Itisnotsurprisingthatthedegreeofdifficultyinunitingtwospecies，andthedegreeofsterilityoftheirhybridoffspring，shouldgenerallycorrespond，thoughduetodistinctcauses；forbothdependontheamountofdifferenceofsomekindbetweenthespecieswhicharecrossed。Norisitsurprisingthatthefacilityofeffectingafirstcross，thefertilityofhybridsproducedfromit，andthecapacityofbeinggraftedtogether——thoughthislattercapacityevidentlydependsonwidelydifferentcircumstances——shouldallruntoacertainextentparallelwiththesystematicaffinityoftheformswhicharesubjectedtoexperiment；forsystematicaffinityattemptstoexpressallkindsofresemblancebetweenallspecies。
"Firstcrossesbetweenformsknowntobevarieties，orsufficientlyaliketobeconsideredasvarieties，andtheirmongreloffspring，areverygenerally，butnotquiteuniversally，fertile。Noristhisnearlygeneralandperfectfertilitysurprising，whenwerememberhowliablewearetoargueinacirclewithrespecttovarietiesinastateofNature；andwhenwerememberthatthegreaternumberofvarietieshavebeenproducedunderdomesticationbytheselectionofmereexternaldifferences，andnotofdifferencesinthereproductivesystem。Inallotherrespects，excludingfertility，thereisaclosegeneralresemblancebetweenhybridsandmongrels。"——Pp。276-8。
Wefullyagreewiththegeneraltenorofthisweightypassage；butforcibleasarethesearguments，andlittleasthevalueoffertilityorinfertilityasatestofspeciesmaybe，itmustnotbeforgottenthatthereallyimportantfact，sofarastheinquiryintotheoriginofspeciesgoes，is，thattherearesuchthingsinNatureasgroupsofanimalsandofplants，whosemembersareincapableoffertileunionwiththoseofothergroups；andthattherearesuchthingsashybrids，whichareabsolutelysterilewhencrossedwithotherhybrids。For，ifsuchphenomenaasthesewereexhibitedbyonlytwoofthoseassemblagesoflivingobjects，towhichthenameofspecies（whetheritbeusedinitsphysiologicalorinitsmorphologicalsense）isgiven，itwouldhavetobeaccountedforbyanytheoryoftheoriginofspecies，andeverytheorywhichcouldnotaccountforitwouldbe，sofar，imperfect。
Uptothispoint，wehavebeendealingwithmattersoffact，andthestatementswhichwehavelaidbeforethereaderwould，tothebestofourknowledge，beadmittedtocontainafairexpositionofwhatisatpresentknownrespectingtheessentialpropertiesofspecies，byallwhohavestudiedthequestion。Andwhatevermaybehistheoreticalviews，nonaturalistwillprobablybedisposedtodemurtothefollowingsummaryofthatexposition：——
Livingbeings，whetheranimalsorplants，aredivisibleintomultitudesofdistinctlydefinablekinds，whicharemorphologicalspecies。Theyarealsodivisibleintogroupsofindividuals，whichbreedfreelytogether，tendingtoreproducetheirlike，andarephysiologicalspecies。Normallyresemblingtheirparents，theoffspringofmembersofthesespeciesarestillliabletovary；andthevariationmaybeperpetuatedbyselection，asarace，whichrace，inmanycases，presentsallthecharacteristicsofamorphologicalspecies。Butitisnotasyetprovedthataraceeverexhibits，whencrossedwithanotherraceofthesamespecies，thosephenomenaofhybridizationwhichareexhibitedbymanyspecieswhencrossedwithotherspecies。Ontheotherhand，notonlyisitnotprovedthatallspeciesgiverisetohybridsinfertile’interse’，butthereismuchreasontobelievethat，incrossing，speciesexhibiteverygradationfromperfectsterilitytoperfectfertility。
Sucharethemostessentialcharacteristicsofspecies。Evenweremannotoneofthem——amemberofthesamesystemandsubjecttothesamelaws——thequestionoftheirorigin，theircausalconnexion，thatis，withtheotherphenomenaoftheuniverse，musthaveattractedhisattention，assoonashisintelligencehadraiseditselfabovethelevelofhisdailywants。
Indeedhistoryrelatesthatsuchwasthecase，andhasembalmedforusthespeculationsupontheoriginoflivingbeings，whichwereamongtheearliestproductsofthedawningintellectualactivityofman。Inthoseearlydayspositiveknowledgewasnottobehad，butthecravingafteritneeded，atallhazards，tobesatisfied，andaccordingtothecountry，ortheturnofthought，ofthespeculator，thesuggestionthatalllivingthingsarosefromthemudoftheNile，fromaprimevalegg，orfromsomemoreanthropomorphicagency，affordedasufficientresting-placeforhiscuriosity。ThemythsofPaganismareasdeadasOsirisorZeus，andthemanwhoshouldrevivethem，inoppositiontotheknowledgeofourtime，wouldbejustlylaughedtoscorn；butthecoevalimaginationscurrentamongtherudeinhabitantsofPalestine，recordedbywriterswhoseverynameandageareadmittedbyeveryscholartobeunknown，haveunfortunatelynotyetsharedtheirfate，but，evenatthisday，areregardedbynine-tenthsofthecivilizedworldastheauthoritativestandardoffactandthecriterionofthejusticeofscientificconclusions，inallthatrelatestotheoriginofthings，and，amongthem，ofspecies。Inthisnineteenthcentury，asatthedawnofmodernphysicalscience，thecosmogonyofthesemi-barbarousHebrewistheincubusofthephilosopherandtheopprobriumoftheorthodox。Whoshallnumberthepatientandearnestseekersaftertruth，fromthedaysofGalileountilnow，whoseliveshavebeenembitteredandtheirgoodnameblastedbythemistakenzealofBibliolaters？Whoshallcountthehostofweakermenwhosesenseoftruthhasbeendestroyedintheefforttoharmonizeimpossibilities——whoselifehasbeenwastedintheattempttoforcethegenerousnewwineofScienceintotheoldbottlesofJudaism，compelledbytheoutcryofthesamestrongparty？
