the darwinian hypothesis-第3节

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ridicule；　and　in　the　present　case　the　logical　form　of　the　doctrine
stands　on　a　very　different　footing　from　its　substance。

If　species　have　really　arisen　by　the　operation　of　natural　conditions；　we
ought　to　be　able　to　find　those　conditions　now　at　work；　we　ought　to　be
able　to　discover　in　nature　some　power　adequate　to　modify　any　given　kind
of　animal　or　plant　in　such　a　manner　as　to　give　rise　to　another　kind；
which　would　be　admitted　by　naturalists　as　a　distinct　species。　　Lamarck
imagined　that　he　had　discovered　this　'vera　causa'　in　the　admitted　facts
that　some　organs　may　be　modified　by　exercise；　and　that　modifications；
once　produced；　are　capable　of　hereditary　transmission。　　It　does　not
seem　to　have　occurred　to　him　to　inquire　whether　there　is　any　reason　to
believe　that　there　are　any　limits　to　the　amount　of　modification
producible；　or　to　ask　how　long　an　animal　is　likely　to　endeavour　to
gratify　an　impossible　desire。　　The　bird；　in　our　example；　would　surely
have　renounced　fish　dinners　long　before　it　had　produced　the　least　effect
on　leg　or　neck。

Since　Lamarck's　time；　almost　all　competent　naturalists　have　left
speculations　on　the　origin　of　species　to　such　dreamers　as　the　author　of
the　'Vestiges'；　by　whose　well…intentioned　efforts　the　Lamarckian　theory
received　its　final　condemnation　in　the　minds　of　all　sound　thinkers。
Notwithstanding　this　silence；　however；　the　transmutation　theory；　as　it
has　been　called；　has　been　a　〃skeleton　in　the　closet〃　to　many　an　honest
zoologist　and　botanist　who　had　a　soul　above　the　mere　naming　of　dried
plants　and　skins。　　Surely；　has　such　an　one　thought；　nature　is　a　mighty
and　consistent　whole；　and　the　providential　order　established　in　the
world　of　life　must；　if　we　could　only　see　it　rightly；　be　consistent　with
that　dominant　over　the　multiform　shapes　of　brute　matter。　　But　what　is
the　history　of　astronomy；　of　all　the　branches　of　physics；　of　chemistry；
of　medicine；　but　a　narration　of　the　steps　by　which　the　human　mind　has
been　compelled；　often　sorely　against　its　will；　to　recognize　the
operation　of　secondary　causes　in　events　where　ignorance　beheld　an
immediate　intervention　of　a　higher　power？　　And　when　we　know　that　living
things　are　formed　of　the　same　elements　as　the　inorganic　world；　that　they
act　and　react　upon　it；　bound　by　a　thousand　ties　of　natural　piety；　is　it
probable；　nay　is　it　possible；　that　they；　and　they　alone；　should　have　no
order　in　their　seeming　disorder；　no　unity　in　their　seeming
multiplicity；　should　suffer　no　explanation　by　the　discovery　of　some
central　and　sublime　law　of　mutual　connexion？

Questions　of　this　kind　have　assuredly　often　arisen；　but　it　might　have
been　long　before　they　received　such　expression　as　would　have　commanded
the　respect　and　attention　of　the　scientific　world；　had　it　not　been　for
the　publication　of　the　work　which　prompted　this　article。　　Its　author；
Mr。　Darwin；　inheritor　of　a　once　celebrated　name；　won　his　spurs　in
science　when　most　of　those　now　distinguished　were　young　men；　and　has
for　the　last　20　years　held　a　place　in　the　front　ranks　of　British
philosophers。　　After　a　circumnavigatory　voyage；　undertaken　solely　for
the　love　of　his　science；　Mr。　Darwin　published　a　series　of　researches
which　at　once　arrested　the　attention　of　naturalists　and　geologists；　his
generalizations　have　since　received　ample　confirmation；　and　now　command
universal　assent；　nor　is　it　questionable　that　they　have　had　the　most
important　influence　on　the　progress　of　science。　　More　recently　Mr。
Darwin；　with　a　versatility　which　is　among　the　rarest　of　gifts；　turned
his　attention　to　a　most　difficult　question　of　zoology　and　minute
anatomy；　and　no　living　naturalist　and　anatomist　has　published　a　better
monograph　than　that　which　resulted　from　his　labours。　　Such　a　man；　at
all　events；　has　not　entered　the　sanctuary　with　unwashed　hands；　and　when
he　lays　before　us　the　results　of　20　years'　investigation　and　reflection
we　must　listen　even　though　we　be　disposed　to　strike。　　But；　in　reading
his　work　it　must　be　confessed　that　the　attention　which　might　at　first
be　dutifully；　soon　becomes　willingly；　given；　so　clear　is　the　author's
thought；　so　outspoken　his　conviction；　so　honest　and　fair　the　candid
expression　of　his　doubts。　　Those　who　would　judge　the　book　must　read　it；
we　shall　endeavour　only　to　make　its　line　of　argument　and　its
philosophical　position　intelligible　to　the　general　reader　in　our　own
way。

