下载辰思小说免费APP
Eachorganasitisdeveloped，serves，byitsactionsandreactionsonthe
rest，toinitiatenewcomplexities。Thefirstpulsationsofthefoetalheart
mustsimultaneouslyaidtheunfoldingofeverypart。Thegrowthofeachtissue，
bytakingfromthebloodspecialproportionsofelements，mustmodifythe
constitutionoftheblood;andsomustmodifythenutritionofalltheother
tissues。Thedistributiveactions，implyingastheydoacertainwaste，necessitate
anadditiontothebloodofeffetematters，whichmustinfluencetherest
ofthesystem，andperhaps，assomethink，initiatetheformationofexcretory
organs。Thenervousconnexionsestablishedamongthevisceramustfurther
multiplytheirmutualinfluences。Andsoisitwitheverymodificationof
structure——everyadditionalpartandeveryalterationintheratiosof
parts。Proofofamoredirectkindisfurnishedbythefact，thatthesame
germmaybeevolvedintodifferentformsaccordingtocircumstances。Thus，
duringitsearlieststages，everygermissexless——originateseithermale
orfemaleasthebalanceofforcesactingonitdetermines。Again，there
isthefamiliartruththatthelarvaofaworking—beewilldevelopintoa
queen—beeif，beforeacertainperiod，itisfedafteramannerlikethat
inwhichthelarvaeofqueen—beesarefed。Thenthereisthestillmorestriking
evidencefurnishedbyantsandtermites。Riley，Grassi，Haviland，andHart，
haveshownthatdifferencesofnutritionnotonlyoriginatethedifferences
betweenmalesandfemalesbutalsothedifferenttraitsofsolders，workers，
andnurses。*<*SeePrinciplesofBiology，Vol。I，pp。680—8。>Varying
degreeofnutrition，afterinitiatingtheunlikenessofsex，thendetermines
theunlikenessesofexternalorganspossessedbythevariousclassesofsexless
individuals。Nextcomestheevidence，stillmoredirectlyrelevant，supplied
bytheeffectsofcastration。Iftheremovalofcertainorganspreventsthe
developmentofcertainotherorgansinremotepartsofthesystem——inman
thevocalstructures，thebeard，sometraitsofgeneralform，someinstincts
andothermentalcharacters——thenitisclearthatwheretheseorganshave
notbeenremoved，thepresenceofthemdeterminestheoccurrenceofthese
variouschangesofdevelopment，anddoubtlessmanyminoroneswhichareunobtrusive。
Herethefactthatonecauseproducesmanyeffectsinthecourseoforganic
evolutionisindisputable。Doubtlessweare，andmustevercontinue，unable
toconceivethosemysteriouspropertieswhichmakethegermwhensubject
tofitinfluencesundergothespecialchangesinitiating，andmainlyconstituting，
thetransformationsofanunfoldingorganism;thoughwemayconsistently
supposethattheyrepresentaninfiniteseriesofinheritedmodifications
consequentontheinstabilityofthehomogeneous，themultiplicationofeffects，
andonefurtherfactorstilltobesetforth。Allherecontendedisthat，
givenagermpossessingthesemysteriousproperties，theevolutionofan
organismfromitdepends，inpart，onthatmultiplicationofeffectswhich
wehaveseentobeonecauseofevolutioningeneral，sofaraswehaveyettracedit。When，leavingthedevelopmentofsingleplantsandanimals，wepassto
thatoftheEarth\'sFloraandFauna，thecourseoftheargumentagainbecomes
clearandsimple。Though，asbeforeadmitted，thefragmentaryfactsPalaeontology
hasaccumulated，donotclearlywarrantusinsayingthat，inthelapseof
geologictime，therehavebeenevolvedmoreheterogeneousorganisms，and
moreheterogeneousassemblagesoforganisms;yetweshallnowseethatthere
musteverhavebeenatendencytowardstheseresults。Weshallfindthat
theproductionofmanyeffectsbyonecause，which，asalreadyshown，has
beenallalongincreasingthephysicalheterogeneityoftheEarth，hasfurther
