MydearHooker，Ihavebeendeeplyinterestedbyyourletter，andwehadagoodlaughoverHuxley’sremark，whichwassodeucedcleverthatyoucouldnotrecollectit。Icannotquitefollowyourtrainofthought，forinthelastpageyouadmitallthatIwish，havingapparentlydeniedall，orthoughtallmerewordsinthepreviouspagesofyournote;butitmaybemymuddle。IseeclearlythatanysatisfactionwhichPanmaygivewilldependontheconstitutionofeachman’smind。Ifyouhavearrivedalreadyatanysimilarconclusion，thewholewillofcourseappearstaletoyou。IheardyesterdayfromWallace，whosays（excusehorridvanity），"IcanhardlytellyouhowmuchIadmirethechapteron’Pangenesis。’ItisaPOSITIVE
　　COMFORTtometohaveanyfeasibleexplanationofadifficultythathasalwaysbeenhauntingme，andIshallneverbeabletogiveituptillabetteronesuppliesitsplace，andthatIthinkhardlypossible，etc。"Nowhisforegoing[italicised]wordsexpressmysentimentsexactlyandfully:
　　thoughperhapsIfeelthereliefextrastronglyfromhavingduringmanyyearsvainlyattemptedtoformsomehypothesis。WhenyouorHuxleysaythatasinglecellofaplant，orthestumpofanamputatedlimb，havethe"potentiality"ofreproducingthewhole——or"diffuseaninfluence，"thesewordsgivemenopositiveidea;——butwhenitissaidthatthecellsofaplant，orstump，includeatomsderivedfromeveryothercellofthewholeorganismandcapableofdevelopment，Igainadistinctidea。Butthisideawouldnotbewortharush，ifitappliedtoonecasealone;butitseemstometoapplytoalltheformsofreproduction——inheritance——metamorphosis——
　　totheabnormaltranspositionoforgans——tothedirectactionofthemaleelementonthemotherplant，etc。ThereforeIfullybelievethateachcelldoesACTUALLYthrowoffanatomorgemmuleofitscontents;——butwhetherornot，thishypothesisservesasausefulconnectinglinkforvariousgrandclassesofphysiologicalfacts，whichatpresentstandabsolutelyisolated。
　　Ihavetouchedonthedoubtfulpoint（alludedtobyHuxley）howfaratomsderivedfromthesamecellmaybecomedevelopedintodifferentstructureaccordinglyastheyaredifferentlynourished;Iadvancedasillustrationsgallsandpolypoidexcrescences……
　　Itisarealpleasuretometowritetoyouonthissubject，andIshouldbedelightedifwecanunderstandeachother;butyoumustnotletyourgoodnatureleadyouon。Remember，wealwaysfighttoothandnail。WegotoLondononTuesday，firstforaweektoQueenAnneStreet，andafterwardstoMissWedgwood’s，inRegent’sPark，andstaythewholemonth，which，asmygardenertrulysays，isa"terriblething"formyexperiments。
　　CHARLESDARWINTOW。OGLE。（Dr。WilliamOgle，nowtheSuperintendentofStatisticstotheRegistrar—General。）
　　Down，March6[1868]。
　　DearSir，Ithankyoumostsincerelyforyourletter，whichisveryinterestingtome。IwishIhadknownoftheseviewsofHippocratesbeforeIhadpublished，fortheyseemalmostidenticalwithmine——merelyachangeofterms——andanapplicationofthemtoclassesoffactsnecessarilyunknowntotheoldphilosopher。Thewholecaseisagoodillustrationofhowrarelyanythingisnew。
　　Hippocrateshastakenthewindoutofmysails，butIcareverylittleaboutbeingforestalled。Iadvancetheviewsmerelyasaprovisionalhypothesis，butwiththesecretexpectationthatsoonerorlatersomesuchviewwillhavetobeadmitted……Idonotexpectthereviewerswillbesolearnedasyou:otherwise，nodoubt，IshallbeaccusedofwilfullystealingPangenesisfromHippocrates，——forthisisthespiritsomereviewersdelighttoshow。
　　CHARLESDARWINTOVICTORCARUS。
　　Down，March21[1868]……IamverymuchobligedtoyouforsendingmesofranklyyouropiniononPangenesis，andIamsorryitisunfavourable，butIcannotquiteunderstandyourremarkonpangenesis，selection，andthestruggleforlifenotbeingmoremethodical。Iamnotatallsurprisedatyourunfavourableverdict;Iknowmany，probablymost，willcometothesameconclusion。OneEnglishReviewsaysitismuchtoocomplicated……Someofmyfriendsareenthusiasticonthehypothesis……SirC。Lyellsaystoeveryone，"youmaynotbelievein’Pangenesis，’butifyouonceunderstandit，youwillnevergetitoutofyourmind。"AndwiththiscriticismIamperfectlycontent。
