PleasereturnLyell’sletters。
　　WhatacapitalletterofLyell’sthattoyouis，andwhatawonderfulmanheis。IdifferfromhimgreatlyinthinkingthatthosewhobelievethatspeciesareNOTfixedwillmultiplyspecificnames:IknowinmyowncasemymostfrequentsourceofdoubtwaswhetherotherswouldnotthinkthisorthatwasaGod—createdBarnacle，andsurelydeservedaname。OtherwiseI
　　shouldonlyhavethoughtwhethertheamountofdifferenceandpermanencewassufficienttojustifyaname:Iam，also，surprisedathisthinkingitimmaterialwhetherspeciesareabsoluteornot:wheneveritisprovedthatallspeciesareproducedbygeneration，bylawsofchange，whatgoodevidenceweshallhaveofthegapsinformations。AndwhatascienceNaturalHistorywillbe，whenweareinourgraves，whenallthelawsofchangearethoughtoneofthemostimportantpartsofNaturalHistory。
　　IcannotconceivewhyLyellthinkssuchnotionsasmineorof’Vestiges，’
　　willinvalidatespecificcentres。ButImustnotrunonandtakeupyourtime。MyMS。willnot，Ifear，becopiedbeforeyougoabroad。Withheartythanks。
　　Everyours，C。DARWIN。
　　P。S。——Aftergivingmuchcondensed，myargumentversuscontinentalextensions，Ishallappendsomesuchsentence，asthattwobetterjudgesthanmyselfhaveconsideredthesearguments，andattachnoweighttothem。
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，August5th[1856]……IquiteagreeaboutLyell’sletterstome，which，thoughtomeinteresting，haveaffordedmenonewlight。Yourletters，undertheGEOLOGICALpointofview，havebeenmorevaluabletome。YoucannotimaginehowearnestlyIwishIcouldswallowcontinentalextension，butI
　　cannot;themoreIthink（andIcannotgetthesubjectoutofmyhead），themoredifficultIfindit。Iftherewereonlysomehalf—dozencases，I
　　shouldnotfeeltheleastdifficulty;butthegeneralityofthefactsofallislands（exceptoneortwo）havingaconsiderablepartoftheirproductionsincommonwithoneormoremainlandsutterlystaggersme。WhatawonderfulcaseoftheEpacridae！Itismostvexatious，alsohumiliating，tomethatIcannotfollowandsubscribetothewayinwhichyoustrikinglyputyourviewofthecase。Ilookatyourfacts（aboutEucalyptus，etc。）
　　asDAMNINGagainstcontinentalextension，andifyoulikealsodamningagainstmigration，oratleastofENORMOUSdifficulty。Iseethegroundofourdifference（inaletterImustputmyselfonanequalityinarguing）
　　lies，inmyopinion，thatscarcelyanythingisknownofmeansofdistribution。IquiteagreewithA。DeCandolle’s（andIdaresayyour）
　　opinionthatitispoorworkputtingtogetherthemerelyPOSSIBLEmeansofdistribution;butIseenootherwayinwhichthesubjectcanbeattacked，forIthinkthatA。DeCandolle’sargument，thatnoplantshavebeenintroducedintoEnglandexceptbyman’sagency，[is]ofnoweight。I
　　cannotbutthinkthatthetheoryofcontinentalextensiondoesdosomelittleharmasstoppinginvestigationofthemeansofdispersal，which，whetherNEGATIVEorpositive，seemstomeofvalue;whennegatived，theneveryonewhobelievesinsinglecentreswillhavetoadmitcontinentalextensions……Iseefromyourremarksthatyoudonotunderstandmynotions（whetherornoworthanything）aboutmodification;Iattributeverylittletothedirectactionofclimate，etc。Isuppose，inregardtospecificcentres，weareatcrosspurposes;Ishouldcallthekitchengardeninwhichtheredcabbagewasproduced，orthefarminwhichBakewellmadetheShorthorncattle，thespecificcentreoftheseSPECIES！Andsurelythisiscentralisationenough！
　　Ithankyoumostsincerelyforallyourassistance;andwhetherornomybookmaybewretched，youhavedoneyourbesttomakeitlesswretched。
　　SometimesIaminverygoodspiritsandsometimesverylowaboutit。Myownmindisdecidedonthequestionoftheoriginofspecies;but，goodheavens，howlittlethatisworth！……