necessitatedanincreasingheterogeneityofitsinhabitingorganisms，individuallyandcollectively。Anillustrationwillmakethisclear。Supposethatbyupheavals，occurring，astheyareknowntodo，atlong
intervals，theEastIndianArchipelagowereraisedintoacontinent，and
achainofmountainsformedalongtheaxisofelevation。Bythefirstof
theseupheavals，theplantsandanimalsofBorneo，Sumatra，NewGuinea，and
therest，wouldbesubjectedtoslightly—modifiedsetsofconditions。The
climateofeachwouldbealteredintemperature，inhumidity，andinits
periodicalvariations，whilethelocaldifferenceswouldbemultiplied。The
modificationswouldeffect，perhapsinappreciably，theentireFloraandFauna
oftheregion。Thechangeoflevelwouldentailadditionalmodifications，
varyingindifferentspecies，andalsoindifferentmembersofthesamespecies，
accordingtotheirdistancefromtheaxisofelevation。Plantsgrowingonly
onthesea—shoreinspeciallocalities，mightbecomeextinct。Others，living
onlyinswampsofacertainhumidity，would，iftheysurvivedatall，probably
undergovisiblechangesofappearance。Whilemoremarkedalterationswould
occurinsomeoftheplantsthatspreadoverthelandsnewlyraisedoutof
thewater。Theanimalsandinsectslivingonthesemodifiedplants，would
themselvesbeinsomedegreemodifiedbychangesoffood，aswellasbychanges
ofclimate;andthemodificationswouldbemoremarkedwhere，fromthedwindling
ordisappearanceofonekindofplant，analliedkindwaseaten。Inthelapse
ofthemanygenerationsarisingbeforethenextupheaval，thesensibleor
insensiblealterationsthusproducedineachspecies，wouldbecomeorganized
——inalltheraceswhichsurvivedtherewouldbemoreorlessadaptation
tothenewconditions。Thenextupheavalwouldsuperinducefurtherorganic
changes，implyingwiderdivergencesfromtheprimaryforms;andsorepeatedly。
Now，however，observethatthisrevolutionwouldnotbeasubstitutionof
athousandmodifiedspeciesforthethousandoriginalspecies;butinplace
ofthethousandoriginalspeciestherewouldariseseveralthousandspecies，
orvarieties，orchangedforms。Eachspeciesbeingdistributedoveranarea
ofsomeextent，andtendingcontinuallytocolonizethenewareaexposed，
itsdifferentmemberswouldbesubjecttodifferentsetsofchanges。Plants
andanimalsmigratingtowardstheequatorwouldnotbeaffectedinthesame
waywithothersmigratingfromit。Thosewhichspreadtowardsthenewshores，
wouldundergochangesunlikethechangesundergonebythosewhichspread
intothemountains。Thus，eachoriginalraceoforganismswouldbecomethe
rootfromwhichdivergedseveralraces，differingmoreorlessfromitand
fromoneanother;andwhilesomeofthesemightsubsequentlydisappear，probably
morethanonewouldsurviveintothenextgeologicperiod。Notonlywould
certainmodificationsbethuscausedbychangesofphysicalconditionsand
food，butalso，insomecases，othermodificationscausedbychangesofhabit。
Thefaunaofeachisland，peopling，stepbystep，thenewly—raisedtracts，
wouldeventuallycomeincontactwiththefaunasofotherislands;andsome
membersoftheseotherfaunaswouldbeunlikeanycreaturesbeforeseen。
Herbivoresmeetingwithnewbeastsofpreywould，insomecases，beledinto
modesofdefenceorescapedifferingfromthosepreviouslyused;andsimultaneously
thebeastsofpreywouldmodifytheirmodesofpursuitandattack。Weknow
thatwhencircumstancesdemandit，suchchangesofhabitdotakeplacein
animals;andweknowthatifthenewhabitsbecomethedominantones，they
musteventuallyinsomedegreealtertheorganization。Note，now，afurther
consequence。Theremustarisenotsimplyatendencytowardsthedifferentiation