　　Allcasesofinheritanceandreversionanddevelopmentnowappeartomeunderanewlight……
　　[AnextractfromalettertoFritzMuller，thoughoflaterdate（June），maybegivenhere:——
　　"YourletterofApril22hasmuchinterestedme。Iamdelightedthatyouapproveofmybook，forIvalueyouropinionmorethanthatofalmostanyone。IhaveyethopesthatyouwillthinkwellofPangenesis。Ifeelsurethatourmindsaresomewhatalike，andIfinditagreatrelieftohavesomedefinite，thoughhypotheticalview，whenIreflectonthewonderfultransformationsofanimals，——there—growthofparts，——andespeciallythedirectactionofpollenonthemother—form，etc。Itoftenappearstomealmostcertainthatthecharactersoftheparentsare"photographed"onthechild，onlybymeansofmaterialatomsderivedfromeachcellinbothparents，anddevelopedinthechild。"]
　　CHARLESDARWINTOASAGRAY。
　　Down，May8[1868]。
　　MydearGray，Ihavebeenamostungratefulandungraciousmannottohavewrittentoyouanimmensetimeagotothankyouheartilyforthe"Nation"，andforallyourmostkindaidinregardtotheAmericanedition[of’AnimalsandPlants’]。ButIhavebeenoflateoverwhelmedwithletters，whichIwasforcedtoanswer，andsoputoffwritingtoyou。ThismorningIreceivedtheAmericanedition（whichlookscapital），withyournicepreface，forwhichheartythanks。Ihopetoheaventhatthebookwillsucceedwellenoughtopreventyourepentingofyouraid。Thisarrivalhasputthefinishingstroketomyconscience，whichwillendureitswrongsnolonger……Yourarticleinthe"Nation"[March19]seemstomeverygood，andyougiveanexcellentideaofPangenesis——aninfantcherishedbyfewasyet，excepthistenderparent，butwhichwilllivealonglife。Thereisparentalpresumptionforyou！Yougiveagoodslapatmyconcludingmetaphor（AshortabstractoftheprecipicemetaphorisgiveninVolumeI。
　　Dr。Gray’scriticismonthispointisasfollows:"ButinMr。Darwin’sparallel，tomeetthecaseofnatureaccordingtohisownviewofit，notonlythefragmentsofrock（answeringtovariation）shouldfall，buttheedifice（answeringtonaturalselection）shouldrise，irrespectiveofwillorchoice！"Butmyfather’sparalleldemandsthatnaturalselectionshallbethearchitect，nottheedifice——thequestionofdesignonlycomesinwithregardtotheformofthebuildingmaterials。）:undoubtedlyIoughttohavebroughtinandcontrastednaturalandartificialselection;butitseemssoobvioustomethatnaturalselectiondependedoncontingenciesevenmorecomplexthanthosewhichmusthavedeterminedtheshapeofeachfragmentatthebaseofmyprecipice。WhatIwantedtoshowwasthatinreferencetopre—ordainmentwhateverholdsgoodintheformationofapouterpigeonholdsgoodintheformationofanaturalspeciesofpigeon。
　　Icannotseethatthisisfalse。Iftherightvariationsoccurred，andnoothers，naturalselectionwouldbesuperfluous。AreviewerinanEdinburghpaper，whotreatsmewithprofoundcontempt，saysonthissubjectthatProfessorAsaGraycouldwiththegreatesteasesmashmeintolittlepieces。（The"DailyReview"，April27，1868。Myfatherhasgivenratherahighlycolouredversionofthereviewer’sremarks:"WedoubtnotthatProfessorAsaGray……couldshowthatnaturalselection……issimplyaninstrumentinthehandsofanomnipotentandomniscientcreator。"Thereviewergoesontosaythatthepassageinquestionisa"verymelancholyone，"andthatthetheoryisthe"apotheosisofmaterialism。"）
　　Believeme，mydearGray，Yourungratefulbutsincerefriend，CHARLESDARWIN。
　　CHARLESDARWINTOG。BENTHAM。
　　Down，June23，1868。