　　[Withregardto"specificcentres，"apassagefromaletterdatedJuly25，1856，bySirCharlesLyelltoSirJ。D。Hooker（’Life’ii。page216）isofinterest:
　　"IfearmuchthatifDarwinarguesthatspeciesarephantoms，hewillalsohavetoadmitthatsinglecentresofdispersionarephantomsalso，andthatwoulddeprivemeofmuchofthevaluewhichIascribetothepresentprovincesofanimalsandplants，asillustratingmodernandtertiarychangesinphysicalgeography。"
　　Heseemstohaverecognised，however，thatthephantomdoctrinewouldsoonhavetobefaced，forhewroteinthesameletter:"WhetherDarwinpersuadesyouandmetorenounceourfaithinspecies（whengeologicalepochsareconsidered）ornot，Iforeseethatmanywillgoovertotheindefinitemodifiabilitydoctrine。"
　　Intheautumnmyfatherwasstillworkingatgeographicaldistribution，andagainsoughttheaidofSirJ。D。Hooker。
　　ALETTERTOSIRJ。D。HOOKER
　　[September，1856]。
　　"Inthecourseofsomeweeks，youunfortunatewretch，youwillhavemyMS。
　　ononepointofGeographicalDistribution。Iwillhowever，neverasksuchafavouragain;butinregardtothisonepieceofMS。，itisofinfiniteimportancetomeforyoutoseeit;forneverinmylifehaveIfeltsuchdifficultywhattodo，andIheartilywishIcouldslurthewholesubjectover。"
　　InalettertoSirJ。D。Hooker（June，1856），thefollowingcharacteristicpassageoccurs，suggested，nodoubt，bythekindofworkwhichhischapteronGeographicalDistributionentailed:
　　"Thereiswonderfulilllogicinhis[E。Forbes’]famousandadmirablememoirondistribution，asitappearstome，nowthatIhavegotitupsoastogivetheheadsinapage。Dependonit，mysayingisatrueone，viz。，thatacompilerisaGREATman，andanoriginalmanacommonplaceman。Anyfoolcangeneraliseandspeculate;but，oh，myheavens！TogetupATSECONDHANDaNewZealandFlora，thatiswork。"
　　CHARLESDARWINTOW。D。FOX。
　　October3[1856]……IrememberyouprotestedagainstLyell’sadviceofwritingaSKETCHofmyspeciesdoctrines。Well，whenIbeganIfounditsuchunsatisfactoryworkthatIhavedesisted，andamnowdrawingupmyworkasperfectasmymaterialsofnineteenyears’collectingsuffice，butdonotintendtostoptoperfectanylineofinvestigationbeyondcurrentwork。ThusfarandnofartherIshallfollowLyell’surgentadvice。Yourremarksweighedwithmeconsiderably。Ifindtomysorrowitwillruntoquiteabigbook。Ihavefoundmycarefulworkatpigeonsreallyinvaluable，asenlighteningmeonmanypointsonvariationunderdomestication。Thecopiousoldliterature，bywhichIcantracethegradualchangesinthebreedsofpigeonshasbeenextraordinarilyusefultome。IhavejusthadpigeonsandfowlsALIVEfromtheGambia！RabbitsandducksIamattendingtoprettycarefully，butlesssothanpigeons。Ifindmostremarkabledifferencesintheskeletonsofrabbits。Haveyoueverkeptanyoddbreedsofrabbits，andcanyougivemeanydetails？Oneotherquestion:Youusedtokeephawks;doyouatallknow，aftereatingabird，howsoonaftertheythrowupthepellet？
　　Nosubjectgivesmesomuchtroubleanddoubtanddifficultyasthemeansofdispersalofthesamespeciesofterrestrialproductionsontheoceanicislands。Landmolluscadrivememad，andIcannotanyhowgettheireggstoexperimentisetheirpoweroffloatingandresistancetotheinjuriousactionofsaltwater。Iwillnotapologiseforwritingsomuchaboutmyowndoings，asIbelieveyouwillliketohear。Dosometime，Ibegyou，letmehearhowyougetoninhealth;andIFSOINCLINED，letmehavesomewordsoncall—ducks。
　　MydearFox，yoursaffectionately，CH。DARWIN。
　　[Withregardtohisbookhewrote（November10th）toSirCharlesLyell:
　　"Iamworkingverysteadilyatmybigbook;Ihavefounditquiteimpossibletopublishanypreliminaryessayorsketch;butamdoingmyworkascompletelyasmypresentmaterialsallowwithoutwaitingtoperfectthem。AndthismuchaccelerationIowetoyou。"]
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，Sunday[October1856]。
