dependent on ig-
norance Of the actual facts brief
statement of the facts must therefore be
given.
OF late years, and chiefly since Dar-
| wins works were written. the variable
ity of animals and plants in state of IA
! ture has been carefully studied. by actual
comparison and measurement OF scores.
hundreds and even thousands of fnGiyid-
| uals OF many common, that is, abundant
! and widely distributed species: and il is
found that in almost every case they vary
greatly. and, what is still more important,
that every organ and every appeudage
| varies independently and to large
amount Some OF the best known Of these
| facts of variation are adGaced IN my
| ''Darwinism" and are illustrated by num-
| erous diagrams. and much more extensive
series have since been examined, always
with the same general result. By large
variability is meant a variation OF from
10 TO s5 per cent on each side OF the mean
size this amount OF variation occurring
in at least or 10 per cent Of the whole
number Of individuals. and In every organ
or part as yet examined, external or in
ternal.
Now. as the weeding-out process is 20
| severe, only from one in ten to one in
hundred of those born surviving to Pro
duce young the above proportion OF va
Ration affords ample scope for the seiec-
ton of any variation needed in order to
ruodffy the species so as to bring 1t into
harmony with new or changing conditions.
And this will be the more easy and GER
tain il we consider how slowly land-sur-
faces and climates undergo permanent
changes: and these are certainly the kind
of changes that initiate and compel al
teTations, first, perhaps, in the distribu-
tion and aftsrward in the structure and
habits of species. 1t fellows, therefore,
as an absolutely necessary conclusion
from the facts. if natural selection
can and de.s keep each continually vary
ing species in close adaptation to an
/ u1cbaEgi1g environment, that 1t pre-
serves the fxity of its mean or average
condition, aad almost every ebjeetor ad-
mits this. Then. given a slowly chang
ing environment, the same power must
inevitably bring about whatever corre-
spending change is needed fer the we'll
beiag and perraa Eent survival OF the va
rious species which are subjected to those
changed conditions.
Space will not permit further consid-
| Grafton of the objections and difficulties
| alleged by critics Of the theory. All OF
| these have, I believe, been fully an
swered either by Darwin or myself, many
of the most recent having been discussed
| in review articles which VIII shortly be
| published In a collected form under the
; title Studies, Scientific and Social SUI
fee IL to say here that this theory of nat
ural selectien-neaRl1g the elimination
OF the least fit and therefore the ultimate
| SURVIVAL of the fttest"-has furnished
a rational and precise explanation cf the
means OF adaptation of all existing or
| eanisfns TO their conditions. and there
| fore of their transformation from the
| series of distinct but allied species which
} | occupied the earth at some preceding
epoch In this sense it has actually dem
onstrated the "erigiR OF species" and, by
carrying back this process step by step
into earlier and earlier geological times,
| we are able mentally to follow out the
evolution of all FERNS of life from
one or few priulordia1 forms.
Natural selection has thus supplied that
motive power of change and adaptation
that was wanting IN all earlier attemp'
at explanation. and this has led to its
very general acceptance both by nat
uralists and by the great majority OF
| thinkers and men of science
The brief sketch now given OF the prog
ress of human Thought on the questions
Of the fact and the mode Of the evolu-
ton OF the material universe indicates
how great has been the progress during
the nineteenth as compared with all pre-
ceding centuries.
Although the philosophical writer's OF
| classical times obtained few glimpses
OF the action OF law in nature regulating
its successive changes, nothing satisfac-
tory could be effected till the actual facts
had been better ascertained by the whole
body OF workers who. during the last 1--WE
centuries. have penetrated ever more and
more deeply into natures mysteries and
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