　　MydearMr。Bentham，Asyouraddress（PresidentialAddresstotheLinneanSociety。）issomewhatofthenatureofaverdictfromajudge，Idonotknowwhetheritisproperformetodoso，butImustandwillthankyouforthepleasurewhichyouhavegivenme。Iamdelightedatwhatyousayaboutmybook。Igotsotiredofit，thatformonthstogetherIthoughtmyselfaperfectfoolforhavinggivenupsomuchtimeincollectingandobservinglittlefacts，butnowIdonotcareifascoreofcommoncriticsspeakascontemptuouslyofthebookasdidthe"Athenaeum"。Ifeeljustifiedinthis，forIhavesocompletearelianceonyourjudgmentthatIfeelcertainthatIshouldhavebowedtoyourjudgmenthaditbeenasunfavourableasitisthecontrary。
　　WhatyousayaboutPangenesisquitesatisfiesme，andisasmuchperhapsasanyoneisjustifiedinsaying。IhavereadyourwholeAddresswiththegreatestinterest。Itmusthavecostyouavastamountoftrouble。Withcordialthanks，praybelieveme，Yoursverysincerely，CH。DARWIN。
　　P。S。——IfearthatitisnotlikelythatyouhaveasuperfluouscopyofyourAddress;ifyouhave，IshouldmuchliketosendonetoFritzMullerintheinteriorofBrazil。BythewayletmeaddthatIdiscussedbud—variationchieflyfromabeliefwhichiscommontoseveralpersons，thatallvariabilityisrelatedtosexualgeneration;Iwishedtoshowclearlythatthiswasanerror。
　　[Theaboveseriesoflettersmayservetoshowtosomeextentthereceptionwhichthenewbookreceived。Beforepassingon（inthenextchapter）tothe’DescentofMan，’IgivealetterreferringtothetranslationofFritzMuller’sbook，’FurDarwin，’itwasoriginallypublishedin1864，buttheEnglishtranslation，byMr。Dallas，whichborethetitlesuggestedbySirC。Lyell，of’FactsandArgumentsforDarwin，’didnotappearuntil1869:]
　　CHARLESDARWINTOF。MULLER。
　　Down，March16[1868]。
　　MydearSir，Yourbrother，asyouwillhaveheardfromhim，feltsoconvincedthatyouwouldnotobjecttoatranslationof’FurDarwin’（InalettertoFritzMuller，myfatherwrote:——"Iamvexedtoseethatonthetitlemynameismoreconspicuousthanyours，whichIespeciallyobjectedto，andI
　　cautionedtheprintersafterseeingoneproof。"），thatIhaveventuredtoarrangeforatranslation。Engelmannhasveryliberallyofferedmeclichesofthewoodcutsfor22thalers;Mr。Murrayhasagreedtobringoutatranslation（andheisourbestpublisher）oncommission，forhewouldnotundertaketheworkonhisownrisk;andIhaveagreedwithMr。W。S。Dallas（whohastranslatedVonSieboldonParthenogenesis，andmanyGermanworks，andwhowritesverygoodEnglish）totranslatethebook。Hethinks（andheisagoodjudge）thatitisimportanttohavesomefewcorrectionsoradditions，inordertoaccountforatranslationappearingsolately[i。e。
　　atsuchalongintervaloftime]aftertheoriginal;sothatIhopeyouwillbeabletosendsome……
　　[TwolettersmaybeplacedhereasbearingonthespreadofEvolutionaryideasinFranceandGermany:]
　　CHARLESDARWINTOA。GAUDRY。
　　Down，January21[1868]。
　　DearSir，IthankyouforyourinterestingessayontheinfluenceoftheGeologicalfeaturesofthecountryonthemindandhabitsoftheAncientAthenians（ThisappearstorefertoM。Gaudry’spapertranslatedinthe’Geol。Mag。，’
　　1868，page372。），andforyourveryobligingletter。Iamdelightedtohearthatyouintendtoconsidertherelationsoffossilanimalsinconnectionwiththeirgenealogy;itwillaffordyouafinefieldfortheexerciseofyourextensiveknowledgeandpowersofreasoning。YourbeliefwillIsuppose，atpresent，loweryouintheestimationofyourcountrymen;
　　butjudgingfromtherapidspreadinallpartsofEurope，exceptingFrance，ofthebeliefinthecommondescentofalliedspecies，Imustthinkthatthisbeliefwillbeforelongbecomeuniversal。HowstrangeitisthatthecountrywhichgavebirthtoBuffon，theelderGeoffroy，andespeciallytoLamarck，shouldnowclingsopertinaciouslytothebeliefthatspeciesareimmutablecreations。