Itistruethatifphilosophershavesuffered，theircausehasbeenamplyavenged。ExtinguishedtheologianslieaboutthecradleofeveryscienceasthestrangledsnakesbesidethatofHercules；andhistoryrecordsthatwheneverscienceandorthodoxyhavebeenfairlyopposed，thelatterhasbeenforcedtoretirefromthelists，bleedingandcrushedifnotannihilated；scotched，ifnotslain。ButorthodoxyistheBourbonoftheworldofthought。Itlearnsnot，neithercanitforget；andthough，atpresent，bewilderedandafraidtomove，itisaswillingasevertoinsistthatthefirstchapterofGenesiscontainsthebeginningandtheendofsoundscience；andtovisit，withsuchpettythunderboltsasitshalf-paralysedhandscanhurl，thosewhorefusetodegradeNaturetothelevelofprimitiveJudaism。
Philosophers，ontheotherhand，havenosuchaggressivetendencies。
Witheyesfixedonthenoblegoaltowhich"perasperaetardua"theytend，theymay，nowandthen，bestirredtomomentarywrathbytheunnecessaryobstacleswithwhichtheignorant，orthemalicious，encumber，iftheycannotbar，thedifficultpath；butwhyshouldtheirsoulsbedeeplyvexed？ThemajestyofFactisontheirside，andtheelementalforcesofNatureareworkingforthem。Notastarcomestothemeridianatitscalculatedtimebuttestifiestothejusticeoftheirmethods——theirbeliefsare"onewithfallingrainandwiththegrowingcorn。"Bydoubttheyareestablished，andopeninquiryistheirbosomfriend。Suchmenhavenofearoftraditionshowevervenerable，andnorespectforthemwhentheybecomemischievousandobstructive；buttheyhavebetterthanmereantiquarianbusinessinhand，andifdogmas，whichoughttobefossilbutarenot，arenotforcedupontheirnotice，theyaretoohappytotreatthemasnon-existent。
Thehypothesesrespectingtheoriginofspecieswhichprofesstostanduponascientificbasis，and，assuch，alonedemandseriousattention，areoftwokinds。Theone，the"specialcreation"hypothesis，presumeseveryspeciestohaveoriginatedfromoneormorestocks，thesenotbeingtheresultofthemodificationofanyotherformoflivingmatter——orarisingbynaturalagencies——butbeingproduced，assuch，byasupernaturalcreativeact。
Theother，theso-called"transmutation"hypothesis，considersthatallexistingspeciesaretheresultofthemodificationofpre-existingspecies，andthoseoftheirpredecessors，byagenciessimilartothosewhichatthepresentdayproducevarietiesandraces，andthereforeinanaltogethernaturalway；anditisaprobable，thoughnotanecessaryconsequenceofthishypothesis，thatalllivingbeingshavearisenfromasinglestock。Withrespecttotheoriginofthisprimitivestock，orstocks，thedoctrineoftheoriginofspeciesisobviouslynotnecessarilyconcerned。Thetransmutationhypothesis，forexample，isperfectlyconsistenteitherwiththeconceptionofaspecialcreationoftheprimitivegerm，orwiththesuppositionofitshavingarisen，asamodificationofinorganicmatter，bynaturalcauses。
ThedoctrineofspecialcreationowesitsexistenceverylargelytothesupposednecessityofmakingscienceaccordwiththeHebrewcosmogony；
butitiscurioustoobservethat，asthedoctrineisatpresentmaintainedbymenofscience，itisashopelesslyinconsistentwiththeHebrewviewasanyotherhypothesis。
Iftherebeanyresultwhichhascomemoreclearlyoutofgeologicalinvestigationthananother，itis，thatthevastseriesofextinctanimalsandplantsisnotdivisible，asitwasoncesupposedtobe，intodistinctgroups，separatedbysharply-markedboundaries。Therearenogreatgulfsbetweenepochsandformations——nosuccessiveperiodsmarkedbytheappearanceofplants，ofwateranimals，andoflandanimals，’enmasse’。Everyyearaddstothelistoflinksbetweenwhattheoldergeologistssupposedtobewidelyseparatedepochs：witnessthecragslinkingthedriftwitholdertertiaries；theMaestrichtbedslinkingthetertiarieswiththechalk；theSt。Cassianbedsexhibitinganabundantfaunaofmixedmesozoicandpalaeozoictypes，inrocksofanepochoncesupposedtobeeminentlypoorinlife；witness，lastly，theincessantdisputesastowhetheragivenstratumshallbereckoneddevonianorcarboniferous，silurianordevonian，cambrianorsilurian。