　　MydearHooker，Theseedsarecomeallsafe，manythanksforthem。IwasverysorrytorunawaysosoonandmissanypartofmyMOSTpleasantevening;andIranawaylikeaGothandVandalwithoutwishingMrs。Hookergood—bye;butIwasonlyjustintime，asIgotontheplatformthetrainhadarrived。
　　Iwasparticularlygladofourdiscussionafterdinner，fightingabattlewithyoualwaysclearsmymindwonderfully。IgroantohearthatA。GrayagreeswithyouabouttheconditionofBotanicalGeography。AllIknowisthatifyouhadhadtosearchforlightinZoologicalGeographyyouwouldbycontrast，respectyourownsubjectavastdealmorethanyounowdo。
　　Thehawkshavebehavedlikegentlemen，andhavecastuppelletswithlotsofseedsinthem;andIhavejusthadaparcelofpartridge’sfeetwellcakedwithmud！！！（Themudinsuchcasesoftencontainsseeds，sothatplantsarethustransported。）Adios。
　　Yourinsaneandperversefriend，C。DARWIN。
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，November4th[1856]。
　　MydearHooker，IthankyoumoreCORDIALLYthanyouwillthinkprobable，foryournote。
　　Yourverdict（OntheMS。relatingtogeographicaldistribution。）hasbeenagreatrelief。OnmyhonourIhadnoideawhetherornotyouwouldsayitwas（andIknewyouwouldsayitverykindly）sobad，thatyouwouldhavebeggedmetohaveburntthewhole。TomyownmindmyMS。relievedmeofsomefewdifficulties，andthedifficultiesseemedtomeprettyfairlystated，butIhadbecomesobewilderedwithconflictingfacts，evidence，reasoningandopinions，thatIfelttomyselfthatIhadlostalljudgment。
　　YourgeneralverdictisINCOMPARABLYmorefavourablethanIhadanticipated……
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，November23rd[1856]。
　　MydearHooker，IfearIshallwearyyouwithletters，butdonotanswerthis，forintruthandwithoutflattery，Isovalueyourletters，thatafteraheavybatch，asoflate，IfeelthatIhavebeenextravagantandhavedrawntoomuchmoney，andshallthereforehavetostintmyselfonanotheroccasion。
　　WhenIsentmyMS。Ifeltstronglythatsomepreliminaryquestionsonthecausesofvariationoughttohavebeensentyou。WhetherIamrightorwronginthesepointsisquiteaseparatequestion，buttheconclusionwhichIhavecometo，quiteindependentlyofgeographicaldistribution，isthatexternalconditions（towhichnaturalistssooftenappeal）dobythemselvesVERYLITTLE。HowmuchtheydoisthepointofallothersonwhichIfeelmyselfveryweak。Ijudgefromthefactsofvariationunderdomestication，andImayyetgetmorelight。Butatpresent，afterdrawinguparoughcopyonthissubject，myconclusionisthatexternalconditionsdoEXTREMELYlittle，exceptincausingmerevariability。Thismerevariability（causingthechildNOTcloselytoresembleitsparent）IlookatasVERYdifferentfromtheformationofamarkedvarietyornewspecies。
　　（Nodoubtthevariabilityisgovernedbylaws，someofwhichIamendeavouringveryobscurelytotrace。）TheformationofastrongvarietyorspeciesIlookaasalmostwhollyduetotheselectionofwhatmaybeincorrectlycalledCHANCEvariationsorvariability。Thispowerofselectionstandsinthemostdirectrelationtotime，andinthestateofnaturecanbeonlyexcessivelyslow。Again，theslightdifferencesselected，bywhicharaceorspeciesisatlastformed，stands，asIthinkcanbeshown（evenwithplants，andobviouslywithanimals），inafarmoreimportantrelationtoitsassociatesthantoexternalconditions。
　　Therefore，accordingtomyprinciples，whetherrightorwrong，Icannotagreewithyourpropositionthattime，andalteredconditions，andalteredassociates，are’convertibleterms。’IlookatthefirstandthelastasFARmoreimportant:timebeingimportantonlysofarasgivingscopetoselection。GodknowswhetheryouwillperceiveatwhatIamdriving。I