　　MyworkonVariation，etc。，underdomestication，willappearinaFrenchtranslationinafewmonths’time，andIwilldomyselfthepleasureandhonourofdirectingthepublishertosendacopytoyoutothesameaddressasthisletter。
　　Withsincererespect，Iremain，dearsir，Yoursveryfaithfully，CHARLESDARWIN。
　　[Thenextletterisofespecialinterest，asshowinghowhighavaluemyfatherplacedonthesupportoftheyoungerGermannaturalists:]
　　CHARLESDARWINTOW。PREYER。（NowProfessorofPhysiologyatJena。）
　　March31，1868……IamdelightedtohearthatyouupholdthedoctrineoftheModificationofSpecies，anddefendmyviews。ThesupportwhichIreceivefromGermanyismychiefgroundforhopingthatourviewswillultimatelyprevail。TothepresentdayIamcontinuallyabusedortreatedwithcontemptbywritersofmyowncountry;buttheyoungernaturalistsarealmostallonmyside，andsoonerorlaterthepublicmustfollowthosewhomakethesubjecttheirspecialstudy。Theabuseandcontemptofignorantwritershurtsmeverylittle……
　　CHAPTER2。VI。
　　WORKON’MAN。’
　　1864—1870。
　　[IntheautobiographicalchapterinVolumeI。，myfathergivesthecircumstanceswhichledtohiswritingthe’DescentofMan。’Hestatesthathiscollectionoffacts，begunin1837or1838，wascontinuedformanyyearswithoutanydefiniteideaofpublishingonthesubject。ThefollowinglettertoMr。Wallaceshowsthatintheperiodofill—healthanddepressionabout1864hedespairedofeverbeingabletodoso:]
　　CHARLESDARWINTOA。R。WALLACE。
　　Down，[May？]28[1864]。
　　DearWallace，IamsomuchbetterthatIhavejustfinishedapaperforLinneanSociety（Onthethreeforms，etc。，ofLythrum。）;butIamnotyetatallstrong，I
　　feltmuchdisinclinationtowrite，andthereforeyoumustforgivemefornothavingsoonerthankedyouforyourpaperon’Man’（’AnthropologicalReview，’March1864。），receivedonthe11th。ButfirstletmesaythatI
　　havehardlyeverinmylifebeenmorestruckbyanypaperthanthaton’Variation，’etc。etc。，inthe"Reader"。（’"Reader"，April16，1864。"OnthePhenomenaofVariation，"etc。AbstractofapaperreadbeforetheLinneanSociety，March17，1864。）IfeelsurethatsuchpaperswilldomoreforthespreadingofourviewsonthemodificationofspeciesthananyseparateTreatisesonthesimplesubjectitself。Itisreallyadmirable;
　　butyououghtnotintheManpapertospeakofthetheoryasmine;itisjustasmuchyoursasmine。Onecorrespondenthasalreadynoticedtomeyour"high—minded"conductonthishead。ButnowforyourManpaper，aboutwhichIshouldliketowritemorethanIcan。Thegreatleadingideaisquitenewtome，viz。thatduringlateages，themindwillhavebeenmodifiedmorethanthebody;yetIhadgotasfarastoseewithyouthatthestrugglebetweentheracesofmandependedentirelyonintellectualandMORALqualities。ThelatterpartofthepaperIcandesignateonlyasgrandandmosteloquentlydone。Ihaveshownyourpapertotwoorthreepersonswhohavebeenhere，andtheyhavebeenequallystruckwithit。I
　　amnotsurethatIgowithyouonallminorpoints:whenreadingSirG。
　　Grey’saccountoftheconstantbattlesofAustraliansavages，Irememberthinkingthatnaturalselectionwouldcomein，andlikewisewiththeEsquimaux，withwhomtheartoffishingandmanagingcanoesissaidtobehereditary。Iratherdifferontherank，underaclassificatorypointofview，whichyouassigntoman;Idonotthinkanycharactersimplyinexcessoughtevertobeusedforthehigherdivisions。Antswouldnotbeseparatedfromotherhymenopterousinsects，howeverhightheinstinctoftheone，andhoweverlowtheinstinctsoftheother。Withrespecttothedifferencesofrace，aconjecturehasoccurredtomethatmuchmaybeduetothecorrelationofcomplexion（andconsequentlyhair）withconstitution。
　　Assumethataduskyindividualbestescapedmiasma，andyouwillreadilyseewhatImean。IpersuadedtheDirector—GeneraloftheMedicalDepartmentoftheArmytosendprintedformstothesurgeonsofallregimentsintropicalcountriestoascertainthispoint，butIdaresayI