ThistruthisfurtherillustratedinamostinterestingmannerbytheimpartialandhighlycompetenttestimonyofM。Pictet，fromwhosecalculationsofwhatpercentageofthegeneraofanimals，existinginanyformation，livedduringtheprecedingformation，itresultsthatinnocaseistheproportionlessthan’one-third’，or33percent。Itisthetriassicformation，orthecommencementofthemesozoicepoch，whichhasreceivedthesmallestinheritancefromprecedingages。Theotherformationsnotuncommonlyexhibit60，80，oreven94percent。ofgeneraincommonwiththosewhoseremainsareimbeddedintheirpredecessor。Notonlyisthistrue，butthesubdivisionsofeachformationexhibitnewspeciescharacteristicof，andfoundonlyin，them；and，inmanycases，asintheliasforexample，theseparatebedsofthesesubdivisionsaredistinguishedbywell-markedandpeculiarformsoflife。Asection，ahundredfeetthick，willexhibit，atdifferentheights，adozenspeciesofammonite，noneofwhichpassesbeyonditsparticularzoneoflimestone，orclay，intothezonebelowitorintothataboveit；sothatthosewhoadoptthedoctrineofspecialcreationmustbepreparedtoadmit，thatatintervalsoftime，correspondingwiththethicknessofthesebeds，theCreatorthoughtfittointerferewiththenaturalcourseofeventsforthepurposeofmakinganewammonite。Itisnoteasytotransplantoneselfintotheframeofmindofthosewhocanacceptsuchaconclusionasthis，onanyevidenceshortofabsolutedemonstration；anditisdifficulttoseewhatistobegainedbysodoing，since，aswehavesaid，itisobviousthatsuchaviewoftheoriginoflivingbeingsisutterlyopposedtotheHebrewcosmogony。DeservingnoaidfromthepowerfularmofBibliolatry，then，doesthereceivedformofthehypothesisofspecialcreationderiveanysupportfromscienceorsoundlogic？Assuredlynotmuch。Theargumentsbroughtforwardinitsfavouralltakeoneform：
Ifspecieswerenotsupernaturallycreated，wecannotunderstandthefacts’x’or’y’，or’z’；wecannotunderstandthestructureofanimalsorplants，unlesswesupposetheywerecontrivedforspecialends；wecannotunderstandthestructureoftheeye，exceptbysupposingittohavebeenmadetoseewith；wecannotunderstandinstincts，unlesswesupposeanimalstohavebeenmiraculouslyendowedwiththem。
Asaquestionofdialectics，itmustbeadmittedthatthissortofreasoningisnotveryformidabletothosewhoarenottobefrightenedbyconsequences。Itisan’argumentumadignorantiam’——takethisexplanationorbeignorant。
ButsupposeweprefertoadmitourignoranceratherthanadoptahypothesisatvariancewithalltheteachingsofNature？Or，supposeforamomentweadmittheexplanation，andthenseriouslyaskourselveshowmuchthewiserarewe；whatdoestheexplanationexplain？Isitanymorethanagrandiloquentwayofannouncingthefact，thatwereallyknownothingaboutthematter？AphenomenonisexplainedwhenitisshowntobeacaseofsomegenerallawofNature；butthesupernaturalinterpositionoftheCreatorcan，bythenatureofthecase，exemplifynolaw，andifspecieshavereallyariseninthisway，itisabsurdtoattempttodiscusstheirorigin。
Or，lastly，letusaskourselveswhetheranyamountofevidencewhichthenatureofourfacultiespermitsustoattain，canjustifyusinassertingthatanyphenomenonisoutofthereachofnaturalcausation。Tothisenditisobviouslynecessarythatweshouldknowalltheconsequencestowhichallpossiblecombinations，continuedthroughunlimitedtime，cangiverise。Ifweknewthese，andfoundnonecompetenttooriginatespecies，weshouldhavegoodgroundfordenyingtheiroriginbynaturalcausation。Tillweknowthem，anyhypothesisisbetterthanonewhichinvolvesusinsuchmiserablepresumption。
Butthehypothesisofspecialcreationisnotonlyamerespeciousmaskforourignorance；itsexistenceinBiologymarkstheyouthandimperfectionofthescience。Forwhatisthehistoryofeverysciencebutthehistoryoftheeliminationofthenotionofcreative，orotherinterferences，withthenaturalorderofthephenomenawhicharethesubject-matterofthatscience？WhenAstronomywasyoung"themorningstarssangtogetherforjoy，"andtheplanetswereguidedintheircoursesbycelestialhands。Now，theharmonyofthestarshasresolveditselfintogravitationaccordingtotheinversesquaresofthedistances，andtheorbitsoftheplanetsarededuciblefromthelawsoftheforceswhichallowaschoolboy’sstonetobreakawindow。ThelightningwastheangeloftheLord；butithaspleasedProvidence，inthesemoderntimes，thatscienceshouldmakeitthehumblemessengerofman，andweknowthateveryflashthatshimmersaboutthehorizononasummer’seveningisdeterminedbyascertainableconditions，andthatitsdirectionandbrightnessmight，ifourknowledgeoftheseweregreatenough，havebeencalculated。
Thesolvencyofgreatmercantilecompaniesrestsonthevalidityofthelawswhichhavebeenascertainedtogoverntheseemingirregularityofthathumanlifewhichthemoralistbewailsasthemostuncertainofthings；plague，pestilence，andfamineareadmitted，byallbutfools，tobethenaturalresultofcausesforthemostpartfullywithinhumancontrol，andnottheunavoidabletorturesinflictedbywrathfulOmnipotenceuponHishelplesshandiwork。
Harmoniousordergoverningeternallycontinuousprogress——thewebandwoofofmatterandforceinterweavingbyslowdegrees，withoutabrokenthread，thatveilwhichliesbetweenusandtheInfinite——thatuniversewhichaloneweknoworcanknow；suchisthepicturewhichsciencedrawsoftheworld，andinproportionasanypartofthatpictureisinunisonwiththerest，somaywefeelsurethatitisrightlypainted。
ShallBiologyaloneremainoutofharmonywithhersistersciences？
