Soc。Bot。’1862page94。）;andtheseareplantswhichfloristsspeakofasnevercomingtruebyseed:butifcarebetakentopreventcrossing，neitherspeciesisbyanymeansveryinconstant，incolour;thusIraisedtwenty—threeplantsfromapurpleprimrose，fertilisedbyMr。J。Scottwithitspollen，andeighteencameuppurpleofdifferentshades，andonlyfiverevertedtotheordinaryyellowcolour:again，Iraisedtwentyplantsfromabright—redcowslip，similarlytreatedbyMr。Scott，andeveryoneperfectlyresembleditsparentincolour，aslikewisedid，withtheexceptionofasingleplant，72grandchildren。Evenwiththemostvariableflowers，itisprobablethateachdelicateshadeofcolourmightbepermanentlyfixedsoastobetransmittedbyseed，bycultivationinthesamesoil，bylong—continuedselection，andespeciallybythepreventionofcrosses。Iinferthisfromcertainannuallarkspurs（Delphiniumconsolidaandajacis），ofwhichcommonseedlingspresentagreaterdiversityofcolourthananyotherplantknowntome;yetonprocuringseedoffivenamedGermanvarietiesofD。consolida，onlynineplantsoutofninety—fourwerefalse;andtheseedlingsofsixvarietiesofD。ajacisweretrueinthesamemanneranddegreeaswiththestocksabovedescribed。A
distinguishedbotanistmaintainsthattheannualspeciesofDelphiniumarealwaysself—fertilised;thereforeImaymentionthatthirty—twoflowersonabranchofD。consolida，enclosedinanet，yieldedtwenty—sevencapsules，withanaverageof17。2seedineach;whilstfiveflowers，underthesamenet，whichwereartificiallyfertilised，inthesamemannerasmustbeeffectedbybeesduringtheirincessantvisits，yieldedfivecapsuleswithanaverageof35。2fineseed;andthisshowsthattheagencyofinsectsisnecessaryforthefullfertilityofthisplant。Analogousfactscouldbegivenwithrespecttothecrossingofmanyotherflowers，suchascarnations，etc。，ofwhichthevarietiesfluctuatemuchincolour。
Aswithflowers，sowithourdomesticatedanimals，nocharacterismorevariablethancolour，andprobablyinnoanimalmoresothanwiththehorse。Yet，withalittlecareinbreeding，itappearsthatracesofanycolourmightsoonbeformed。Hofackergivestheresultofmatchingtwohundredandsixteenmaresoffourdifferentcolourswithlike—colouredstallions，withoutregardtothecolouroftheirancestors;andofthetwohundredandsixteencoltsborn，elevenalonefailedtoinheritthecolouroftheirparents:AutenriethandAmmonassertthat，aftertwogenerations，coltsofauniformcolourareproducedwithcertainty。（12/50。Hofacker’UeberdieEigenschaften’etc。s。10。）]
Inafewrarecasespeculiaritiesfailtobeinherited，apparentlyfromtheforceofinheritancebeingtoostrong。Ihavebeenassuredbybreedersofthecanary—birdthattogetagoodjonquil—colouredbirditdoesnotanswertopairtwojonquils，asthecolourthencomesouttoostrong，orisevenbrown;butthisstatementisdisputedbyotherbreeders。Soagain，iftwocrestedcanariesarepaired，theyoungbirdsrarelyinheritthischaracter（12/51。Bechstein’Naturgesch。Deutschlands’b。4s。462。Mr。Brent，agreatbreederofcanaries，informsmethathebelievesthatthesestatementsarecorrect。）:forincrestedbirdsanarrowspaceofbareskinisleftonthebackofthehead，wherethefeathersareup—turnedtoformthecrest，and，whenbothparentsarethuscharacterised，thebarenessbecomesexcessive，andthecrestitselffailstobedeveloped。Mr。Hewitt，speakingofLacedSebrightBantams，says（12/52。’ThePoultryBook’byW。B。
Tegetmeier1866page245。）that，\"whythisshouldbesoIknownot，butI
amconfidentthatthosethatarebestlacedfrequentlyproduceoffspringveryfarfromperfectintheirmarkings，whilstthoseexhibitedbymyself，whichhavesooftenprovedsuccessful，werebredfromtheunionofheavily—
lacedbirdswiththosethatwerescarcelysufficientlylaced。\"
Itisasingularfactthat，althoughseveraldeaf—mutesoftenoccurinthesamefamily，andthoughtheircousinsandotherrelationsareofteninthesamecondition，yettheirparentsarerarelydeaf—mutes。Togiveasingleinstance:notonescholaroutof148，whowereatthesametimeintheLondonInstitution，wasthechildofparentssimilarlyaffected。Soagain，whenamaleorfemaledeaf—mutemarriesasoundperson，theirchildrenaremostrarelyaffected:inIreland，outof203childrenthusproducedonealonewasmute。Evenwhenbothparentshavebeendeaf—mutes，asinthecaseofforty—onemarriagesintheUnitedStatesandofsixinIreland，onlytwodeafanddumbchildrenwereproduced。Mr。Sedgwick（12/53。’BritishandForeignMed。—Chirurg。Review’July1861pages200—204。Mr。Sedgwickhasgivensuchfulldetailsonthissubject，withamplereferences，thatIneedrefertonootherauthorities），incommentingonthisremarkableandfortunatefailureinthepoweroftransmissioninthedirectline，remarksthatitmaypossiblybeowingto\"excesshavingreversedtheactionofsomenaturallawindevelopment。\"Butitissaferinthepresentstateofourknowledgetolookatthewholecaseassimplyunintelligible。