　　shallhavetodiscussandthinkmoreaboutyourdifficultyofthetemperateandsub—arcticformsintheS。hemispherethanIhaveyetdone。ButIaminclinedtothinkthatIamright（ifmygeneralprinciplesareright），thattherewouldbelittletendencytotheformationofanewspecies，duringtheperiodofmigration，whethershorterorlonger，thoughconsiderablevariabilitymayhavesupervened……
　　CHARLESDARWINTOJ。D。HOOKER。
　　December24th[1856]……HowIdowishIlivednearyoutodiscussmatterswith。Ihavejustbeencomparingdefinitionsofspecies，andstatingbrieflyhowsystematicnaturalistsworkouttheirsubjects。AquilegiaintheFloraIndicawasacapitalexampleforme。Itisreallylaughabletoseewhatdifferentideasareprominentinvariousnaturalists’minds，whentheyspeakof"species;"
　　insome，resemblanceiseverythinganddescentoflittleweight——insome，resemblanceseemstogofornothing，andCreationthereigningidea——insome，descentisthekey，——insome，sterilityanunfailingtest，withothersitisnotworthafarthing。Itallcomes，Ibelieve，fromtryingtodefinetheundefinable。Isupposeyouhavelosttheoddblackseedfromthebirds’dung，whichgerminated，——anyhow，itisnotworthtakingtroubleover。Ihavenowgotaboutadozenseedsoutofsmallbirds’dung。Adios，MydearHooker，everyours，C。DARWIN。
　　CHARLESDARWINTOASAGRAY。
　　Down，January1st[1857？]。
　　MydearDrGray，Ihavereceivedthesecondpartofyourpaper（’StatisticsoftheFloraoftheNorthernUnitedStates。’"Silliman’sJournal"，1857。），andthoughI
　　havenothingparticulartosay，Imustsendyoumythanksandheartyadmiration。Thewholepaperstrikesmeasquiteexhaustingthesubject，andIquitefancyandflattermyselfInowappreciatethecharacterofyourFlora。WhatadifferenceinregardtoEuropeyourremarkinrelationtothegeneramakes！Ihavebeeneminentlygladtoseeyourconclusioninregardtothespeciesoflargegenerawidelyranging;itisinstrictconformitywiththeresultsIhaveworkedoutinseveralways。Itisofgreatimportancetomynotions。BythewayyouhavepaidmeaGREAT
　　compliment（"Fromsomeinvestigationsofhisown，thissagaciousnaturalistinclinestothinkthat[thespeciesof]largegenerarangeoveralargerareathanthespeciesofsmallgenerado。"——AsaGray，loc。cit。）:tobeSIMPLYmentionedeveninsuchapaperIconsideraverygreathonour。Oneofyourconclusionsmakesmegroan，viz。，thatthelineofconnectionofthestrictlyalpineplantsisthroughGreenland。IshouldEXTREMELYliketoseeyourreasonspublishedindetail，forit"riles"me（thisisaproperexpression，isitnot？）dreadfully。Lyelltoldme，thatAgassizhavingatheoryaboutwhenSaurianswerefirstcreated，onhearingsomecarefulobservationsopposedtothis，saidhedidnotbelieveit，"forNatureneverlied。"Iamjustinthispredicament，andrepeattoyouthat，"Natureneverlies，"ergo，theorisersarealwaysright……
　　Overworkedasyouare，IdaresayyouwillsaythatIamanodiousplague;
　　buthereisanothersuggestion！Iwasledbyoneofmywildspeculationstoconclude（thoughithasnothingtodowithgeographicaldistribution，yetithaswithyourstatistics）thattreeswouldhaveastrongtendencytohaveflowerswithdioecious，monoeciousorpolygamousstructure。SeeingthatthisseemedsoinPersoon，ItookonelittleBritishFlora，anddiscriminatingtreesfrombushesaccordingtoLoudon，Ihavefoundthattheresultwasinspecies，generaandfamilies，asIanticipated。SoIsentmynotionstoHookertoaskhimtotabulatetheNewZealandFloraforthisend，andhethoughtmyresultsufficientlycurious，todoso;andtheaccordancewithBritainisverystriking，andthemoreso，ashemadethreeclassesoftrees，bushes，andherbaceousplants。（HesaysfurtherheshallworktheTasmanianFloraonthesameprinciple。）Thebushesholdanintermediatepositionbetweentheothertwoclasses。Itseemstomeacuriousrelationinitself，andisverymuchso，ifmytheoryandexplanationarecorrect。（See’Origin，’Editioni。，page100。）
　　Withheartythanks，yourmosttroublesomefriend，C。DARWIN。