Suchargumentsagainstthehypothesisofthedirectcreationofspeciesastheseareplainlyenoughdeduciblefromgeneralconsiderations；butthereare，inaddition，phenomenaexhibitedbyspeciesthemselves，andyetnotsomuchapartoftheirveryessenceastohaverequiredearliermention，whichareinthehighestdegreeperplexing，ifweadoptthepopularlyacceptedhypothesis。Sucharethefactsofdistributioninspaceandintime；thesingularphenomenabroughttolightbythestudyofdevelopment；thestructuralrelationsofspeciesuponwhichoursystemsofclassificationarefounded；thegreatdoctrinesofphilosophicalanatomy，suchasthatofhomology，orofthecommunityofstructuralplanexhibitedbylargegroupsofspeciesdifferingverywidelyintheirhabitsandfunctions。
ThespeciesofanimalswhichinhabittheseaonoppositesidesoftheisthmusofPanamaarewhollydistinct*theanimalsandplantswhichinhabitislandsarecommonlydistinctfromthoseoftheneighbouringmainlands，andyethaveasimilarityofaspect。
[footnote]*Recentinvestigationstendtoshowthatthisstatementisnotstrictlyaccurate。——1870。
ThemammalsofthelatesttertiaryepochintheOldandNewWorldsbelongtothesamegenera，orfamilygroups，asthosewhichnowinhabitthesamegreatgeographicalarea。Thecrocodilianreptileswhichexistedintheearliestsecondaryepochweresimilaringeneralstructuretothosenowliving，butexhibitslightdifferencesintheirvertebrae，nasalpassages，andoneortwootherpoints。Theguinea-pighasteethwhichareshedbeforeitisborn，andhencecanneversubservethemasticatorypurposeforwhichtheyseemcontrived，and，inlikemanner，thefemaledugonghastuskswhichnevercutthegum。Allthemembersofthesamegreatgrouprunthroughsimilarconditionsintheirdevelopment，andalltheirparts，intheadultstate，arearrangedaccordingtothesameplan。Manismorelikeagorillathanagorillaislikealemur。Suchareafew，takenatrandom，amongthemultitudesofsimilarfactswhichmodernresearchhasestablished；butwhenthestudentseeksforanexplanationofthemfromthesupportersofthereceivedhypothesisoftheoriginofspecies，thereplyhereceivesis，insubstance，ofOrientalsimplicityandbrevity——"Mashallah！itsopleasesGod！"TherearedifferentspeciesonoppositesidesoftheisthmusofPanama，becausetheywerecreateddifferentonthetwosides。Thepliocenemammalsareliketheexistingones，becausesuchwastheplanofcreation；andwefindrudimentalorgansandsimilarityofplan，becauseithaspleasedtheCreatortosetbeforeHimselfa"divineexemplarorarchetype，"andtocopyitinHisworks；andsomewhatill，thosewhoholdthisviewimply，insomeofthem。Thatsuchverbalhocus-pocusshouldbereceivedassciencewillonedayberegardedasevidenceofthelowstateofintelligenceinthenineteenthcentury，justasweamuseourselveswiththephraseologyaboutNature’sabhorrenceofavacuum，wherewithTorricelli’scompatriotsweresatisfiedtoexplaintheriseofwaterinapump。Andbeitrecollectedthatthissortofsatisfactionworksnotonlynegativebutpositiveill，bydiscouraginginquiry，andsodeprivingmanoftheusufructofoneofthemostfertilefieldsofhisgreatpatrimony，Nature。
Theobjectionstothedoctrineoftheoriginofspeciesbyspecialcreationwhichhavebeendetailed，musthaveoccurred，withmoreorlessforce，tothemindofeveryonewhohasseriouslyandindependentlyconsideredthesubject。Itisthereforenowonderthat，fromtimetotime，thishypothesisshouldhavebeenmetbycounterhypotheses，allaswell，andsomebetterfoundedthanitself；anditiscurioustoremarkthattheinventorsoftheopposingviewsseemtohavebeenledintothemasmuchbytheirknowledgeofgeology，asbytheiracquaintancewithbiology。Infact，whenthemindhasonceadmittedtheconceptionofthegradualproductionofthepresentphysicalstateofourglobe，bynaturalcausesoperatingthroughlongagesoftime，itwillbelittledisposedtoallowthatlivingbeingshavemadetheirappearanceinanotherway，andthespeculationsofDeMailletandhissuccessorsarethenaturalcomplementofScilla’sdemonstrationofthetruenatureoffossils。
AcontemporaryofNewtonandofLeibnitz，sharingthereforeintheintellectualactivityoftheremarkableagewhichwitnessedthebirthofmodernphysicalscience，BenoitdeMailletspentalonglifeasaconsularagentoftheFrenchGovernmentinvariousMediterraneanports。
Forsixteenyears，infact，heheldtheofficeofConsul-GeneralinEgypt，andthewonderfulphenomenaofferedbythevalleyoftheNileappeartohavestronglyimpressedhismind，tohavedirectedhisattentiontoallfactsofasimilarorderwhichcamewithinhisobservation，andtohaveledhimtospeculateontheoriginofthepresentconditionofourglobeandofitsinhabitants。But，withallhisardourforscience，DeMailletseemstohavehesitatedtopublishviewswhich，notwithstandingtheingeniousattemptstoreconcilethemwiththeHebrewhypothesiscontainedintheprefaceto"Telliamed，"
werehardlylikelytobereceivedwithfavourbyhiscontemporaries。
ButashorttimehadelapsedsincemorethanoneofthegreatanatomistsandphysicistsoftheItalianschoolhadpaiddearlyfortheirendeavourstodissipatesomeoftheprevalenterrors；andtheirillustriouspupil，Harvey，thefounderofmodernphysiology，hadnotfaredsowell，inacountrylessoppressedbythebenumbinginfluencesoftheology，astotemptanymantofollowhisexample。Probablynotuninfluencedbytheseconsiderations，hisCatholicmajesty’sConsul-GeneralforEgyptkepthistheoriestohimselfthroughoutalonglife，for’Telliamed，’theonlyscientificworkwhichisknowntohaveproceededfromhispen，wasnotprintedtill1735，whenitsauthorhadreachedtheripeageofseventy-nine；andthoughDeMailletlivedthreeyearslonger，hisbookwasnotgiventotheworldbefore1748。Eventhenitwasanonymoustothosewhowerenotinthesecretoftheanagrammaticcharacterofitstitle；andtheprefaceanddedicationaresowordedas，incaseofnecessity，togivetheprinterafairchanceoffallingbackontheexcusethattheworkwasintendedforamere’jeud’esprit’。