ofeachraceoforganismsintoseveralraces;butalsoatendencytothe
occasionalproductionofasomewhathigherorganism。Takeninthemass，these
divergentvarieties，whichhavebeencausedbyfreshphysicalconditions
andhabitsoflife，willexhibitalterationsquiteindefiniteinkindand
degree，andalterationsthatdonotnecessarilyconstituteanadvance。Probably
inmostcasesthemodifiedtypewillbenotappreciablymoreheterogeneous
thantheoriginalone。Butitmustnowandthenoccurthatsomedivision
ofaspecies，fallingintocircumstanceswhichgiveitrathermorecomplex
experiences，anddemandactionssomewhatmoreinvolved，willhavecertain
ofitsorgansfurtherdifferentiatedinproportionatelysmalldegrees——
willbecomeslightlymoreheterogeneous。Hence，therewillfromtimetotime
ariseanincreasedheterogeneitybothoftheEarth\'sfloraandfauna，and
ofindividualracesincludedinthem。Omittingdetailedexplanations，and
allowingforqualificationswhichcannotherebespecified，itissufficiently
clearthatgeologicalmutationshaveallalongtendedtocomplicatetheforms
oflife，whetherregardedseparatelyorcollectivelyThatmultiplication
ofeffectswhichhasbeenapart—causeofthetransformationoftheEarth\'s
crustfromthesimpleintothecomplex，hassimultaneouslyledtoaparallel
transformationoftheLifeuponitssurface。（*）
firstpublishedintheWestminsterReviewinApril，1857，beenwritten
aftertheappearanceofMr。Darwin\'sworkonTheOriginofSpecies，
insteadofbefore，itwoulddoubtlesshavebeenotherwiseexpressed。Reference
wouldhavebeenmadetotheprocessof"naturalselection，"as
greatlyfacilitatingthedifferentiationsdescribed。Asitis，however，I
prefertoletthepassagestandinitsoriginalshape;partlybecauseit
seemstomethatthesesuccessivechangesofconditionswouldproducedivergent
varietiesorspecies，apartfromtheinfluenceof"naturalselection"
（thoughinlessnumerouswaysaswellaslessrapidly）;andpartlybecause
Iconceivethatintheabsenceofthesesuccessivechangesofconditions，
"naturalselection"wouldeffectcomparativelylittle。Letmeadd
thatthoughthesepositionsarenotenunciatedinTheOriginofSpecies，
yetacommonfriendgivesmereasontothinkthatMr。Darwinwouldcoincideinthem。Thedeductionheredrawnfromtheestablishedtruthsofgeologyandthe
generallawsoflife，gainsimmenselyinweightonfindingittobeinharmony
withaninductiondrawnfromdirectexperience。Justthatdivergenceofmany
racesfromonerace，abovedescribedascontinuallyoccurringduringgeologic
time，weknowtohaveoccurredduringthepre—historicandhistoricperiods，
inmananddomesticanimals。Andjustthatmultiplicationofeffectswhich
weconcludedmusthavebeeninstrumentaltothefirst，weseehasingreat
measurewroughtthelast。Singlecauses，asfamine，pressureofpopulation，
war，haveperiodicallyledtofurtherdispersionsofmenandofdependent
creatures:eachsuchdispersioninitiatingnewmodifications，newvarieties。
Whetherallthehumanracesbeorbenotderivedfromonestock，philology
showsthatinmanycasesagroupofraces，noweasilydistinguishablefrom
oneanother，wasoriginallyonerace——thatthediffusionofoneraceinto
differentregionsandconditionsofexistencehasproducedmanyalteredforms
ofit。Similarlywithdomesticanimals。Thoughinsomecases，asthatof
dogs，communityoforiginwillperhapsbedisputed，yetinothercases，as
thatofthesheeporthecattleofourowncountry，itwillnotbequestioned
thatlocaldifferencesofclimate，food，andtreatment，havetransformed
oneoriginalbreedintomanybreeds，nowbecomesofardistinctastoproduce
unstablehybrids。Moreover，throughthecomplicationofeffectsflowingfrom