Althoughmanycongenitalmonstrositiesareinherited，ofwhichexampleshavealreadybeengiven，andtowhichmaybeaddedthelatelyrecordedcaseofthetransmissionduringacenturyofhare—lipwithacleft—palateinthewriter’sownfamily（12/54。Mr。Sproulein’BritishMedicalJournal’April18，1863。）yetothermalformationsarerarelyorneverinherited。Oftheselattercases，manyareprobablyduetoinjuriesinthewomboregg，andwouldcomeundertheheadofnon—inheritedinjuriesormutilations。Withplants，alongcatalogueofinheritedmonstrositiesofthemostseriousanddiversifiednaturecouldeasilybegiven;andwithplants，thereisnoreasontosupposethatmonstrositiesarecausedbydirectinjuriestotheseedorembryo。
Withrespecttotheinheritanceofstructuresmutilatedbyinjuriesoralteredbydisease，itwasuntillatelydifficulttocometoanydefiniteconclusion。Somemutilationshavebeenpractisedforavastnumberofgenerationswithoutanyinheritedresult。Godronremarks（12/55。’Del’Espece’tome21859page299。）thatdifferentracesofmanhavefromtimeimmemorialknockedouttheirupperincisors，cutoffjointsoftheirfingers，madeholesofimmensesizethroughthelobesoftheirearsorthroughtheirnostrils，tatooedthemselves，madedeepgashesinvariouspartsoftheirbodies，andthereisnoreasontosupposethatthesemutilationshaveeverbeeninherited。（12/56。NeverthelessMr。Wetherellstates，’Nature’December1870page168，thatwhenhevisitedfifteenyearsagotheSiouxIndians，hewasinformed\"byaphysician，whohaspassedmuchofhistimewiththesetribes，thatsometimesachildwasbornwiththesemarks。ThiswasconfirmedbytheU。S。GovernmentIndianAgent。\"）Adhesionsduetoinflammationandpitsfromthesmall—pox（andformerlymanyconsecutivegenerationsmusthavebeenthuspitted）arenotinherited。WithrespecttoJews，IhavebeenassuredbythreemedicalmenoftheJewishfaiththatcircumcision，whichhasbeenpractisedforsomanyages，hasproducednoinheritedeffect。Blumenbach，however，asserts（12/57。
’Philosoph。Mag。’volume41799page5。）thatJewsareoftenborninGermanyinaconditionrenderingcircumcisiondifficult，sothatanameisgiventhemsignifying\"borncircumcised;\"andProfessorPreyerinformsmethatthisisthecaseinBonn，suchchildrenbeingconsideredthespecialfavouritesofJehovah。IhavealsoheardfromDr。A。Newman，ofGuy’sHospital，ofthegrandsonofacircumcisedJew，thefathernothavingbeencircumcised，inasimilarcondition。Butitispossiblethatallthesecasesmaybeaccidentalcoincidence，forSirJ。Pagethasseenfivesonsofaladyandonesonofhersisterwithadherentprepuces;andoneoftheseboyswasaffectedinamanner\"whichmightbeconsideredlikethatcommonlyproducedbycircumcision;\"yettherewasnosuspicionofJewishbloodinthefamilyofthesetwosisters。CircumcisionispractisedbyMahomedans，butatamuchlateragethanbyJews;andDr。Riedel，AssistantResidentinNorthCelebes，writestomethattheboystheregonakeduntilfromsixtotenyearsold;andhehasobservedthatmanyofthem，thoughnotall，havetheirprepucesmuchreducedinlength，andthisheattributestotheinheritedeffectsoftheoperation。Inthevegetablekingdomoaksandothertreeshavebornegallsfromprimevaltimes，yettheydonotproduceinheritedexcrescences;andmanyothersuchfactscouldbeadduced。
Notwithstandingtheaboveseveralnegativecases，wenowpossessconclusiveevidencethattheeffectsofoperationsaresometimesinherited。Dr。Brown—
Sequard（12/58。’Proc。RoyalSoc。’volume10page297。’CommunicationtotheBrit。Assoc。’1870。’TheLancet’January1875page7。Theextractsarefromthislastpaper。ItappearsthatObersteiner’Stricker’sMed。
Jahrbucher’1875No。2hasconfirmedBrown—Sequard’sobservations。）givesthefollowingsummaryofhisobservationsonguinea—pigs;andthissummaryissoimportantthatIwillquotethewhole:——
[\"1st。Appearanceofepilepsyinanimalsbornofparentshavingbeenrenderedepilepticbyaninjurytothespinalcord。
\"2nd。Appearanceofepilepsyalsoinanimalsbornofparentshavingbeenrenderedepilepticbythesectionofthesciaticnerve。
\"3rd。Achangeintheshapeoftheearinanimalsbornofparentsinwhichsuchachangewastheeffectofadivisionofthecervicalsympatheticnerve。
\"4th。Partialclosureoftheeyelidsinanimalsbornofparentsinwhichthatstateoftheeyelidshadbeencausedeitherbythesectionofthecervicalsympatheticnerveortheremovalofthesuperiorcervicalganglion。
\"5th。Exophthalmiainanimalsbornofparentsinwhichaninjurytotherestiformbodyhadproducedthatprotrusionoftheeyeball。ThisinterestingfactIhavewitnessedagoodmanytimes，andIhaveseenthetransmissionofthemorbidstateoftheeyecontinuethroughfourgenerations。Intheseanimals，modifiedbyheredity，thetwoeyesgenerallyprotruded，althoughintheparentsusuallyonlyoneshowedexophthalmia，thelesionhavingbeenmadeinmostcasesonlyononeofthecorporarestiformia。
\"6th。Haematomaanddrygangreneoftheearsinanimalsbornofparentsinwhichtheseear—alterationshadbeencausedbyaninjurytotherestiformbodynearthenibofthecalamus。