The　Baker…street　Bazaar　has　just　been　exhibiting　its　familiar　annual
spectacle。　Straight…backed；　small…headed；　big…barrelled　oxen；　as
dissimilar　from　any　wild　species　as　can　well　be　imagined；　contended　for
attention　and　praise　with　sheep　of　half…a…dozen　different　breeds　and
styes　of　bloated　preposterous　pigs；　no　more　like　a　wild　boar　or　sow　than
a　city　alderman　is　like　an　ourang…outang。　　The　cattle　show　has　been；
and　perhaps　may　again　be；　succeeded　by　a　poultry　show；　of　whose　crowing
and　clucking　prodigies　it　can　only　be　certainly　predicated　that　they
will　be　very　unlike　the　aboriginal　'Phasianus　gallus'。　　If　the　seeker
after　animal　anomalies　is　not　satisfied；　a　turn　or　two　in　Seven　Dials
will　convince　him　that　the　breeds　of　pigeons　are　quite　as　extraordinary
and　unlike　one　another　and　their　parent　stock；　while　the　Horticultural
Society　will　provide　him　with　any　number　of　corresponding　vegetable
aberrations　from　nature's　types。　　He　will　learn　with　no　little　surprise；
too；　in　the　course　of　his　travels；　that　the　proprietors　and　producers
of　these　animal　and　vegetable　anomalies　regard　them　as　distinct
species；　with　a　firm　belief；　the　strength　of　which　is　exactly
proportioned　to　their　ignorance　of　scientific　biology；　and　which　is　the
more　remarkable　as　they　are　all　proud　of　their　skill　in　'originating'
such　〃species。〃

On　careful　inquiry　it　is　found　that　all　these；　and　the　many　other
artificial　breeds　or　races　of　animals　and　plants；　have　been　produced　by
one　method。　　The　breederand　a　skilful　one　must　be　a　person　of　much
sagacity　and　natural　or　acquired　perceptive　facultynotes　some　slight
difference；　arising　he　knows　not　how；　in　some　individuals　of　his　stock。
If　he　wish　to　perpetuate　the　difference；　to　form　a　breed　with　the
peculiarity　in　question　strongly　marked；　he　selects　such　male　and
female　individuals　as　exhibit　the　desired　character；　and　breeds　from
them。　　Their　offspring　are　then　carefully　examined；　and　those　which
exhibit　the　peculiarity　the　most　distinctly　are　selected　for　breeding；
and　this　operation　is　repeated　until　the　desired　amount　of　divergence
from　the　primitive　stock　is　reached。　　It　is　then　found　that　by
continuing　the　process　of　selectionalways　breeding；　that　is；　from
well…marked　forms；　and　allowing　no　impure　crosses　to　interfere；a　race
may　be　formed；　the　tendency　of　which　to　reproduce　itself　is　exceedingly
strong；　nor　is　the　limit　to　the　amount　of　divergence　which　may　be　thus
produced　known；　but　one　thing　is　certain；　that；　if　certain　breeds　of
dogs；　or　of　pigeons；　or　of　horses；　were　known　only　in　a　fossil　state；
no　naturalist　would　hesitate　in　regarding　them　as　distinct　species。

But；　in　all　these　cases　we　have　'human　interference'。　　Without　the
breeder　there　would　be　no　selection；　and　without　the　selection　no
race。　　Before　admitting　the　possibility　of　natural　species　having
originated　in　any　similar　way；　it　must　be　proved　that　there　is　in　nature
some　power　which　takes　the　place　of　man；　and　performs　a　selection　'sua
sponte'。　　It　is　the　claim　of　Mr。　　Darwin　that　he　professes　to　have
discovered　the　existence　and　the　'modus　operandi'　of　this　natural
selection；　as　he　terms　it；　and；　if　he　be　right；　the　process　is　perfectly
simple　and　comprehensible；　and　irresistibly　deducible　from　very
familiar　but　well　nigh　forgotten　facts。

Who；　for　instance；　has　duly　reflected　upon　all　the　consequences　of　the
marvellous　struggle　for　existence　which　is　daily　and　hourly　going　on
among　living　beings？　　Not　only　does　every　animal　live　at　the　expense　of
some　other　animal　or　plant；　but　the　very　plants　are　at　war。　　The　ground
is　full　of　seeds　that　cannot　rise　into　seedlings；　the　seedlings　rob　one
another　of　air；　light　and　water；　the　strongest　robber　winning　the　day；
and　extinguishing　his　competitors。　　Year　after　year；　the　wild　animals
with　which　man　never　interferes　are；　on　the　average；　neither　more　nor
less　numerous　than　they　were；　and　yet　we　know　that　the　annual　produce　of
every　pair　is　from　one　to　perhaps　a　million　young；so　that　it　is
mathematically　certain　that；　on　the　average；　as　many　are　killed　by
natural　causes　as　are　born　every　year；　and　those　only　escape　which
happen　to　be　a　little　better　fitted　to　resist　destruction　than　those
which　die。　　The　individuals　of　a　species　are　like　the　crew　of　a
foundered　ship；　and　none　but　good　swimmers　have　a　chance　of　reaching
the　land。

Such　being　unquestionably　the　necessary　conditions　under　which　living
creatures　exist；　Mr。　　Darwin　discovers　in　them　the　instrument　of
natural　selection。　　Suppose　that　in　the　midst　of　this　incessant
competition　some　individuals　of　a　species　（A）　present　accidental
variations　which　happen　to　fit　them　a　little　better　than　their　fellows
for　the　struggle　in　which　they　are　engaged；　then　the　chances　are　in
favour；　not　only　of　these　individuals　being　better　nourished　t