singlecauses，weherefind，whatwebeforeinferred，notonlyanincrease
ofgeneralheterogeneity，butalsoofspecialheterogeneity。Whileofthe
divergentdivisionsandsubdivisionsofthehumanrace，manyhaveundergone
changesnotconstitutinganadvance;othershavebecomemoreheterogeneous。
ThecivilizedEuropeandepartsmorewidelyfromthemammalianarchetypethandoestheAustralian。§160。Asense—impressiondoesnotexpenditselfinarousingsome
singlestateofconsciousness;butthestateofconsciousnessarousedis
madeupofvariousrepresentedsensationsconnectedbyco—existenceorsequence
withthepresentedsensation。Andthat，inproportionasthegradeofintelligence
ishigh，thenumberofideassuggestedisgreat，maybereadilyinferred。
Letus，however，lookattheproofthathere，too，eachchangeistheparent
ofmanychangesandthatthemultiplicationincreasesinproportionastheareaaffectediscomplex。Weresomehithertounknownbird，drivenbystressofweatherfromthe
remotenorth，tomakeitsappearanceonourshores，itwouldexcitenospeculation
inthesheeporcattleamidwhichitalighted:aperceptionofitasacreature
likethoseconstantlyflyingabout，wouldbethesoleinterruptionofthat
dullcurrentofconsciousnesswhichaccompaniesgrazingandrumination。The
cowherd，bywhomwemaysupposetheexhaustedbirdtobepresentlycaught，
wouldprobablygazeatitwithsomeslightcuriosity，asbeingunlikeany
hehadbeforeseenwouldnoteitsmostconspicuousmarkings，andvaguely
ponderonthequestions，whereitcamefrom，andhowitcame。Bythesight
ofit，thevillagebird—stufferwouldhavesuggestedtohimsundryforms
towhichitborealittleresemblance;wouldreceivefromitmorenumerous
andmorespecificimpressionsrespectingstructureandplumage;wouldbe
remindedofotherbirdsbroughtbystormsfromforeignparts;wouldtell
whofoundthem，whostuffedthem，whoboughtthem。Supposingtheunknown
birdtakentoanaturalistoftheoldschool，interestedonlyinexternals，
（oneofthosedescribedbyEdwardForbes，asexamininganimalsasthough
theywereskinsfilledwithstraw，）itwouldexciteinhimamoreinvolved
seriesofmentalchanges。Therewouldbeanelaborateexaminationofthe
feathers，anotingofalltheirtechnicaldistinctions，withareduction
oftheseperceptionstocertainequivalentwrittensymbols;reasonsforreferring
thenewformtoaparticularfamilyorder，andgenuswouldbesoughtout
andwrittendown;communicationswiththesecretaryofsomesocietyoreditor
ofsomejournal，wouldfollow;andprobablytherewouldbenotafewthoughts
abouttheadditionoftheiitothedescriber\'sname，toformthenameof
thespecies。Lastly，inthecomparativeanatomistsuchanewspecies，should
ithaveanymarkedinternalpeculiarity，mightproduceadditionalsetsof
changes——mightsuggestmodifiedviewsrespectingtherelationshipsofthe
divisiontowhichitbelonged;or，perhaps，alterhisconceptionsofthe
homologiesanddevelopmentsofcertainorgans;andtheconclusionsdrawn
mightpossiblyenteraselementsintostillwiderinquiriesconcerningtheoriginoforganicforms。Fromideasletusturntoemotions。Inayoungchild，afather\'sanger
produceslittleelsethanvaguefear——asenseofimpendingevil，taking
variousshapesofphysicalsufferingordeprivationofpleasures。Inelder
childrenthesameharshwordswillarouseadditionalfeelings:sometimes
asenseofshame，ofpenitence，orofsorrowforhavingoffended;atother
times，asenseofinjusticeandaconsequentanger。Inthewife，yetafurther
rangeoffeelingsmaycomeintoexistence——perhapswoundedaffection，perhaps
self—pityforill—usage，perhapscontemptforgroundlessirritability，perhaps
sympathyforsomesufferingwhichtheirritabilityindicates，perhapsanxiety