\"7th。Absenceoftwotoesoutofthethreeofthehindleg，andsometimesofthethree，inanimalswhoseparentshadeatenuptheirhind—legtoeswhichhadbecomeanaestheticfromasectionofthesciaticnervealone，orofthatnerveandalsoofthecrural。Sometimes，insteadofcompleteabsenceofthetoes，onlyapartofoneortwoorthreewasmissingintheyoung，althoughintheparentnotonlythetoesbutthewholefootwasabsent（partlyeatenoff，partlydestroyedbyinflammation，ulceration，organgrene）。
\"8th。Appearanceofvariousmorbidstatesoftheskinandhairoftheneckandfaceinanimalsbornofparentshavinghadsimilaralterationsinthesameparts，aseffectsofaninjurytothesciaticnerve。\"]
ItshouldbeespeciallyobservedthatBrown—Sequardhasbredduringthirtyyearsmanythousandguinea—pigsfromanimalswhichhadnotbeenoperatedupon，andnotoneofthesemanifestedtheepileptictendency。Norhasheeverseenaguinea—pigbornwithouttoes，whichwasnottheoffspringofparentswhichhadgnawedofftheirowntoesowingtothesciaticnervehavingbeendivided。Ofthislatterfactthirteeninstanceswerecarefullyrecorded，andagreaternumberwereseen;yetBrown—Sequardspeaksofsuchcasesasoneoftherarerformsofinheritance。Itisastillmoreinterestingfact——
[\"Thatthesciaticnerveinthecongenitallytoelessanimalhasinheritedthepowerofpassingthroughallthedifferentmorbidstateswhichhaveoccurredinoneofitsparentsfromthetimeofthedivisiontillafteritsreunionwiththeperiphericend。Itisnotthereforesimplythepowerofperforminganactionwhichisinherited，butthepowerofperformingawholeseriesofactions，inacertainorder。\"]
InmostofthecasesofinheritancerecordedbyBrown—Sequardonlyoneofthetwoparentshadbeenoperateduponandwasaffected。Heconcludesbyexpressinghisbeliefthat\"whatistransmittedisthemorbidstateofthenervoussystem，\"duetotheoperationperformedontheparents。
WiththeloweranimalsDr。ProsperLucashascollectedalonglistofinheritedinjuries。Afewinstanceswillsuffice。Acowlostahornfromanaccidentwithconsequentsuppuration，andsheproducedthreecalveswhichwerehornlessonthesamesideofthehead。Withthehorse，thereseemshardlyadoubtthatexostosesonthelegs，causedbytoomuchtravellingonhardroads，areinherited。Blumenbachrecordsthecaseofamanwhohadhislittlefingerontherighthandalmostcutoff，andwhichinconsequencegrewcrooked，andhissonshadthesamefingeronthesamehandsimilarlycrooked。Asoldier，fifteenyearsbeforehismarriage，losthislefteyefrompurulentophthalmia，andhistwosonsweremicrophthalmiconthesameside。（12/59。ThislastcaseisquotedbyMr。Sedgwickin’BritishandForeignMedico—Chirurg。Review’April，1861page484。ForBlumenbachseeabove—citedpaper。SeealsoDr。P。Lucas’Traitedel’Hered。Nat。’tome2
page492。Also’Transact。Linn。Soc。’volume9page323。SomecuriouscasesaregivenbyMr。Bakerinthe’Veterinary’volume13page723。Anothercuriouscaseisgiveninthe’AnnalesdesScienc。Nat。’1stseries，tome11
page324。）Inallcasesinwhichaparenthashadanorganinjuredononeside，andtwoormoreoftheoffspringarebornwiththesameorganaffectedonthesameside，thechancesagainstmerecoincidencearealmostinfinitelygreat。Evenwhenonlyasinglechildisbornhavingexactlythesamepartofthebodyaffectedasthatofhisinjuredparent，thechancesagainstcoincidencearegreat;andProfessorRollestonhasgivenmetwosuchcaseswhichhavefallenunderhisownobservation，——namelyoftwomen，oneofwhomhadhiskneeandtheotherhischeekseverelycut，andbothhadchildrenbornwithexactlythesamespotmarkedorscarred。Manyinstanceshavebeenrecordedofcats，dogs，andhorses，whichhavehadtheirtails，legs，etc。，amputatedorinjured，producingoffspringwiththesamepartsill—formed;butasitisnotveryrareforsimilarmalformationstoappearspontaneously，allsuchcasesmaybeduetocoincidence。Itis，however，anargumentontheothersidethat\"undertheoldexciselawstheshepherd—dogwasonlyexemptfromtaxwhenwithoutatail，andforthisreasonitwasalwaysremoved\"（12/60。’TheDog’byStonehenge1867page118。）;andtherestillexistbreedsoftheshepherd—dogwhicharealwaysborndestituteofatail。Finally，itmustbeadmitted，moreespeciallysincethepublicationofBrown—Sequard’sobservations，thattheeffectsofinjuries，especiallywhenfollowedbydisease，orperhapsexclusivelywhenthusfollowed，areoccasionallyinherited。（12/61。TheMot—mothabituallybitesthebarbsoffthemiddlepartofthetwocentraltail—feathers，andasthebarbsarecongenitallysomewhatreducedonthesamepartofthesefeathers，itseemsextremelyprobable，asMr。Salvinremarks，’Proc。Zoolog。Soc。’1873page429，thatthisisduetotheinheritedeffectsoflong—continuedmutilation。）
CAUSESOFNON—INHERITANCE。