　　shallnevergetanyreturns。Secondly，Isuspectthatasortofsexualselectionhasbeenthemostpowerfulmeansofchangingtheracesofman。I
　　canshowthatthedifferentraceshaveawidelydifferentstandardofbeauty。Amongsavagesthemostpowerfulmenwillhavethepickofthewomen，andtheywillgenerallyleavethemostdescendants。Ihavecollectedafewnotesonman，butIdonotsupposethatIshalleverusethem。Doyouintendtofollowoutyourviews，andifso，wouldyoulikeatsomefuturetimetohavemyfewreferencesandnotes？IamsureIhardlyknowwhethertheyareofanyvalue，andtheyareatpresentinastateofchaos。
　　ThereismuchmorethatIshouldliketowrite，butIhavenotstrength。
　　Believeme，dearWallace，yoursverysincerely，CH。DARWIN。
　　P。S。——Ouraristocracyishandsomer（morehideousaccordingtoaChineseorNegro）thanthemiddleclasses，from（havingthe）pickofthewomen;butoh，whataschemeisprimogeniturefordestroyingnaturalselection！I
　　fearmyletterwillbebarelyintelligibletoyou。
　　[InFebruary1867，whenthemanuscriptof’AnimalsandPlants’hadbeensenttoMessrs。Clowestobeprinted，andbeforetheproofsbegantocomein，hehadanintervalofsparetime，andbegana"chapteronMan，"buthesoonfounditgrowingunderhishands，anddeterminedtopublishitseparatelyasa"verysmallvolume。"
　　Theworkwasinterruptedbythenecessityofcorrectingtheproofsof’AnimalsandPlants，’andbysomebotanicalwork，butwasresumedinthefollowingyear，1868，themomenthecouldgivehimselfuptoit。
　　Herecognizedwithregretthegradualchangeinhismindthatrenderedcontinuousworkmoreandmorenecessarytohimashegrewolder。ThisisexpressedinalettertoSirJ。D。Hooker，June17，1868，whichrepeatstosomeextentwhatisexpressedintheAutobiography:——
　　"Iamgladyouwereatthe’Messiah，’itistheonethingthatIshouldliketohearagain，butIdaresayIshouldfindmysoultoodrieduptoappreciateitasinolddays;andthenIshouldfeelveryflat，foritisahorridboretofeelasIconstantlydo，thatIamawitheredleafforeverysubjectexceptScience。ItsometimesmakesmehateScience，thoughGodknowsIoughttobethankfulforsuchaperennialinterest，whichmakesmeforgetforsomehourseverydaymyaccursedstomach。"
　　TheworkonManwasinterruptedbyillnessintheearlysummerof1868，andhelefthomeonJuly16thforFreshwater，intheIsleofWight，whereheremainedwithhisfamilyuntilAugust21st。HerehemadetheacquaintanceofMrs。Cameron。Shereceivedthewholefamilywithopen—heartedkindnessandhospitality，andmyfatheralwaysretainedawarmfeelingoffriendshipforher。Shemadeanexcellentphotographofhim，whichwaspublishedwiththeinscriptionwrittenbyhim:"Ilikethisphotographverymuchbetterthananyotherwhichhasbeentakenofme。"Furtherinterruptionoccurredintheautumnsothatcontinuousworkonthe’DescentofMan’didnotbeginuntil1869。Thefollowinglettersgivesomeideaoftheearlierworkin1867:]
　　CHARLESDARWINTOA。R。WALLACE。
　　Down，February22，[1867？]。
　　MydearWallace，Iamhardatworkonsexualselection，andamdrivenhalfmadbythenumberofcollateralpointswhichrequireinvestigation，suchastherelativenumberofthetwosexes，andespeciallyonpolygamy。Canyouaidmewithrespecttobirdswhichhavestronglymarkedsecondarysexualcharacters，suchasbirdsofparadise，humming—birds，theRupicola，oranyothersuchcases？Manygallinaceousbirdscertainlyarepolygamous。Isupposethatbirdsmaybeknownnottobepolygamousiftheyareseenduringthewholebreedingseasontoassociateinpairs，orifthemaleincubatesoraidsinfeedingtheyoung。Willyouhavethekindnesstoturnthisinyourmind？
　　Butitisashametotroubleyounowthat，asIamHEARTILYgladtohear，youareatworkonyourMalayantravels。Iamfearfullypuzzledhowfartoextendyourprotectiveviewswithrespecttothefemalesinvariousclasses。ThemoreIworkthemoreimportantsexualselectionapparentlycomesout。