ThespeculationsofthesuppositiousIndiansage，thoughquiteassoundasthoseofmanya"MosaicGeology，"whichsellsexceedinglywell，havenogreatvalueifweconsiderthembythelightofmodernscience。Thewatersaresupposedtohaveoriginallycoveredthewholeglobe；tohavedepositedtherockymasseswhichcomposeitsmountainsbyprocessescomparabletothosewhicharenowformingmud，sand，andshingle；andthentohavegraduallyloweredtheirlevel，leavingthespoilsoftheiranimalandvegetableinhabitantsembeddedinthestrata。Asthedrylandappeared，certainoftheaquaticanimalsaresupposedtohavetakentoit，andtohavebecomegraduallyadaptedtoterrestrialandaerialmodesofexistence。Butifweregardthegeneraltenorandstyleofthereasoninginrelationtothestateofknowledgeoftheday，twocircumstancesappearverywellworthyofremark。Thefirst，thatDeMaillethadanotionofthemodifiabilityoflivingforms（thoughwithoutanypreciseinformationonthesubject），andhowsuchmodifiabilitymightaccountfortheoriginofspecies；thesecond，thatheveryclearlyapprehendedthegreatmoderngeologicaldoctrine，sostronglyinsisteduponbyHutton，andsoablyandcomprehensivelyexpoundedbyLyell，thatwemustlooktoexistingcausesfortheexplanationofpastgeologicalevents。Indeed，thefollowingpassageofthepreface，inwhichDeMailletissupposedtospeakoftheIndianphilosopherTelliamed，his’alterego’，mighthavebeenwrittenbythemostphilosophicaluniformitarianofthepresentday：——
"Cequ’ilyad’etonnant，estquepourarriveracesconnoissancesilsembleavoirpervertil’ordrenaturel，puisqu’aulieudes’attacherd’abordarechercherl’originedenotreglobeilacommencepartravailleras’instruiredelanature。Maisal’entendre，cerenversementdel’ordreaetepourluil’effetd’ungeniefavorablequil’aconduitpasapasetcommeparlamainauxdecouverteslesplussublimes。C’estendecomposantlasubstancedeceglobeparuneanatomieexactedetoutessespartiesqu’ilapremierementapprisdequellesmatieresiletaitcomposeetquelsarrangemenscesmemesmatieresobservaiententreelles。Ceslumieresjointesal’espritdecomparaisontoujoursnecessaireaquiconqueentreprenddepercerlesvoilesdontlanatureaimeasecacher，ontservideguideanotrephilosophepourparveniradesconnoissancesplusinteressantes。Parlamatiereetl’arrangementdecescompositionsilpretendavoirreconnuquelleestlaveritableoriginedeceglobequenoushabitons，commentetparquiilaeteforme。"——Pp。xix。xx。
ButDeMailletwasbeforehisage，andascouldhardlyfailtohappentoonewhospeculatedonazoologicalandbotanicalquestionbeforeLinnaeus，andonaphysiologicalproblembeforeHaller，hefellintogreaterrorshereandthere；andhence，perhaps，thegeneralneglectofhiswork。Robinet’sspeculationsareratherbehind，thaninadvanceof，thoseofDeMaillet；andthoughLinnaeusmayhaveplayedwiththehypothesisoftransmutation，itobtainednoserioussupportuntilLamarckadoptedit，andadvocateditwithgreatabilityinhis’PhilosophieZoologique。’
Impelledtowardsthehypothesisofthetransmutationofspecies，partlybyhisgeneralcosmologicalandgeologicalviews；partlybytheconceptionofagraduated，thoughirregularlybranching，scaleofbeing，whichhadarisenoutofhisprofoundstudyofplantsandofthelowerformsofanimallife，Lamarck，whosegenerallineofthoughtoftencloselyresemblesthatofDeMaillet，madeagreatadvanceuponthecrudeandmerelyspeculativemannerinwhichthatwriterdealswiththequestionoftheoriginoflivingbeings，byendeavouringtofindphysicalcausescompetenttoeffectthatchangeofonespeciesintoanother，whichDeMaillethadonlysupposedtooccur。AndLamarckconceivedthathehadfoundinNaturesuchcauses，amplysufficientforthepurposeinview。Itisaphysiologicalfact，hesays，thatorgansareincreasedinsizebyaction，atrophiedbyinaction；itisanotherphysiologicalfactthatmodificationsproducedaretransmissibletooffspring。Changetheactionsofananimal，therefore，andyouwillchangeitsstructure，byincreasingthedevelopmentofthepartsnewlybroughtintouseandbythediminutionofthoselessused；butbyalteringthecircumstanceswhichsurroundityouwillalteritsactions，andhence，inthelongrun，changeofcircumstancemustproducechangeoforganization。Allthespeciesofanimals，therefore，are，inLamarck’sview，theresultoftheindirectactionofchangesofcircumstance，uponthoseprimitivegermswhichheconsideredtohaveoriginallyarisen，byspontaneousgeneration，withinthewatersoftheglobe。Itiscurious，however，thatLamarckshouldinsistsostrongly*