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，April12th[1857]。
　　MydearHooker，Yourletterhaspleasedmemuch，forInevercangetitoutofmyhead，thatItakeunfairadvantageofyourkindness，asIreceiveallandgivenothing。Whatasplendiddiscussionyoucouldwriteonthewholesubjectofvariation！Thecasesdiscussedinyourlastnotearevaluabletome（thoughodiousanddamnable），asshowinghowprofoundlyignorantweareonthecausesofvariation。Ishalljustalludetothesecases，asasortofsub—divisionofpolymorphismalittlemoredefinite，Ifancy，thanthevariationof，forinstance，theRubi，andequallyormoreperplexing。
　　IhavejustbeenputtingmynotestogetheronvariationsAPPARENTLYduetotheimmediateanddirectactionofexternalcauses;andIhavebeenstruckwithoneresult。Themostfirmsticklersforindependentcreationadmit，thatthefuroftheSAMEspeciesisthinnertowardsthesouthoftherangeofthesamespeciesthantothenorth——thattheSAMEshellsarebrighter—
　　colouredtothesouththannorth;thatthesame[shell]ispaler—colouredindeepwater——thatinsectsaresmalleranddarkeronmountains——morelividandtestaceousnearsea——thatplantsaresmallerandmorehairyandwithbrighterflowersonmountains:nowinallsuch，andothercases，distinctspeciesinthetwozonesfollowthesamerule，whichseemstometobemostsimplyexplainedbyspecies，beingonlystronglymarkedvarieties，andthereforefollowingthesamelawsasrecognisedandadmittedvarieties。I
　　mentionallthisonaccountofthevariationofplantsinascendingmountains;Ihavequotedtheforegoingremarkonlygenerallywithnoexamples，forIadd，thereissomuchdoubtanddisputewhattocallvarieties;butyetIhavestumbledonsomanycasualremarksonVARIETIES
　　ofplantsonmountainsbeingsocharacterised，thatIpresumethereissometruthinit。Whatthinkyou？DoyoubelievethereisANYtendencyinVARIETIES，asGENERALLYso—called，ofplantstobecomemorehairyandwithproportionallylargerandbrighter—colouredflowersinascendingamountain？
　　Ihavebeeninterestedinmy"weedgarden，"of3x2feetsquare:Imarkeachseedlingasitappears，andIamastonishedatthenumberthatcomeup，andstillmoreatthenumberkilledbyslugs，etc。Already59havebeensokilled;Iexpectedagoodmany，butIhadfanciedthatthiswasalesspotentcheckthanitseemstobe，andIattributedalmostexclusivelytomerechoking，thedestructionoftheseedlings。Grass—seedlingsseemtosuffermuchlessthanexogens……
　　CHARLESDARWINTOJ。D。HOOKER。
　　MoorPark，Farnham[April（？）1857]。
　　MydearHooker，Yourletterhasbeenforwardedtomehere，whereIamundergoinghydropathyforafortnight，havingbeenhereaweek，andhavingalreadyreceivedanamountofgoodwhichisquiteincredibletomyselfandquiteunaccountable。
　　IcanwalkandeatlikeaheartyChristian，andevenmynightsaregood。I
　　cannotintheleastunderstandhowhydropathycanactasitcertainlydoesonme。Itdullsone’sbrainsplendidly;Ihavenotthoughtaboutasinglespeciesofanykindsinceleavinghome。Yournotehastakenmeaback;I
　　thoughtthehairiness，etc。，ofAlpineSPECIESwasgenerallyadmitted;IamsureIhaveseenitalludedtoascoreoftimes。Falconerwasharanguingonittheotherdaytome。MeyenorGay，orsomesuchfellow（whomyouwoulddespise），Iremember，makessomeremarkonChilianCordilleraplants。
　　Wimmerhaswrittenalittlebookonthesamelines，andonVARIETIESbeingsocharacterisedintheAlps。Butafterwritingtoyou，IconfessIwasstaggeredbyfindingoneman（Moquin—Tandon，Ithink）sayingthatAlpineflowersarestronglyinclinedtobewhite，andLinnaeussayingthatcoldmakesplantsAPETALOUS，eventhesamespecies！AreArcticplantsoftenapetalous？Mygeneralbelieffrommycompilingworkisquitetoagreewithwhatyousayaboutthelittledirectinfluenceofclimate;andIhavejustalludedtothehairinessofAlpineplantsasanEXCEPTION。TheodoriferousnesswouldbeagoodcaseformeifIknewofVARIETIESbeingmoreodoriferousindryhabitats。