　　Canbutterfliesbepolygamous！i。e。willonemaleimpregnatemorethanonefemale？Forgivemetroublingyou，andIdaresayIshallhavetoaskforgivenessagain……
　　CHARLESDARWINTOA。R。WALLACE。
　　Down，February23[1867]。
　　DearWallace，ImuchregrettedthatIwasunabletocallonyou，butafterMondayIwasunableeventoleavethehouse。OnMondayeveningIcalledonBates，andputadifficultybeforehim，whichhecouldnotanswer，and，asonsomeformersimilaroccasion，hisfirstsuggestionwas，"YouhadbetteraskWallace。"Mydifficultyis，whyarecaterpillarssometimessobeautifullyandartisticallycoloured？Seeingthatmanyarecolouredtoescapedanger，Icanhardlyattributetheirbrightcolourinothercasestomerephysicalconditions。BatessaysthemostgaudycaterpillarheeversawinAmazonia（ofasphinx）wasconspicuousatthedistanceofyards，fromitsblackandredcolours，whilstfeedingonlargegreenleaves。Ifanyoneobjectedtomalebutterflieshavingbeenmadebeautifulbysexualselection，andaskedwhyshouldtheynothavebeenmadebeautifulaswellastheircaterpillars，whatwouldyouanswer？Icouldnotanswer，butshouldmaintainmyground。
　　Willyouthinkoverthis，andsometime，eitherbyletterorwhenwemeet，tellmewhatyouthink？AlsoIwanttoknowwhetheryourFEMALEmimeticbutterflyismorebeautifulandbrighterthanthemale。WhennextinLondonImustgetyoutoshowmeyourkingfishers。Myhealthisadreadfulevil;IfailedinhalfmyengagementsduringthislastvisittoLondon。
　　Believeme，yoursverysincerely，C。DARWIN。
　　CHARLESDARWINTOA。R。WALLACE。
　　Down，February26[1867]。
　　MydearWallace，Bateswasquiteright;youarethemantoapplytoinadifficulty。I
　　neverheardanythingmoreingeniousthanyoursuggestion（Thesuggestionthatconspicuouscaterpillarsorperfectinsects（e。g。whitebutterflies），whicharedistastefultobirds，areprotectedbybeingeasilyrecognisedandavoided。SeeMr。Wallace’s’NaturalSelection，’2ndedition，page117。），andIhopeyoumaybeabletoproveittrue。Thatisasplendidfactaboutthewhitemoths;itwarmsone’sverybloodtoseeatheorythusalmostprovedtobetrue。（Mr。JennerWeir’sobservationspublishedintheTransactionsoftheEntomolog。Soc。（1869and1870）givestrongsupporttothetheoryinquestion。）Withrespecttothebeautyofmalebutterflies，I
　　mustasyetthinkitisduetosexualselection。Thereissomeevidencethatdragon—fliesareattractedbybrightcolours;butwhatleadsmetotheabovebeliefis，somanymaleOrthopteraandCicadashavingmusicalinstruments。Thisbeingthecase，theanalogyofbirdsmakesmebelieveinsexualselectionwithrespecttocolourininsects。IwishIhadstrengthandtimetomakesomeoftheexperimentssuggestedbyyou，butIthoughtbutterflieswouldnotpairinconfinement。IamsureIhaveheardofsomesuchdifficulty。ManyyearsagoIhadadragon—flypaintedwithgorgeouscolours，butIneverhadanopportunityoffairlytryingit。
　　Thereasonofmybeingsomuchinterestedjustatpresentaboutsexualselectionis，thatIhavealmostresolvedtopublishalittleessayontheoriginofMankind，andIstillstronglythink（thoughIfailedtoconvinceyou，andthis，tome，istheheaviestblowpossible）thatsexualselectionhasbeenthemainagentinformingtheracesofman。
　　Bytheway，thereisanothersubjectwhichIshallintroduceinmyessay，namely，expressionofcountenance。Now，doyouhappentoknowbyanyoddchanceaverygood—naturedandacuteobserverintheMalayArchipelago，whoyouthinkwouldmakeafeweasyobservationsformeontheexpressionoftheMalayswhenexcitedbyvariousemotions？ForinthiscaseIwouldsendtosuchpersonalistofqueries。Ithankyouforyourmostinterestingletter，andremain，Yoursverysincerely，CH。DARWIN。
　　CHARLESDARWINTOA。R。WALLACE。
　　Down，March[1867]。
　　MydearWallace，Ithankyoumuchforyourtwonotes。ThecaseofJuliaPastrana（Abeardedwomanhavinganirregulardoublesetofteeth。’AnimalsandPlants，’