Alargenumberofcasesofnon—inheritanceareintelligibleontheprinciple，thatastrongtendencytoinheritancedoesexist，butthatitisoverbornebyhostileorunfavourableconditionsoflife。Noonewouldexpectthatourimprovedpigs，ifforcedduringseveralgenerationstotravelaboutandrootinthegroundfortheirownsubsistence，wouldtransmit，astrulyastheynowdotheirshortmuzzlesandlegs，andtheirtendencytofatten。Dray—horsesassuredlywouldnotlongtransmittheirgreatsizeandmassivelimbs，ifcompelledtoliveonacold，dampmountainousregion;wehaveindeedevidenceofsuchdeteriorationinthehorseswhichhaverunwildontheFalklandIslands。EuropeandogsinIndiaoftenfailtotransmittheirtruecharacter。Oursheepintropicalcountrieslosetheirwoolinafewgenerations。Thereseemsalsotobeacloserelationbetweencertainpeculiarpasturesandtheinheritanceofanenlargedtailinfat—tailedsheep，whichformoneofthemostancientbreedsintheworld。Withplants，wehaveseenthattropicalvarietiesofmaizelosetheirpropercharacterinthecourseoftwoorthreegenerations，whencultivatedinEurope;andconverselysoitiswithEuropeanvarietiescultivatedinBrazil。Ourcabbages，whichherecomesotruebyseed，cannotformheadsinhotcountries。AccordingtoCarriere（12/62。’ProductionetFixationdesVarietes’1865page72。）thepurple—
leafedbeechandbarberrytransmittheircharacterbyseedfarlesstrulyincertaindistrictsthaninothers。Underchangedcircumstances，periodicalhabitsoflifesoonfailtobetransmitted，astheperiodofmaturityinsummerandwinterwheat，barley，andvetches。Soitiswithanimals:forinstance，aperson，whosestatementIcantrust，procuredeggsofAylesburyducksfromthattown，wheretheyarekeptinhousesandarerearedasearlyaspossiblefortheLondonmarket;theducksbredfromtheseeggsinadistantpartofEngland，hatchedtheirfirstbroodonJanuary24th，whilstcommonducks，keptinthesameyardandtreatedinthesamemanner，didnothatchtilltheendofMarch;andthisshowsthattheperiodofhatchingwasinherited。ButthegrandchildrenoftheseAylesburyduckscompletelylosttheirhabitofearlyincubation，andhatchedtheireggsatthesametimewiththecommonducksofthesameplace。
Manycasesofnon—inheritanceapparentlyresultfromtheconditionsoflifecontinuallyinducingfreshvariability。Wehaveseenthatwhentheseedsofpears，plums，apples，etc。，aresown，theseedlingsgenerallyinheritsomedegreeoffamilylikeness。Mingledwiththeseseedlings，afew，andsometimesmany，worthless，wild—lookingplantscommonlyappear，andtheirappearancemaybeattributedtotheprincipleofreversion。Butscarcelyasingleseedlingwillbefoundperfectlytoresembletheparent—form;andthusmaybeaccountedforbyconstantlyrecurringvariabilityinducedbytheconditionsoflife。Ibelieveinthis，becauseithasbeenobservedthatcertainfruit—treestrulypropagatetheirkindwhilstgrowingontheirownroots;butwhengraftedonotherstocks，andbythisprocesstheirnaturalstateismanifestlyaffected，theyproduceseedlingswhichvarygreatly，departingfromtheparentaltypeinmanycharacters。（12/63。
Downing’FruitsofAmerica’page5:Sageret’Pom。Phys。’pages43，72。）
Metzger，asstatedintheninthchapter，foundthatcertainkindsofwheatbroughtfromSpainandcultivatedinGermany，failedduringmanyyearstoreproducethemselvestruly;butatlast，whenaccustomedtotheirnewconditions，theyceasedtobevariable，——thatis，theybecameamenabletothepowerofinheritance。Nearlyalltheplantswhichcannotbepropagatedwithanyapproachtocertaintybyseed，arekindswhichhavebeenlongpropagatedbybuds，cuttings，offsets，tubers，etc。，andhaveinconsequencebeenfrequentlyexposedduringwhatmaybecalledtheirindividuallivestowidelydiversifiedconditionsoflife。Plantsthuspropagatedbecomesovariable，thattheyaresubject，aswehaveseeninthelastchapter，eventobud—variation。Ourdomesticatedanimals，ontheotherhand，arenotcommonlyexposedduringthelifeoftheindividualtosuchextremelydiversifiedconditions，andarenotliabletosuchextremevariability;thereforetheydonotlosethepoweroftransmittingmostoftheircharacteristicfeatures。Intheforegoingremarksonnon—inheritance，crossedbreedsareofcourseexcluded，astheirdiversitymainlydependsontheunequaldevelopmentofcharacterderivedfromeitherparentortheirancestors。
CONCLUSION。
Ithasbeenshownintheearlypartofthischapterhowcommonlynewcharactersofthemostdiversifiednature，whethernormalorabnormal，injuriousorbeneficial，whetheraffectingorgansofthehighestormosttriflingimportance，areinherited。Itisoftensufficientfortheinheritanceofsomepeculiarcharacter，thatoneparentaloneshouldpossessit，asinmostcasesinwhichtherareranomalieshavebeentransmitted。Butthepoweroftransmissionisextremelyvariable。Inanumberofindividualsdescendedfromthesameparents，andtreatedinthesamemanner，somedisplaythispowerinaperfectmanner，andinsomeitisquitedeficient;andforthisdifferencenoreasoncanbeassigned。Theeffectsofinjuriesormutilationsareoccasionallyinherited;andweshallseeinafuturechapterthatthelong—continueduseanddisuseofpartsproducesaninheritedeffect。Eventhosecharacterswhichareconsideredthemostfluctuating，suchascolour，arewithrareexceptionstransmittedmuchmoreforciblythanisgenerallysupposed。Thewonder，indeed，inallcasesisnotthatanycharactershouldbetransmitted，butthatthepowerofinheritanceshouldeverfail。Thecheckstoinheritance，asfarasweknowthem，are，firstly，circumstanceshostiletotheparticularcharacterinquestion;secondly，conditionsoflifeincessantlyinducingfreshvariability;andlastly，thecrossingofdistinctvarietiesduringsomepreviousgeneration，togetherwithreversionoratavism—thatis，thetendencyinthechildtoresembleitsgrand—parentsormoreremoteancestorsinsteadofitsimmediateparents。Thislattersubjectwillbediscussedinthefollowingchapter。