　　IfearthatIhavelookedatthehairinessofAlpineplantsassogenerallyacknowledgedthatIhavenotmarkedpassages，soasatalltoseewhatkindofevidenceauthorsadvance。Imustconfess，theotherday，whenIaskedFalconer，whetherheknewofINDIVIDUALplantslosingoracquiringhairinesswhentransported，hedidnot。ButnowTHISSECOND，mymemoryflashesonme，andIamcertainIhavesomewheregotmarkedacaseofhairyplantsfromthePyreneeslosinghairswhencultivatedatMontpellier。
　　ShallyouthinkmeveryimpudentifItellyouthatIhavesometimesthoughtthat（quiteindependentlyofthepresentcase），youarealittletoohardonbadobservers;thataremarkmadebyabadobserverCANNOTberight;anobserverwhodeservestobedamnedyouwouldutterlydamn。I
　　feelentiredeferencetoanyremarkyoumakeoutofyourownhead;butwheninoppositiontosomepoordevil，Isomehowinvoluntarilyfeelnotquitesomuch，butyetmuchdeferenceforyouropinion。Idonotknowintheleastwhetherthereisanytruthinthismycriticismagainstyou，butIhaveoftenthoughtIwouldtellyouit。
　　Iamreallyverymuchobligedforyourletter，for，thoughIintendedtoputonlyonesentenceandthatvaguely，Ishouldprobablyhaveputthatmuchtoostrongly。
　　Ever，mydearHooker，yoursmosttruly，C。DARWIN。
　　P。S。Thisnote，asyousee，hasnotanythingrequiringananswer。
　　Thedistributionoffresh—watermolluscshasbeenahorridincubustome，butIthinkIknowmywaynow;whenfirsthatchedtheyareveryactive，andIhavehadthirtyorfortycrawlonadeadduck’sfoot;andtheycannotbejerkedoff，andwilllivefifteenandeventwenty—fourhoursoutofwater。
　　[ThefollowingletterreferstotheexpeditionoftheAustrianfrigate"Novara";Lyellhadaskedmyfatherforsuggestions。]
　　CHARLESDARWINTOC。LYELL。
　　Down，February11th[1857]。
　　MydearLyell，IwasgladtoseeinthenewspapersabouttheAustrianExpedition。IhavenothingtoaddgeologicallytomynotesintheManual。（Thearticle"Geology"intheAdmiraltyManualofScientificEnquiry。）IdonotknowwhethertheExpeditionistieddowntocallatonlyfixedspots。Butiftherebeanychoiceorpowerinthescientificmentoinfluencetheplaces——thiswouldbemostdesirable。Itismymostdeliberateconvictionthatnothingwouldaidmore，NaturalHistory，thancarefulcollectingandinvestigatingALLTHEPRODUCTIONSofthemostisolatedislands，especiallyofthesouthernhemisphere。ExceptTristand’AcunhaandKerguelenLand，theyareveryimperfectlyknown;andevenatKerguelenLand，howmuchthereistomakeoutaboutthelignitebeds，andwhethertherearesignsofoldGlacialaction。Everyseashellandinsectandplantisofvaluefromsuchspots。SomeoneintheExpeditionespeciallyoughttohaveHooker’sNewZealandEssay。WhatgrandworktoexploreRodriguez，withitsfossilbirds，andlittleknownproductionsofeverykind。AgaintheSeychelles，which，withtheCocossonear，mustbearemnantofsomeolderland。TheouterislandofJuanFernandezislittleknown。Theinvestigationoftheselittlespotsbyabandofnaturalistswouldbegrand;St。Paul’sandAmsterdamwouldbeglorious，botanically，andgeologically。Canyounotrecommendthemtogetmy’Journal’and’VolcanicIslands’onaccountoftheGalapagos。IftheycomefromthenorthitwillbeashameandasiniftheydonotcallatCocosIslet，oneoftheGalapagos。IalwaysregrettedthatIwasnotabletoexaminethegreatcratersonAlbemarleIsland，oneoftheGalapagos。InNewZealandurgeonthemtolookoutforerraticbouldersandmarksofoldglaciers。
　　UrgetheuseofthedredgeintheTropics;howlittleornothingweknowofthelimitoflifedownwardinthehotseas？
　　Mypresentworkleadsmetoperceivehowmuchthedomesticanimalshavebeenneglectedinoutofthewaycountries。
　　TheRevillagigedoIslandoffMexico，Ibelieve，hasneverbeentroddenbyfootofnaturalist。