ashehasdone，thatcircumstancesneverinanydegreedirectlymodifytheformortheorganizationofanimals，butonlyoperatebychangingtheirwantsandconsequentlytheiractions；forhetherebybringsuponhimselftheobviousquestion，how，then，doplants，whichcannotbesaidtohavewantsoractions，becomemodified？Tothishereplies，thattheyaremodifiedbythechangesintheirnutritiveprocesses，whichareeffectedbychangingcircumstances；anditdoesnotseemtohaveoccurredtohimthatsuchchangesmightbeaswellsupposedtotakeplaceamonganimals。
[footnote]*See’Phil。Zoologique，’vol。i。p。222，’etseq。’
WhenwehavesaidthatLamarckfeltthatmerespeculationwasnotthewaytoarriveattheoriginofspecies，butthatitwasnecessary，inordertotheestablishmentofanysoundtheoryonthesubject，todiscoverbyobservationorotherwise，some’veracausa’，competenttogiverisetothem；thatheaffirmedthetrueorderofclassificationtocoincidewiththeorderoftheirdevelopmentonefromanother；thatheinsistedonthenecessityofallowingsufficienttime，verystrongly；
andthatallthevarietiesofinstinctandreasonweretracedbackbyhimtothesamecauseasthatwhichhasgivenrisetospecies，wehaveenumeratedhischiefcontributionstotheadvanceofthequestion。Ontheotherhand，fromhisignoranceofanypowerinNaturecompetenttomodifythestructureofanimals，exceptthedevelopmentofparts，oratrophyofthem，inconsequenceofachangeofneeds，Lamarckwasledtoattachinfinitelygreaterweightthanitdeservestothisagency，andtheabsurditiesintowhichhewasledhavemetwithdeservedcondemnation。Ofthestruggleforexistence，onwhich，asweshallsee，Mr。Darwinlayssuchgreatstress，hehadnoconception；indeed，hedoubtswhethertherereallyaresuchthingsasextinctspecies，unlesstheybesuchlargeanimalsasmayhavemettheirdeathatthehandsofman；andsolittledoeshedreamoftherebeinganyotherdestructivecausesatwork，that，indiscussingthepossibleexistenceoffossilshells，heasks，"Pourquoid’ailleursseroient-ilsperduesdesquel’hommen’apuopererleurdestruction？"（’Phil。Zool。，’vol。i。p。
77。）OftheinfluenceofselectionLamarckhasaslittlenotion，andhemakesnouseofthewonderfulphenomenawhichareexhibitedbydomesticatedanimals，andillustrateitspowers。ThevastinfluenceofCuvierwasemployedagainsttheLamarckianviews，and，astheuntenabilityofsomeofhisconclusionswaseasilyshown，hisdoctrinessankundertheopprobriumofscientific，aswellasoftheological，heterodoxy。Norhavetheeffortsmadeoflateyearstorevivethemtendedtore-establishtheircreditinthemindsofsoundthinkersacquaintedwiththefactsofthecase；indeeditmaybedoubtedwhetherLamarckhasnotsufferedmorefromhisfriendsthanfromhisfoes。
Twoyearsago，infact，thoughweventuretoquestionifeventhestrongestsupportersofthespecialcreationhypothesishadnot，nowandthen，anuneasyconsciousnessthatallwasnotright，theirpositionseemedmoreimpregnablethanever，ifnotbyitsowninherentstrength，atanyratebytheobviousfailureofalltheattemptswhichhadbeenmadetocarryit。Ontheotherhand，howevermuchthefew，whothoughtdeeplyonthequestionofspecies，mightberepelledbythegenerallyreceiveddogmas，theysawnowayofescapingfromthemsavebytheadoptionofsuppositionssolittlejustifiedbyexperimentorbyobservationastobeatleastequallydistasteful。
Thechoicelaybetweentwoabsurditiesandamiddleconditionofuneasyscepticism；whichlast，howeverunpleasantandunsatisfactory，wasobviouslytheonlyjustifiablestateofmindunderthecircumstances。
Suchbeingthegeneralfermentinthemindsofnaturalists，itisnowonderthattheymusteredstrongintheroomsoftheLinnaeanSociety，onthe1stofJulyoftheyear1858，toheartwopapersbyauthorslivingonoppositesidesoftheglobe，workingouttheirresultsindependently，andyetprofessingtohavediscoveredoneandthesamesolutionofalltheproblemsconnectedwithspecies。Theoneoftheseauthorswasanablenaturalist，Mr。Wallace，whohadbeenemployedforsomeyearsinstudyingtheproductionsoftheislandsoftheIndianArchipelago，andwhohadforwardedamemoirembodyinghisviewstoMr。
Darwin，forcommunicationtotheLinnaeanSociety。Onperusingtheessay，Mr。Darwinwasnotalittlesurprisedtofindthatitembodiedsomeoftheleadingideasofagreatworkwhichhehadbeenpreparingfortwentyyears，andpartsofwhich，containingadevelopmentoftheverysameviews，hadbeenperusedbyhisprivatefriendsfifteenorsixteenyearsbefore。Perplexedinwhatmannertodofulljusticebothtohisfriendandtohimself，Mr。DarwinplacedthematterinthehandsofDr。HookerandSirCharlesLyell，bywhoseadvicehecommunicatedabriefabstractofhisownviewstotheLinnaeanSociety，atthesametimethatMr。Wallace’spaperwasread。Ofthatabstract，theworkonthe’OriginofSpecies’isanenlargement；butacompletestatementofMr。Darwin’sdoctrineislookedforinthelargeandwell-illustratedworkwhichheissaidtobepreparingforpublication。
TheDarwinianhypothesishasthemeritofbeingeminentlysimpleandcomprehensibleinprinciple，anditsessentialpositionsmaybestatedinaveryfewwords：allspecieshavebeenproducedbythedevelopmentofvarietiesfromcommonstocks；bytheconversionofthese，firstintopermanentracesandthenintonewspecies，bytheprocessof’naturalselection’，whichprocessisessentiallyidenticalwiththatartificialselectionbywhichmanhasoriginatedtheracesofdomesticanimals——the’struggleforexistence’takingtheplaceofman，andexerting，inthecaseofnaturalselection，thatselectiveactionwhichheperformsinartificialselection。