ENDOFVOLUMEI。
TheVariationofAnimalsandPlantsunderDomesticationVolumeII
byCharlesDarwinINTWOVOLUMES
VOLUMEII。
CONTENTS。
CHAPTER2。XIII。——INHERITANCEcontinued——REVERSIONORATAVISM。
DIFFERENTFORMSOFREVERSION——INPUREORUNCROSSEDBREEDS，ASINPIGEONS，FOWLS，HORNLESSCATTLEANDSHEEP，INCULTIVATEDPLANTS——REVERSIONINFERAL
ANIMALSANDPLANTS——REVERSIONINCROSSEDVARIETIESANDSPECIES——REVERSION
THROUGHBUD—PROPAGATION，ANDBYSEGMENTSINTHESAMEFLOWERORFRUIT——IN
DIFFERENTPARTSOFTHEBODYINTHESAMEANIMAL——THEACTOFCROSSINGADIRECT
CAUSEOFREVERSION，VARIOUSCASESOF，WITHINSTINCTS——OTHERPROXIMATECAUSES
OFREVERSION——LATENTCHARACTERS——SECONDARYSEXUALCHARACTERS——UNEQUAL
DEVELOPMENTOFTHETWOSIDESOFTHEBODY——APPEARANCEWITHADVANCINGAGEOF
CHARACTERSDERIVEDFROMACROSS——THEGERM，WITHALLITSLATENTCHARACTERS，A
WONDERFULOBJECT——MONSTROSITIES——PELORICFLOWERSDUEINSOMECASESTO
REVERSION。
CHAPTER2。XIV。——INHERITANCEcontinued。——FIXEDNESSOFCHARACTER——PREPOTENCY——
SEXUALLIMITATION——CORRESPONDENCEOFAGE。
FIXEDNESSOFCHARACTERAPPARENTLYNOTDUETOANTIQUITYOFINHERITANCE——
PREPOTENCYOFTRANSMISSIONININDIVIDUALSOFTHESAMEFAMILY，INCROSSED
BREEDSANDSPECIES;OFTENSTRONGERINONESEXTHANTHEOTHER;SOMETIMESDUETO
THESAMECHARACTERBEINGPRESENTANDVISIBLEINONEBREEDANDLATENTINTHE
OTHER——INHERITANCEASLIMITEDBYSEX——NEWLY—ACQUIREDCHARACTERSINOUR
DOMESTICATEDANIMALSOFTENTRANSMITTEDBYONESEXALONE，SOMETIMESLOSTBYONE
SEXALONE——INHERITANCEATCORRESPONDINGPERIODSOFLIFE——THEIMPORTANCEOFTHE
PRINCIPLEWITHRESPECTTOEMBRYOLOGY;ASEXHIBITEDINDOMESTICATEDANIMALS:AS
EXHIBITEDINTHEAPPEARANCEANDDISAPPEARANCEOFINHERITEDDISEASES;SOMETIMES
SUPERVENINGEARLIERINTHECHILDTHANINTHEPARENT——SUMMARYOFTHETHREE
PRECEDINGCHAPTERS。
CHAPTER2。XV。——ONCROSSING。
FREEINTERCROSSINGOBLITERATESTHEDIFFERENCESBETWEENALLIEDBREEDS——WHENTHE
NUMBERSOFTWOCOMMINGLINGBREEDSAREUNEQUAL，ONEABSORBSTHEOTHER——THERATE
OFABSORPTIONDETERMINEDBYPREPOTENCYOFTRANSMISSION，BYTHECONDITIONSOF
LIFE，ANDBYNATURALSELECTION——ALLORGANICBEINGSOCCASIONALLYINTERCROSS;
APPARENTEXCEPTIONS——ONCERTAINCHARACTERSINCAPABLEOFFUSION;CHIEFLYOR
EXCLUSIVELYTHOSEWHICHHAVESUDDENLYAPPEAREDINTHEINDIVIDUAL——ONTHE
MODIFICATIONOFOLDRACES，ANDTHEFORMATIONOFNEWRACESBYCROSSING——SOME
CROSSEDRACESHAVEBREDTRUEFROMTHEIRFIRSTPRODUCTION——ONTHECROSSINGOF
DISTINCTSPECIESINRELATIONTOTHEFORMATIONOFDOMESTICRACES。
CHAPTER2。XVI。——CAUSESWHICHINTERFEREWITHTHEFREECROSSINGOFVARIETIES——
INFLUENCEOFDOMESTICATIONONFERTILITY。
DIFFICULTIESINJUDGINGOFTHEFERTILITYOFVARIETIESWHENCROSSED——VARIOUS
CAUSESWHICHKEEPVARIETIESDISTINCT，ASTHEPERIODOFBREEDINGANDSEXUAL
PREFERENCE——VARIETIESOFWHEATSAIDTOBESTERILEWHENCROSSED——VARIETIESOF
MAIZE，VERBASCUM，HOLLYHOCK，GOURDS，MELONS，ANDTOBACCO，RENDEREDINSOME
DEGREEMUTUALLYSTERILE——DOMESTICATIONELIMINATESTHETENDENCYTOSTERILITY
NATURALTOSPECIESWHENCROSSED——ONTHEINCREASEDFERTILITYOFUNCROSSED
ANIMALSANDPLANTSFROMDOMESTICATIONANDCULTIVATION。
CHAPTER2。XVII。——ONTHEGOODEFFECTSOFCROSSING，ANDONTHEEVILEFFECTSOF
CLOSEINTERBREEDING。
DEFINITIONOFCLOSEINTERBREEDING——AUGMENTATIONOFMORBIDTENDENCIES——GENERAL
EVIDENCEOFTHEGOODEFFECTSDERIVEDFROMCROSSING，ANDONTHEEVILEFFECTSOF
CLOSEINTERBREEDING——CATTLE，CLOSELYINTERBRED;HALF—WILDCATTLELONGKEPTIN
THESAMEPARKS——SHEEP——FALLOW—DEER——DOGS，RABBITS，PIGS——MAN，ORIGINOFHIS
ABHORRENCEOFINCESTUOUSMARRIAGES——FOWLS——PIGEONS——HIVE—BEES——PLANTS，GENERAL
CONSIDERATIONSONTHEBENEFITSDERIVEDFROMCROSSING——MELONS，FRUIT—TREES，PEAS，CABBAGES，WHEAT，ANDFOREST—TREES——ONTHEINCREASEDSIZEOFHYBRID
PLANTS，NOTEXCLUSIVELYDUETOTHEIRSTERILITY——ONCERTAINPLANTSWHICHEITHER
NORMALLYORABNORMALLYARESELF—IMPOTENT，BUTAREFERTILE，BOTHONTHEMALE
ANDFEMALESIDE，WHENCROSSEDWITHDISTINCTINDIVIDUALSEITHEROFTHESAMEOR
ANOTHERSPECIES——CONCLUSION。
CHAPTER2。XVIII。——ONTHEADVANTAGESANDDISADVANTAGESOFCHANGEDCONDITIONSOF
LIFE:STERILITYFROMVARIOUSCAUSES。
ONTHEGOODDERIVEDFROMSLIGHTCHANGESINTHECONDITIONSOFLIFE——STERILITY
FROMCHANGEDCONDITIONS，INANIMALS，INTHEIRNATIVECOUNTRYANDIN
MENAGERIES——MAMMALS，BIRDS，ANDINSECTs——LOSSOFSECONDARYSEXUALCHARACTERS