　　volumeii。page328。）isasplendidadditiontomyothercasesofcorrelatedteethandhair，andIwilladditincorrectingthepressofmypresentvolume。Prayletmehearinthecourseofthesummerifyougetanyevidenceaboutthegaudycaterpillars。Ishouldmuchliketogive（orquoteifpublished）thisideaofyours，ifinanywaysupported，assuggestedbyyou。Itwill，however，bealongtimehence，forIcanseethatsexualselectionisgrowingintoquitealargesubject，whichIshallintroduceintomyessayonMan，supposingthatIeverpublishit。Ihadintendedgivingachapteronman，inasmuchasmanycallhim（notQUITE
　　truly）aneminentlydomesticatedanimal，butIfoundthesubjecttoolargeforachapter。NorshallIbecapableoftreatingthesubjectwell，andmysolereasonfortakingitupis，thatIamprettywellconvincedthatsexualselectionhasplayedanimportantpartintheformationofraces，andsexualselectionhasalwaysbeenasubjectwhichhasinterestedmemuch。IhavebeenverygladtoseeyourimpressionfrommemoryontheexpressionofMalays。Ifullyagreewithyouthatthesubjectisinnowayanimportantone;itissimplya"hobby—horse"withme，abouttwenty—sevenyearsold;andAFTERthinkingthatIwouldwriteanessayonman，itflashedonmethatIcouldworkinsome"supplementalremarksonexpression。"Afterthehorrid，tedious，dullworkofmypresenthuge，andIfearunreadable，book[’TheVariationofAnimalsandPlants’]，IthoughtIwouldamusemyselfwithmyhobby—horse。Thesubjectis，Ithink，morecuriousandmoreamenabletoscientifictreatmentthanyouseemwillingtoallow。Iwant，anyhow，toupsetSirC。Bell’sview，giveninhismostinterestingwork，’TheAnatomyofExpression，’thatcertainmuscleshavebeengiventomansolelythathemayrevealtoothermenhisfeelings。I
　　wanttotryandshowhowexpressionshavearisen。Thatisagoodsuggestionaboutnewspapers，butmyexperiencetellsmethatprivateapplicationsaregenerallymostfruitful。Iwill，however，seeifIcangetthequeriesinsertedinsomeIndianpaper。Idonotknowthenamesoraddressesofanyotherpapers……Mytwofemaleamanuensesarebusywithfriends，andIfearthisscrawlwillgiveyoumuchtroubletoread。Withmanythanks，Yoursverysincerely，CH。DARWIN。
　　[Thefollowinglettermaybeworthgiving，asanexampleofhissourcesofinformation，andasshowingwhatwerethethoughtsatthistimeoccupyinghim:]
　　CHARLESDARWINTOF。MULLER。
　　Down，February22[1867]……ManythanksforallthecuriousfactsabouttheunequalnumberofthesexesinCrustacea，butthemoreIinvestigatethissubjectthedeeperI
　　sinkindoubtanddifficulty。ThanksalsofortheconfirmationoftherivalryofCicadae。Ihaveoftenreflectedwithsurpriseonthediversityofthemeansforproducingmusicwithinsects，andstillmorewithbirds。
　　Wethusgetahighideaoftheimportanceofsongintheanimalkingdom。
　　PleasetotellmewhereIcanfindanyaccountoftheauditoryorgansintheOrthoptera。Yourfactsarequitenewtome。ScudderhasdescribedaninsectintheDevonianstrata，furnishedwithastridulatingapparatus。I
　　believeheistobetrusted，and，ifso，theapparatusisofastonishingantiquity。AfterreadingLandois’spaperIhavebeenworkingatthestridulatingorganintheLamellicornbeetles，inexpectationoffindingitsexual;butIhaveonlyfounditasyetintwocases，andintheseitwasequallydevelopedinbothsexes。Iwishyouwouldlookatanyofyourcommonlamellicorns，andtakeholdofbothmalesandfemales，andobservewhethertheymakethesqueakingorgratingnoiseequally。Iftheydonot，youcould，perhaps，sendmeamaleandfemaleinalightlittlebox。Howcuriousitisthatthereshouldbeaspecialorganforanobjectapparentlysounimportantassqueaking。Hereisanotherpoint;haveyouanytoucans？