TheevidencebroughtforwardbyMr。Darwininsupportofhishypothesisisofthreekinds。First，heendeavourstoprovethatspeciesmaybeoriginatedbyselection；secondly，heattemptstoshowthatnaturalcausesarecompetenttoexertselection；andthirdly，hetriestoprovethatthemostremarkableandapparentlyanomalousphenomenaexhibitedbythedistribution，development，andmutualrelationsofspecies，canbeshowntobededuciblefromthegeneraldoctrineoftheirorigin，whichhepropounds，combinedwiththeknownfactsofgeologicalchange；andthat，evenifallthesephenomenaarenotatpresentexplicablebyit，nonearenecessarilyinconsistentwithit。
TherecannotbeadoubtthatthemethodofinquirywhichMr。Darwinhasadoptedisnotonlyrigorouslyinaccordancewiththecanonsofscientificlogic，butthatitistheonlyadequatemethod。Criticsexclusivelytrainedinclassicsorinmathematics，whohaveneverdeterminedascientificfactintheirlivesbyinductionfromexperimentorobservation，pratelearnedlyaboutMr。Darwin’smethod，whichisnotinductiveenough，notBaconianenough，forsooth，forthem。Butevenifpracticalacquaintancewiththeprocessofscientificinvestigationisdeniedthem，theymaylearn，bytheperusalofMr。
Mill’sadmirablechapter"OntheDeductiveMethod，"thattherearemultitudesofscientificinquiriesinwhichthemethodofpureinductionhelpstheinvestigatorbutaverylittleway。
"Themodeofinvestigation，"saysMr。Mill，"which，fromtheprovedinapplicabilityofdirectmethodsofobservationandexperiment，remainstousasthemainsourceoftheknowledgewepossess，orcanacquire，respectingtheconditionsandlawsofrecurrenceofthemorecomplexphenomena，iscalled，initsmostgeneralexpression，thedeductivemethod，andconsistsofthreeoperations：thefirst，oneofdirectinduction；thesecond，ofratiocination；andthethird，ofverification。"
Now，theconditionswhichhavedeterminedtheexistenceofspeciesarenotonlyexceedinglycomplex，but，sofarasthegreatmajorityofthemareconcerned，arenecessarilybeyondourcognizance。ButwhatMr。
DarwinhasattemptedtodoisinexactaccordancewiththerulelaiddownbyMr。Mill；hehasendeavouredtodeterminecertaingreatfactsinductively，byobservationandexperiment；hehasthenreasonedfromthedatathusfurnished；andlastly，hehastestedthevalidityofhisratiocinationbycomparinghisdeductionswiththeobservedfactsofNature。Inductively，Mr。Darwinendeavourstoprovethatspeciesariseinagivenway。Deductively，hedesirestoshowthat，iftheyariseinthatway，thefactsofdistribution，development，classification，etc。，maybeaccountedfor，’i。e。’maybededucedfromtheirmodeoforigin，combinedwithadmittedchangesinphysicalgeographyandclimate，duringanindefiniteperiod。Andthisexplanation，orcoincidenceofobservedwithdeducedfacts，is，sofarasitextends，averificationoftheDarwinianview。
ThereisnofaulttobefoundwithMr。Darwin’smethod，then；butitisanotherquestionwhetherhehasfulfilledalltheconditionsimposedbythatmethod。Isitsatisfactorilyproved，infact，thatspeciesmaybeoriginatedbyselection？thatthereissuchathingasnaturalselection？thatnoneofthephenomenaexhibitedbyspeciesareinconsistentwiththeoriginofspeciesinthisway？Ifthesequestionscanbeansweredintheaffirmative，Mr。Darwin’sviewstepsoutoftherankofhypothesesintothoseofprovedtheories；but，solongastheevidenceatpresentadducedfallsshortofenforcingthataffirmation，solong，toourminds，mustthenewdoctrinebecontenttoremainamongtheformer——anextremelyvaluable，andinthehighestdegreeprobable，doctrine，indeedtheonlyextanthypothesiswhichisworthanythinginascientificpointofview；butstillahypothesis，andnotyetthetheoryofspecies。
Aftermuchconsideration，andwithassuredlynobiasagainstMr。
Darwin’sviews，itisourclearconvictionthat，astheevidencestands，itisnotabsolutelyproventhatagroupofanimals，havingallthecharactersexhibitedbyspeciesinNature，haseverbeenoriginatebyselection，whetherartificialornatural。Groupshavingthemorphologicalcharacterofspecies，distinctandpermanentracesinfact，havebeensoproducedoverandoveragain；butthereisnopositiveevidence，atpresent，thatanygroupofanimalshas，byvariationandselectivebreeding，givenrisetoanothergroupwhichwas，evenintheleastdegree，infertilewiththefirst。Mr。Darwinisperfectlyawareofthisweakpoint，andbringsforwardamultitudeofingeniousandimportantargumentstodiminishtheforceoftheobjection。Weadmitthevalueoftheseargumentstotheirfullestextent；nay，wewillgosofarastoexpressourbeliefthatexperiments，conductedbyaskilfulphysiologist，wouldveryprobablyobtainthedesiredproductionofmutuallymoreorlessinfertilebreedsfromacommonstock，inacomparativelyfewyears；butstill，asthecasestandsatpresent，this"littleriftwithinthelute"isnottobedisguisednoroverlooked。