aboutanunknownmisfortunewhichshethinkshasproducedit。Norarewe
withoutevidencethatamongadults，thelikedifferencesofdevelopmentare
accompaniedbylikedifferencesinthenumberofemotionsaroused，incombination
orrapidsuccession:thelowernaturesbeingcharacterizedbythatimpulsiveness
whichresultsfromtheuncontrolledactionofafewfeelings;andthehigher
naturesbeingcharacterizedbythesimultaneousactionofmanysecondaryfeelings，modifyingthosefirstawakened。Perhapsitwillbeobjectedthattheillustrationsheregiven，aredrawn
fromthefunctionalchangesofthenervoussystem，notfromitsstructural
changes;andthatwhatisprovedamongthefirstdoesnotnecessarilyhold
amongthelast。Thismustbeadmitted。Those，however，whorecognizethe
truththatthestructuralchangesaretheslowlyaccumulatedresultsofthe
functionalchanges，willreadilydrawthecorollarythatapart—causeof
theevolutionofthenervoussystem，asofotherevolution，isthismultiplicationofeffectswhichbecomesevergreaterasthedevelopmentbecomeshigher。§161。IftheadvanceofMantowardsgreaterheterogeneity，inboth
bodyandmind，isinparttraceabletotheproductionofmanyeffectsby
onecause，stillmoreclearlymaytheadvanceofSocietytowardsgreaterheterogeneitybesoexplained。Considerthegrowthofindustrialorganization。Whensomeindividualof
atribedisplaysunusualaptitudeformakingweapons，whichwerebeforemade
byeachmanforhimself，therearisesatendencytowardsthedifferentiation
ofthatindividualintoamakerofweapons。Hiscompanions，warriorsand
huntersallofthem，severallywishingtohavethebestweaponsthatcan
bemade，arecertaintoofferstronginducementstothisskilledindividual
tomakeweaponsforthem。He，ontheotherhand，havingbothanunusualfaculty，
andanunusualliking，formakingweapons（capacityanddesirebeingcommonly
associated），ispredisposedtofulfilthesecommissionsontheofferofadequate
rewards:especiallyashisloveofdistinctionisalsogratified。Thisfirst
specializationoffunction，oncecommenced，tendsevertobecomemoredecided。
Onthesideoftheweapon—maker，continuedpracticegivesincreasedskill。
Onthesideofhisclients，cessationofpracticeentailsdecreasedskill。
Thusthissocialmovementtendstobecomemoredecidedinthedirectionin
whichitwasfirstsetup;andtheincipientheterogeneityis，ontheaverageofcases，likelytobecomepermanentforthatgeneration，ifnolonger。Suchadifferentiationhasatendencytoinitiateotherdifferentiations。
Theadvancedescribedimpliestheintroductionofbarter。Themakerofweapons
hastobepaidinsuchotherarticlesasheagreestotake。Nowhewillnot
habituallyexchangeforonekindofarticle。Hedoesnotwantmatsonly，
orskins，orfishing—gear。Hewantsallthese，andoneachoccasionwill
bargainfortheparticularthingshethenmostneeds。Whatfollows？Ifamong
themembersofthetribethereexistanyslightdifferencesofskillinthe
manufactureofthesevariousthingstheweapon—makerwilltakefromeach
onethethingwhichthatoneexcelsinmaking。Buthewhohasbarteredaway
hismatsorhisfishing—gear，mustmakeothermatsorfishing—gearforhimself;
andinsodoingmust，insomedegree，furtherdevelophisaptitude。Ifsuch
transactionsarerepeated，thesespecializationsmaybecomeappreciable。
Andwhetherornotthereensuedistinctdifferentiationsofotherindividuals
intomakersofparticulararticles，itisclearthattheoneoriginalcause
producesnotonlythefirstdualeffect，butanumberofsecondarydualeffects，
likeinkindbutminorindegree。Thisprocess，ofwhichtracesmaybeseen
amonggroupsofschoolboys，cannotwellproducealastingdistributionof