ANDOFINSTINCTS——CAUSESOFSTERILITY——STERILITYOFDOMESTICATEDANIMALSFROM
CHANGEDCONDITIONS——SEXUALINCOMPATIBILITYOFINDIVIDUALANIMALS——STERILITYOF
PLANTSFROMCHANGEDCONDITIONSOFLIFE——CONTABESCENCEOFTHEANTHERS——
MONSTROSITIESASACAUSEOFSTERILITY——DOUBLEFLOWERS——SEEDLESSFRUIT——
STERILITYFROMTHEEXCESSIVEDEVELOPMENTOFTHEORGANSOFVEGETATION——FROM
LONG—CONTINUEDPROPAGATIONBYBUDS——INCIPIENTSTERILITYTHEPRIMARYCAUSEOF
DOUBLEFLOWERSANDSEEDLESSFRUIT。
CHAPTER2。XIX。——SUMMARYOFTHEFOURLASTCHAPTERS，WITHREMARKSONHYBRIDISM。
ONTHEEFFECTSOFCROSSING——THEINFLUENCEOFDOMESTICATIONONFERTILITY——CLOSE
INTERBREEDING——GOODANDEVILRESULTSFROMCHANGEDCONDITIONSOFLIFE——
VARIETIESWHENCROSSEDNOTINVARIABLYFERTILE——ONTHEDIFFERENCEINFERTILITY
BETWEENCROSSEDSPECIESANDVARIETIES——CONCLUSIONSWITHRESPECTTOHYBRIDISM——
LIGHTTHROWNONHYBRIDISMBYTHEILLEGITIMATEPROGENYOFHETEROSTYLEDPLANTS——
STERILITYOFCROSSEDSPECIESDUETODIFFERENCESCONFINEDTOTHEREPRODUCTIVE
SYSTEM——NOTACCUMULATEDTHROUGHNATURALSELECTION——REASONSWHYDOMESTIC
VARIETIESARENOTMUTUALLYSTERILE——TOOMUCHSTRESSHASBEENLAIDONTHE
DIFFERENCEINFERTILITYBETWEENCROSSEDSPECIESANDCROSSEDVARIETIES——
CONCLUSION。
CHAPTER2。XX。——SELECTIONBYMAN。
SELECTIONADIFFICULTART——METHODICAL，UNCONSCIOUS，ANDNATURALSELECTION——
RESULTSOFMETHODICALSELECTION——CARETAKENINSELECTION——SELECTIONWITH
PLANTS——SELECTIONCARRIEDONBYTHEANCIENTSANDBYSEMI—CIVILISEDPEOPLE——
UNIMPORTANTCHARACTERSOFTENATTENDEDTO——UNCONSCIOUSSELECTION——AS
CIRCUMSTANCESSLOWLYCHANGE，SOHAVEOURDOMESTICATEDANIMALSCHANGED
THROUGHTHEACTIONOFUNCONSCIOUSSELECTION——INFLUENCEOFDIFFERENTBREEDERS
ONTHESAMESUB—VARIETY——PLANTSASAFFECTEDBYUNCONSCIOUSSELECTION——EFFECTS
OFSELECTIONASSHOWNBYTHEGREATAMOUNTOFDIFFERENCEINTHEPARTSMOST
VALUEDBYMAN。
CHAPTER2。XXI。——SELECTION，continued。
NATURALSELECTIONASAFFECTINGDOMESTICPRODUCTIONS——CHARACTERSWHICHAPPEAR
OFTRIFLINGVALUEOFTENOFREALIMPORTANCE——CIRCUMSTANCESFAVOURABLETO
SELECTIONBYMAN——FACILITYINPREVENTINGCROSSES，ANDTHENATUREOFTHE
CONDITIONS——CLOSEATTENTIONANDPERSEVERANCEINDISPENSABLE——THEPRODUCTIONOF
ALARGENUMBEROFINDIVIDUALSESPECIALLYFAVOURABLE——WHENNOSELECTIONIS
APPLIED，DISTINCTRACESARENOTFORMED——HIGHLY—BREDANIMALSLIABLETO
DEGENERATION——TENDENCYINMANTOCARRYTHESELECTIONOFEACHCHARACTERTOAN
EXTREMEPOINT，LEADINGTODIVERGENCEOFCHARACTER，RARELYTOCONVERGENCE——
CHARACTERSCONTINUINGTOVARYINTHESAMEDIRECTIONINWHICHTHEYHAVE
ALREADYVARIED——DIVERGENCEOFCHARACTER，WITHTHEEXTINCTIONOFINTERMEDIATE
VARIETIES，LEADSTODISTINCTNESSINOURDOMESTICRACES——LIMITTOTHEPOWEROF
SELECTION——LAPSEOFTIMEIMPORTANT——MANNERINWHICHDOMESTICRACESHAVE
ORIGINATED——SUMMARY。
CHAPTER2。XXII。——CAUSESOFVARIABILITY。
VARIABILITYDOESNOTNECESSARILYACCOMPANYREPRODUCTION——CAUSESASSIGNEDBY
VARIOUSAUTHORS——INDIVIDUALDIFFERENCES——VARIABILITYOFEVERYKINDDUETO
CHANGEDCONDITIONSOFLIFE——ONTHENATUREOFSUCHCHANGES——CLIMATE，FOOD，EXCESSOFNUTRIMENT——SLIGHTCHANGESSUFFICIENT——EFFECTSOFGRAFTINGONTHE
VARIABILITYOFSEEDLING—TREES——DOMESTICPRODUCTIONSBECOMEHABITUATEDTO
CHANGEDCONDITIONS——ONTHEACCUMULATIVEACTIONOFCHANGEDCONDITIONS——CLOSE
INTERBREEDINGANDTHEIMAGINATIONOFTHEMOTHERSUPPOSEDTOCAUSEVARIABILITY
——CROSSINGASACAUSEOFTHEAPPEARANCEOFNEWCHARACTERS——VARIABILITYFROM
THECOMMINGLINGOFCHARACTERSANDFROMREVERSION——ONTHEMANNERANDPERIODOF
ACTIONOFTHECAUSESWHICHEITHERDIRECTLY，ORINDIRECTLYTHROUGHTHE
REPRODUCTIVESYSTEM，INDUCEVARIABILITY。
CHAPTER2。XXIII。——DIRECTANDDEFINITEACTIONOFTHEEXTERNALCONDITIONSOF
LIFE。
SLIGHTMODIFICATIONSINPLANTSFROMTHEDEFINITEACTIONOFCHANGEDCONDITIONS，INSIZE，COLOUR，CHEMICALPROPERTIES，ANDINTHESTATEOFTHETISSUES——LOCAL
DISEASES——CONSPICUOUSMODIFICATIONSFROMCHANGEDCLIMATEORFOOD，ETC。——
PLUMAGEOFBIRDSAFFECTEDBYPECULIARNUTRIMENT，ANDBYTHEINOCULATIONOF
POISON——LAND—SHELLS——MODIFICATIONSOFORGANICBEINGSINASTATEOFNATURE
THROUGHTHEDEFINITEACTIONOFEXTERNALCONDITIONS——COMPARISONOFAMERICANAND
EUROPEANTREES——GALLS——EFFECTSOFPARASITICFUNGI——CONSIDERATIONSOPPOSEDTO
THEBELIEFINTHEPOTENTINFLUENCEOFCHANGEDEXTERNALCONDITIONS——PARALLEL
SERIESOFVARIETIES——AMOUNTOFVARIATIONDOESNOTCORRESPONDWITHTHEDEGREE
OFCHANGEINTHECONDITIONS——BUD—VARIATION——MONSTROSITIESPRODUCEDBY
UNNATURALTREATMENT——SUMMARY。
CHAPTER2。XXIV。——LAWSOFVARIATION——USEANDDISUSE，ETC。
NISUSFORMATIVUS，ORTHECO—ORDINATINGPOWEROFTHEORGANISATION——ONTHE
EFFECTSOFTHEINCREASEDUSEANDDISUSEOFORGANS——CHANGEDHABITSOFLIFE——
ACCLIMATISATIONWITHANIMALSANDPLANTS——VARIOUSMETHODSBYWHICHTHISCANBE
EFFECTED——ARRESTSOFDEVELOPMENT——RUDIMENTARYORGANS。
CHAPTER2。XXV。——LAWSOFVARIATION，continued。——CORRELATEDVARIABILITY。
EXPLANATIONOFTERMCORRELATION——CONNECTEDWITHDEVELOPMENT——MODIFICATIONS