IntheremainderofMr。Darwin’sargumentourownprivateingenuityhasnothithertoenabledustopickholesofanygreatimportance；andjudgingbywhatwehearandread，otheradventurersinthesamefielddonotseemtohavebeenmuchmorefortunate。Ithasbeenurged，forinstance，thatinhischaptersonthestruggleforexistenceandonnaturalselection，Mr。Darwindoesnotsomuchprovethatnaturalselectiondoesoccur，asthatitmustoccur；but，infact，noothersortofdemonstrationisattainable。AracedoesnotattractourattentioninNatureuntilithas，inallprobability，existedforaconsiderabletime，andthenitistoolatetoinquireintotheconditionsofitsorigin。Again，itissaidthatthereisnorealanalogybetweentheselectionwhichtakesplaceunderdomestication，byhumaninfluence，andanyoperationwhichcanbeeffectedbyNature，formaninterferesintelligently。Reducedtoitselements，thisargumentimpliesthataneffectproducedwithtroublebyanintelligentagentmust，’afortiori’，bemoretroublesome，ifnotimpossible，toanunintelligentagent。EvenputtingasidethequestionwhetherNature，actingasshedoesaccordingtodefiniteandinvariablelaws，canberightlycalledanunintelligentagent，suchapositionasthisiswhollyuntenable。Mixsaltandsand，anditshallpuzzlethewisestofmen，withhismerenaturalappliances，toseparateallthegrainsofsandfromallthegrainsofsalt；butashowerofrainwilleffectthesameobjectintenminutes。Andso，whilemanmayfindittaxallhisintelligencetoseparateanyvarietywhicharises，andtobreedselectivelyfromit，thedestructiveagenciesincessantlyatworkinNature，iftheyfindonevarietytobemoresolubleincircumstancesthantheother，willinevitably，inthelongrun，eliminateit。
AfrequentandajustobjectiontotheLamarckianhypothesisofthetransmutationofspeciesisbasedupontheabsenceoftransitionalformsbetweenmanyspecies。ButagainsttheDarwinianhypothesisthisargumenthasnoforce。Indeed，oneofthemostvaluableandsuggestivepartsofMr。Darwin’sworkisthatinwhichheproves，thatthefrequentabsenceoftransitionsisanecessaryconsequenceofhisdoctrine，andthatthestockwhencetwoormorespecieshavesprung，needinnorespectbeintermediatebetweenthesespecies。Ifanytwospecieshavearisenfromacommonstockinthesamewayasthecarrierandthepouter，say，havearisenfromtherock-pigeon，thenthecommonstockofthesetwospeciesneedbenomoreintermediatebetweenthetwothantherock-pigeonisbetweenthecarrierandpouter。Clearlyappreciatetheforceofthisanalogy，andalltheargumentsagainsttheoriginofspeciesbyselection，basedontheabsenceoftransitionalforms，falltotheground。AndMr。Darwin’spositionmight，wethink，havebeenevenstrongerthanitisifhehadnotembarrassedhimselfwiththeaphorism，"Naturanonfacitsaltum，"whichturnsupsoofteninhispages。Webelieve，aswehavesaidabove，thatNaturedoesmakejumpsnowandthen，andarecognitionofthefactisofnosmallimportanceindisposingofmanyminorobjectionstothedoctrineoftransmutation。
Butwemustpause。ThediscussionofMr。Darwin’sargumentsindetailwouldleadusfarbeyondthelimitswithinwhichweproposed，atstarting，toconfinethisarticle。Ourobjecthasbeenattainedifwehavegivenanintelligible，howeverbrief，accountoftheestablishedfactsconnectedwithspecies，andoftherelationoftheexplanationofthosefactsofferedbyMr。Darwintothetheoreticalviewsheldbyhispredecessorsandhiscontemporaries，and，aboveall，totherequirementsofscientificlogic。Wehaveventuredtopointoutthatitdoesnot，asyet，satisfyallthoserequirements；butwedonothesitatetoassertthatitisassuperiortoanyprecedingorcontemporaryhypothesis，intheextentofobservationalandexperimentalbasisonwhichitrests，initsrigorouslyscientificmethod，andinitspowerofexplainingbiologicalphenomena，aswasthehypothesisofCopernicustothespeculationsofPtolemy。Buttheplanetaryorbitsturnedouttobenotquitecircularafterall，and，grandaswastheserviceCopernicusrenderedtoscience，KeplerandNewtonhadtocomeafterhim。WhatiftheorbitofDarwinismshouldbealittletoocircular？Whatifspeciesshouldofferresidualphenomena，hereandthere，notexplicablebynaturalselection？Twentyyearshencenaturalistsmaybeinapositiontosaywhetherthisis，orisnot，thecase；butineithereventtheywillowetheauthorof’TheOriginofSpecies’animmensedebtofgratitude。Weshouldleaveaverywrongimpressiononthereader’smindifwepermittedhimtosupposethatthevalueofthatworkdependswhollyontheultimatejustificationofthetheoreticalviewswhichitcontains。Onthecontrary，iftheyweredisprovedto-morrow，thebookwouldstillbethebestofitskind——themostcompendiousstatementofwell-siftedfactsbearingonthedoctrineofspeciesthathaseverappeared。ThechaptersonVariation，ontheStruggleforExistence，onInstinct，onHybridism，ontheImperfectionoftheGeologicalRecord，onGeographicalDistribution，havenotonlynoequals，but，sofarasourknowledgegoes，nocompetitors，withintherangeofbiologicalliterature。Andviewedasawhole，wedonotbelievethat，sincethepublicationofVonBaer’sResearchesonDevelopment，thirtyyearsago，anyworkhasappearedcalculatedtoexertsolargeaninfluence，notonlyonthefutureofBiology，butinextendingthedominationofScienceoverregionsofthoughtintowhichshehas，asyet，hardlypenetrated。