　　IftheexpeditionstickstosuchplacesasRio，CapeofGoodHope，CeylonandAustralia，etc。，itwillnotdomuch。
　　Everyoursmosttruly，C。DARWIN。
　　[ThefollowingpassageoccursinalettertoMr。Fox，February22，1857，andhasreferencetothebookonEvolutiononwhichhewasstillatwork。
　　Theremainderoftheletterismadeupindetailsofnointerest:
　　"Iamgotmostdeeplyinterestedinmysubject;thoughIwishIcouldsetlessvalueonthebaublefame，eitherpresentorposthumous，thanIdo，butnotIthink，toanyextremedegree:yet，ifIknowmyself，Iwouldworkjustashard，thoughwithlessgusto，ifIknewthatmybookwouldbepublishedforeveranonymously。"]
　　CHARLESDARWINTOA。R。WALLACE。
　　MoorPark，May1st，1857。
　　MydearSir，IammuchobligedforyourletterofOctober10th，fromCelebes，receivedafewdaysago;inalaboriousundertaking，sympathyisavaluableandrealencouragement。Byyourletterandevenstillmorebyyourpaper（’Onthelawthathasregulatedtheintroductionofnewspecies。’——Ann。Nat。Hist。，1855。）intheAnnals，ayearormoreago，Icanplainlyseethatwehavethoughtmuchalikeandtoacertainextenthavecometosimilarconclusions。InregardtothePaperintheAnnals，Iagreetothetruthofalmosteverywordofyourpaper;andIdaresaythatyouwillagreewithmethatitisveryraretofindoneselfagreeingprettycloselywithanytheoreticalpaper;foritislamentablehoweachmandrawshisowndifferentconclusionsfromtheverysamefacts。Thissummerwillmakethe20thyear（！）sinceIopenedmyfirstnote—book，onthequestionhowandinwhatwaydospeciesandvarietiesdifferfromeachother。Iamnowpreparingmyworkforpublication，butIfindthesubjectsoverylarge，thatthoughIhavewrittenmanychapters，IdonotsupposeIshallgotopressfortwoyears。IhaveneverheardhowlongyouintendstayingintheMalayArchipelago;IwishImightprofitbythepublicationofyourTravelstherebeforemyworkappears，fornodoubtyouwillreapalargeharvestoffacts。Ihaveactedalreadyinaccordancewithyouradviceofkeepingdomesticvarieties，andthoseappearinginastateofnature，distinct;butIhavesometimesdoubtedofthewisdomofthis，andthereforeIamgladtobebackedbyyouropinion。Imustconfess，however，Iratherdoubtthetruthofthenowveryprevalentdoctrineofallourdomesticanimalshavingdescendedfromseveralwildstocks;thoughIdonotdoubtthatitissoinsomecases。Ithinkthereisratherbetterevidenceonthesterilityofhybridanimalsthanyouseemtoadmit:andinregardtoplantsthecollectionofcarefullyrecordedfactsbyKolreuterandGaertner（andHerbert，）isENORMOUS。Imostentirelyagreewithyouonthelittleeffectsof"climatalconditions，"whichoneseesreferredtoadnauseaminallbooks:Isupposesomeverylittleeffectmustbeattributedtosuchinfluences，butIfullybelievethattheyareveryslight。ItisreallyIMPOSSIBLEtoexplainmyviews（inthecompassofaletter），onthecausesandmeansofvariationinastateofnature;butIhaveslowlyadoptedadistinctandtangibleidea，——whethertrueorfalseothersmustjudge;forthefirmestconvictionofthetruthofadoctrinebyitsauthor，seems，alas，nottobetheslightestguaranteeoftruth！……
　　CHARLESDARWINTOJ。D。HOOKER。
　　MoorPark，Saturday[May2nd，1857]。
　　MydearHooker，YouhaveshavedthehairofftheAlpineplantsprettyeffectually。ThecaseoftheAnthylliswillmakea"tie"withthebelievedcaseofPyreneesplantsbecomingglabrousatlowlevels。IfIDOfindthatIhavemarkedsuchfacts，Iwilllaytheevidencebeforeyou。Iwonderhowthebeliefcouldhaveoriginated！Wasitthroughfinalcausestokeeptheplantswarm？FalconerintalkcoupledthetwofactsofwoollyAlpineplantsandmammals。HowcandidlyandmeeklyyoutookmyJeremiadonyourseveritytosecond—classmen。AfterIhadsentitoff，anuglylittlevoiceaskedme，onceortwice，howmuchofmynobledefenceofthepoorinspiritandinfact，wasowingtoyourhavingnotseldomsmashedfavouritenotionsofmyown。Isilencedtheuglylittlevoicewithcontempt，butitwouldwhisperagainandagain。Isometimesdespisemyselfasapoorcompilerasheartilyasyoucoulddo，thoughIdoNOTdespisemywholework，asIthinkthereisenoughknowntolayafoundationforthediscussionontheoriginofspecies。Ihavebeenledtodespiseandlaughatmyselfasacompiler，forhavingputdownthat"Alpineplantshavelargeflowers，"andnowperhapsI