　　ifso，askanytrustworthyhunterwhetherthebeaksofthemales，orofbothsexes，aremorebrightlycolouredduringthebreedingseasonthanatothertimesoftheyear……HeavenknowswhetherIshalleverlivetomakeuseofhalfthevaluablefactswhichyouhavecommunicatedtome！YourpaperonBalanusarmatus，translatedbyMr。Dallas，hasjustappearedinour’AnnalsandMagazineofNaturalHistory，’andIhavereaditwiththegreatestinterest。IneverthoughtthatIshouldlivetohearofahybridBalanus！Iamverygladthatyouhaveseenthecementtubes;theyappeartomeextremelycurious，and，asfarasIknow，youarethefirstmanwhohasverifiedmyobservationsonthispoint。
　　Withmostcordialthanksforallyourkindness，mydearSir，Yoursverysincerely，C。DARWIN。
　　CHARLESDARWINTOA。DECANDOLLE。
　　Down，July6，1868。
　　MydearSir，IreturnyoumySINCEREthanksforyourlongletter，whichIconsideragreatcompliment，andwhichisquitefullofmostinterestingfactsandviews。Yourreferencesandremarkswillbeofgreatuseshouldaneweditionofmybook（’VariationofAnimalsandPlants。’）bedemanded，butthisishardlyprobable，forthewholeeditionwassoldwithinthefirstweek，andanotherlargeeditionimmediatelyreprinted，whichIshouldthinkwouldsupplythedemandforever。YouaskmewhenIshallpublishonthe’VariationofSpeciesinaStateofNature。’IhavehadtheMS。foranothervolumealmostreadyduringseveralyears，butIwassomuchfatiguedbymylastbookthatIdeterminedtoamusemyselfbypublishingashortessayonthe’DescentofMan。’IwaspartlyledtodothisbyhavingbeentauntedthatIconcealedmyviews，butchieflyfromtheinterestwhichIhadlongtakeninthesubject。Nowthisessayhasbranchedoutintosomecollateralsubjects，andIsupposewilltakememorethanayeartocomplete。Ishallthenbeginon’Species，’butmyhealthmakesmeaveryslowworkman。Ihopethatyouwillexcusethesedetails，whichIhavegiventoshowthatyouwillhaveplentyoftimetopublishyourviewsfirst，whichwillbeagreatadvantagetome。Ofallthecuriousfactswhichyoumentioninyourletter，Ithinkthatofthestronginheritanceofthescalp—muscleshasinterestedmemost。Ipresumethatyouwouldnotobjecttomygivingthisverycuriouscaseonyourauthority。AsIbelieveallanatomistslookatthescalp—musclesasaremnantofthePanniculuscarnosuswhichiscommontoallthelowerquadrupeds，Ishouldlookattheunusualdevelopmentandinheritanceofthesemusclesasprobablyacaseofreversion。Yourobservationonsomanyremarkablemeninnoblefamilieshavingbeenillegitimateisextremelycurious;andshouldIevermeetanyonecapableofwritinganessayonthissubject，Iwillmentionyourremarksasagoodsuggestion。Dr。Hookerhasseveraltimesremarkedtomethatmoralsandpoliticswouldbeveryinterestingifdiscussedlikeanybranchofnaturalhistory，andthisisnearlytothesameeffectwithyourremarks……
　　CHARLESDARWINTOL。AGASSIZ。
　　Down，August19，1868。
　　DearSir，Ithankyoucordiallyforyourverykindletter。Icertainlythoughtthatyouhadformedsolowanopinionofmyscientificworkthatitmighthaveappearedindelicateinmetohaveaskedforinformationfromyou，butitneveroccurredtomethatmyletterwouldhavebeenshowntoyou。Ihaveneverforamomentdoubtedyourkindnessandgenerosity，andIhopeyouwillnotthinkitpresumptioninmetosay，thatwhenwemet，manyyearsago，attheBritishAssociationatSouthampton，Ifeltforyouthewarmestadmiration。
　　YourinformationontheAmazonianfisheshasinterestedmeEXTREMELY，andtellsmeexactlywhatIwantedtoknow。Iwasaware，throughnotesgivenmebyDr。Gunther，thatmanyfishesdifferedsexuallyincolourandothercharacters，butIwasparticularlyanxioustolearnhowfarthiswasthecasewiththosefishesinwhichthemale，differentlyfromwhatoccurswithmostbirds，takesthelargestshareinthecareoftheovaandyoung。Yourletterhasnotonlyinterestedmemuch，buthasgreatlygratifiedmeinotherrespects，andIreturnyoumysincerethanksforyourkindness。Praybelieveme，mydearSir，Yoursveryfaithfully，CHARLESDARWIN。