functionsinanunsettledtribe;butwheretheregrowsupafixedandmultiplying
community，itwillbecomepermanent，andincreasewitheachgeneration。An
additiontothenumberofcitizens，involvingagreaterdemandforevery
commodity，intensifiesthefunctionalactivityofeachspecializedperson
orclass;andthisrendersthespecializationmoredefinitewhereitexists，
andestablishesitwhereitisnascent。Byincreasingthepressureonthe
meansofsubsistence，alargerpopulationagainaugmentstheseresults;since
everyindividualisforcedmoreandmoretoconfinehimselftothatwhich
hecandobest，andbywhichhecangainmost。Andthisindustrialprogress
opensthewayforfurthergrowthofpopulation，whichreactsasbefore。Under
thesamestimulinewoccupationsarise。Amongcompetingworkers，somediscover
betterprocessesorbettermaterials。Thesubstitutionofbronzeforstone
entailsonhimwhofirstmakesitagreatincreaseofdemand——sogreat
anincreasethatpresentlyallhistimeisoccupiedinmakingthebronze
forthearticleshesells，andheisobligedtodeputethefashioningof
thesearticlestoothers;sothateventuallythemakingofbronze，thusdifferentiated
fromapre—existingoccupation，becomesanoccupationbyitself。Butnow
marktheramifiedchangeswhichfollowthischange。Bronzesoonreplaces
stonenotonlyinthearticlesitwasfirstusedfor，butinmanyothers;
andsoaffectsthemanufactureofthem。Further，itaffectstheprocesses
whichsuchimprovedutensilssubserve，andtheresultingproducts——modifies
buildings，carvings，dress，personaldecorations。Andallthesechangesreact
onthepeople—increasetheirmanipulativeskill，theirintelligence，theircomfort—refinetheirhabitsandtastes。Thisincreasingsocialheterogeneitythatresultsfromtheproduction
ofmanyeffectsbyonecause，cannotofCoursebefollowedout。Butleaving
theintermediatephasesofsocialdevelopment，letustakeanillustration
fromitspassingphase。Totracetheeffectsofsteampower，initsmanifold
applicationstomining，navigation，andmanufactures，wouldcarryusinto
unmanageabledetail。Letusconfineourselvestothelatestembodimentof
steam—power——thelocomotiveengine。This，astheproximatecauseofour
railway—system，haschangedthefaceofthecountry，thecourseoftrade，
andthehabitsofthepeople。Consider，first，thecomplicatedsetsofchanges
thatprecedethemakingofeveryrailway——theprovisionalarrangements，
themeetings，theregistration，thetrial—section，theparliamentarysurvey，
thelithographedplans，thebooksofreference，thelocaldepositsandnotices，
theapplicationtoParliament，thepassingStanding—OrdersCommittee，the
first，second，andthirdreadings:eachofwhichbriefheadsindicatesa
multiplicityoftransactions，andafurtherdevelopmentofsundryoccupations，
（asthoseofengineers，surveyors，lithographers，parliamentaryagents，share—brokers，）
andthecreationofsundryothers（asthoseoftraffic—takers，reference—makers）。
Consider，next，theyetmoremarkedchangesimpliedinrailwayconstruction
——thecuttings，embankings，tunnellings，diversionsofroads;thebuilding
ofbridges，viaducts，andstations;thelayingdownofballast，sleepers，
andrails;themakingofengines，tenders，carriages，andwagons:whichprocesses，
actinguponnumeroustrades，increasetheimportationoftimber，thequarrying
ofstone，themanufactureofiron，theminingofcoal，theburningofbricks;
instituteavarietyofspecialmanufacturesweeklyadvertisedintheRailway
Times;andcallintobeingsomenewclassesofworkers—drivers，stokers，
cleaners，plate—layers，signalmen。Thencomethechanges，morenumerousand
involvedstill，whichrailwaysinactionproduceonthecommunityatlarge。