　　maywriteovertheseverywords，"Alpineplantshavesmallorapetalousflowers！"……
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，[May]16th[1857]。
　　MydearHooker，Yousaid——Ihopehonestly——thatyoudidnotdislikemyaskingquestionsongeneralpoints，youofcourseansweringornotastimeorinclinationmightserve。Ifindintheanimalkingdomthatthepropositionthatanypartororgandevelopednormally（i。e。，notamonstrosity）inaspeciesinanyHIGH
　　orUNUSUALdegree，comparedwiththesamepartororganinalliedspecies，tendstobeHIGHLYVARIABLE。Icannotdoubtthisfrommymassofcollectedfacts。Togiveaninstance，theCross—billisveryabnormalinthestructureofitsbillcomparedwithotheralliedFringillidae，andthebeakisEMINENTLYVARIABLE。TheHimantopus，remarkablefromthewonderfullengthofitslegs，isVERYvariableinthelengthofitslegs。IcouldgiveMANYmoststrikingandcuriousillustrationsinallclasses;somanythatIthinkitcannotbechance。ButIhaveNONEinthevegetablekingdom，owing，asIbelieve，tomyignorance。IfNepenthesconsistedofONEortwospeciesinagroupwithapitcherdeveloped，thenIshouldhaveexpectedittohavebeenveryvariable;butIdonotconsiderNepenthesacaseinpoint，forwhenawholegenusorgrouphasanorgan，howeveranomalous，Idonotexpectittobevariable，——itisonlywhenoneorfewspeciesdiffergreatlyinsomeonepartororganfromtheformsCLOSELY
　　ALLIEDtoitinallotherrespects，thatIbelievesuchpartororgantobehighlyvariable。Willyouturnthisinyourmind？ItisanimportantapparentLAW（！）forme。
　　Everyours，C。DARWIN。
　　P。S。——Idonotknowhowfaryouwillcaretohear，butIfindMoquin—Tandontreatsinhis’Teratologie’onvillosityofplants，andseemstoattributemoretodrynessthanaltitude;butseemstothinkthatitmustbeadmittedthatmountainplantsarevillose，andthatthisvillosityisonlyinpartexplainedbyDeCandolle’sremarkthatthedwarfedconditionofmountainplantswouldcondensethehairs，andsogivethemtheAPPEARANCEofbeingmorehairy。HequotesSenebier，’PhysiologieVegetale，’asauthority——I
　　supposethefirstauthority，formountainplantsbeinghairy。
　　IfIcouldshowpositivelythattheendemicspeciesweremorehairyindrydistricts，thenthecaseofthevarietiesbecomingmorehairyindrygroundwouldbeafactforme。
　　CHARLESDARWINTOJ。D。HOOKER。
　　Down，June3rd[1857]。
　　MydearHooker，Iamgoingtoenjoymyselfbyhavingaproseonmyownsubjectstoyou，andthisisagreaterenjoymenttomethanyouwillreadilyunderstand，asI
　　formonthstogetherdonotopenmymouthonNaturalHistory。Yourletterisofgreatvaluetome，andstaggersmeinregardtomyproposition。I
　　daresaytheabsenceofbotanicalfactsmayinpartbeaccountedforbythedifficultyofmeasuringslightvariations。Indeed，afterwriting，thisoccurredtome;forIhaveCrucianellastylosacomingintoflower，andthepistiloughttobeveryvariableinlength，andthinkingofthisIatoncefelthowcouldonejudgewhetheritwasvariableinanyhighdegree。Howdifferent，forinstance，fromthebeakofabird！ButIamnotsatisfiedwiththisexplanation，andamstaggered。YetIthinkthereissomethinginthelaw;Ihavehadsomanyinstances，asthefollowing:IwrotetoWollastontoaskhimtorunthroughtheMadeiraBeetlesandtellmewhetheranyonepresentedanythingveryanomalousinrelationtoitsallies。Hegavemeauniquecaseofanenormousheadinafemale，andthenIfoundinhisbook，alreadystated，thatthesizeoftheheadwasASTONISHINGLY