CORRELATEDWITHTHEINCREASEDORDECREASEDSIZEOFPARTS——CORRELATEDVARIATION
OFHOMOLOGOUSPARTS——FEATHEREDFEETINBIRDSASSUMINGTHESTRUCTUREOFTHE
WINGS——CORRELATIONBETWEENTHEHEADANDTHEEXTREMITIES——BETWEENTHESKINAND
DERMALAPPENDAGES——BETWEENTHEORGANSOFSIGHTANDHEARING——CORRELATED
MODIFICATIONSINTHEORGANSOFPLANTS——CORRELATEDMONSTROSITIES——CORRELATION
BETWEENTHESKULLANDEARS——SKULLANDCRESTOFFEATHERS——SKULLANDHORNS——
CORRELATIONOFGROWTHCOMPLICATEDBYTHEACCUMULATEDEFFECTSOFNATURAL
SELECTION——COLOURASCORRELATEDWITHCONSTITUTIONALPECULIARITIES。
CHAPTER2。XXVI。——LAWSOFVARIATION，continued。——SUMMARY。
THEFUSIONOFHOMOLOGOUSPARTS——THEVARIABILITYOFMULTIPLEANDHOMOLOGOUS
PARTS——COMPENSATIONOFGROWTH——MECHANICALPRESSURE——RELATIVEPOSITIONOF
FLOWERSWITHRESPECTTOTHEAXIS，ANDOFSEEDSINTHEOVARY，ASINDUCING
VARIATION——ANALOGOUSORPARALLELVARIETIES——SUMMARYOFTHETHREELAST
CHAPTERS。
CHAPTER2。XXVII。——PROVISIONALHYPOTHESISOFPANGENESIS。
PRELIMINARYREMARKS。
FIRSTPART:——THEFACTSTOBECONNECTEDUNDERASINGLEPOINTOFVIEW，NAMELY，THEVARIOUSKINDSOFREPRODUCTION——REGROWTHOFAMPUTATEDPARTS——GRAFT—HYBRIDS
——THEDIRECTACTIONOFTHEMALEELEMENTONTHEFEMALE——DEVELOPMENT——THE
FUNCTIONALINDEPENDENCEOFTHEUNITSOFTHEBODY——VARIABILITY——INHERITANCE——
REVERSION。
SECONDPART:——STATEMENTOFTHEHYPOTHESIS——HOWFARTHENECESSARYASSUMPTIONS
AREIMPROBABLE——EXPLANATIONBYAIDOFTHEHYPOTHESISOFTHESEVERALCLASSESOF
FACTSSPECIFIEDINTHEFIRSTPART——CONCLUSION。
CHAPTER2。XXVIII。——CONCLUDINGREMARKS。
DOMESTICATION——NATUREANDCAUSESOFVARIABILITY——SELECTION——DIVERGENCEAND
DISTINCTNESSOFCHARACTER——EXTINCTIONOFRACES——CIRCUMSTANCESFAVOURABLETO
SELECTIONBYMAN——ANTIQUITYOFCERTAINRACES——THEQUESTIONWHETHEREACH
PARTICULARVARIATIONHASBEENSPECIALLYPREORDAINED。
INDEX。
THEVARIATIONOFANIMALSANDPLANTSUNDERDOMESTICATION。
VOLUMEII。
CHAPTER2。XIII。
INHERITANCEcontinued——REVERSIONORATAVISM。
DIFFERENTFORMSOFREVERSION。
INPUREORUNCROSSEDBREEDS，ASINPIGEONS，FOWLS，HORNLESSCATTLEANDSHEEP，INCULTIVATEDPLANTS。
REVERSIONINFERALANIMALSANDPLANTS。
REVERSIONINCROSSEDVARIETIESANDSPECIES。
REVERSIONTHROUGHBUD—PROPAGATION，ANDBYSEGMENTSINTHESAMEFLOWEROR
FRUIT。
INDIFFERENTPARTSOFTHEBODYINTHESAMEANIMAL。
THEACTOFCROSSINGADIRECTCAUSEOFREVERSION，VARIOUSCASESOF，WITH
INSTINCTS。
OTHERPROXIMATECAUSESOFREVERSION。
LATENTCHARACTERS。
SECONDARYSEXUALCHARACTERS。
UNEQUALDEVELOPMENTOFTHETWOSIDESOFTHEBODY。
APPEARANCEWITHADVANCINGAGEOFCHARACTERSDERIVEDFROMACROSS。
THEGERM，WITHALLITSLATENTCHARACTERS，AWONDERFULOBJECT。
MONSTROSITIES。
PELORICFLOWERSDUEINSOMECASESTOREVERSION。
Thegreatprincipleofinheritancetobediscussedinthischapterhasbeenrecognisedbyagriculturistsandauthorsofvariousnations，asshownbythescientifictermATAVISM，derivedfromatavus，anancestor;bytheEnglishtermsofREVERSION，orTHROWING—BACK;bytheFrenchPAS—EN—ARRIERE;andbytheGermanRUCKSCHLAG，orRUCKSCHRITT。Whenthechildresembleseithergrandparentmorecloselythanitsimmediateparents，ourattentionisnotmucharrested，thoughintruththefactishighlyremarkable;butwhenthechildresemblessomeremoteancestororsomedistantmemberinacollateralline，——andinthelastcasewemustattributethistothedescentofallthemembersfromacommonprogenitor，——wefeelajustdegreeofastonishment。Whenoneparentalonedisplayssomenewly—acquiredandgenerallyinheritablecharacter，andtheoffspringdonotinheritit，thecausemaylieintheotherparenthavingthepowerofprepotenttransmission。Butwhenbothparentsaresimilarlycharacterised，andthechilddoesnot，whateverthecausemaybe，inheritthecharacterinquestion，butresemblesitsgrandparents，wehaveoneofthesimplestcasesofreversion。Wecontinuallyseeanotherandevenmoresimplecaseofatavism，thoughnotgenerallyincludedunderthishead，namely，whenthesonmorecloselyresembleshismaternalthanhispaternalgrand—sireinsomemaleattribute，asinanypeculiarityinthebeardofman，thehornsofthebull，thehacklesorcombofthecock，or，asincertaindiseasesnecessarilyconfinedtothemalesex;forasthemothercannotpossessorexhibitsuchmaleattributes，thechildmustinheritthem，throughherblood，fromhismaternalgrandsire。
Thecasesofreversionmaybedividedintotwomainclasseswhich，however，insomeinstances，blendintooneanother;namely，first，thoseoccurringinavarietyorracewhichhasnotbeencrossed，buthaslostbyvariationsomecharacterthatitformerlypossessed，andwhichafterwardsreappears。Thesecondclassincludesallcasesinwhichanindividualwithsomedistinguishablecharacter，arace，orspecies，hasatsomeformerperiodbeencrossed，andacharacterderivedfromthiscross，afterhavingdisappearedduringoneorseveralgenerations，suddenlyreappears。Athirdclass，differingonlyinthemannerofreproduction，mightbeformedtoincludeallcasesofreversioneffectedbymeansofbuds，andthereforeindependentoftrueorseminalgeneration。Perhapsevenafourthclassmightbeinstituted，toincludereversionsbysegmentsinthesameindividualflowerorfruit，andindifferentpartsofthebodyinthesameindividualanimalasitgrowsold。
Butthetwofirstmainclasseswillbesufficientforourpurpose。
REVERSIONTOLOSTCHARACTERSBYPUREORUNCROSSEDFORMS。
Strikinginstancesofthisfirstclassofcasesweregiveninthesixthchapter，namely，oftheoccasionalreappearance，invariously—colouredbreedsofthepigeon，ofbluebirdswithallthemarkscharacteristicofthewildColumbalivia。Similarcasesweregiveninthecaseofthefowl。Withthecommonass，asthelegsofthewildprogenitorarealmostalwaysstriped，wemayfeelassuredthattheoccasionalappearanceofsuchstripesinthedomesticanimalisacaseofsimplereversion。ButIshallbecompelledtoreferagaintothesecases，andthereforeherepassthemover。
Theaboriginalspeciesfromwhichourdomesticatedcattleandsheeparedescended，nodoubtpossessedhorns;butseveralhornlessbreedsarenowwellestablished。Yetinthese——forinstance，inSouthdownsheep——\"itisnotunusualtofindamongthemalelambssomewithsmallhorns。\"Thehorns，whichthusoccasionallyreappearinotherpolledbreeds，either\"growtothefullsize，\"orarecuriouslyattachedtotheskinaloneandhang\"looselydown，ordropoff。\"（13/1。’YouattonSheep’pages20，234。ThesamefactofloosehornsoccasionallyappearinginhornlessbreedshasbeenobservedinGermany;
Bechstein’Naturgesch。Deutschlands。’b。1s。362。）TheGallowaysandSuffolkcattlehavebeenhornlessforthelast100or150years，butahornedcalf，withthehornoftenlooselyattached，isoccasionallyproduced。（13/2。’YouattonCattle’pages155，174。）
Thereisreasontobelievethatsheepintheirearlydomesticatedconditionwere\"brownordingyblack;\"buteveninthetimeofDavidcertainflockswerespokenofaswhiteassnow。DuringtheclassicalperiodthesheepofSpainaredescribedbyseveralancientauthorsasbeingblack，red，ortawny。（13/3。
’YouattonSheep’1838pages17，145。）Atthepresentday，notwithstandingthegreatcarewhichistakentopreventit，particolouredlambsandsomeentirelyblackareoccasionally，orevenfrequently，droppedbyourmosthighlyimprovedandvaluedbreeds，suchastheSouthdowns。SincethetimeofthefamousBakewell，duringthelastcentury，theLeicestersheephavebeenbredwiththemostscrupulouscare;yetoccasionallygrey—faced，orblack—spotted，orwhollyblacklambsappear。（13/4。IhavebeeninformedofthisfactthroughtheRev。W。D。FoxontheexcellentauthorityofMr。Wilmot:seealsoremarksonthissubjectinanarticleinthe’QuarterlyReview’1849page395。）Thisoccursstillmorefrequentlywiththelessimprovedbreeds，suchastheNorfolks。（13/5。Youattpages19，234。）Asbearingonthistendencyinsheeptoreverttodarkcolours，Imaystate（thoughindoingsoItrenchonthereversionofcrossedbreeds，andlikewiseonthesubjectofprepotency）thattheRev。W。D。FoxwasinformedthatsevenwhiteSouthdowneweswereputtoaso—calledSpanishram，whichhadtwosmallblackspotsonhissides，andtheyproducedthirteenlambs，allperfectlyblack。Mr。Foxbelievesthatthisrambelongedtoabreedwhichhehashimselfkept，andwhichisalwaysspottedwithblackandwhite;andhefindsthatLeicestersheepcrossedbyramsofthisbreedalwaysproduceblacklambs:hehasgoneonrecrossingthesecrossedsheepwithpurewhiteLeicestersduringthreesuccessivegenerations，butalwayswiththesameresult。Mr。Foxwasalsotoldbythefriendfromwhomthespottedbreedwasprocured，thathelikewisehadgoneonforsixorsevengenerationscrossingwithwhitesheep，butstillblacklambswereinvariablyproduced。
Similarfactscouldbegivenwithrespecttotaillessbreedsofvariousanimals。Forinstance，Mr。Hewitt（13/6。’ThePoultryBook’byMr。Tegetmeier1866page231。）statesthatchickensbredfromsomerumplessfowls，whichwerereckonedsogoodthattheywonaprizeatanexhibition，\"inaconsiderablenumberofinstanceswerefurnishedwithfullydevelopedtail—feathers。\"Oninquiry，theoriginalbreederofthesefowlsstatedthat，fromthetimewhenhehadfirstkeptthem，theyhadoftenproducedfowlsfurnishedwithtails;
butthattheselatterwouldagainreproducerumplesschickens。
Analogouscasesofreversionoccurinthevegetablekingdom;thus\"fromseedsgatheredfromthefinestcultivatedvarietiesofHeartsease（Violatricolor），plantsperfectlywildbothintheirfoliageandtheirflowersarefrequentlyproduced;\"（13/7。Loudon’s’Gardener’sMag。’volume101834page396:anurseryman，withmuchexperienceonthissubject，haslikewiseassuredmethatthissometimesoccurs。）butthereversioninthisinstanceisnottoaveryancientperiod，forthebestexistingvarietiesoftheheartseaseareofcomparativelymodernorigin。Withmostofourcultivatedvegetablesthereissometendencytoreversiontowhatisknowntobe，ormaybepresumedtobe，theiraboriginalstate;andthiswouldbemoreevidentifgardenersdidnotgenerallylookovertheirbedsofseedlings，andpullupthefalseplantsor\"rogues\"astheyarecalled。Ithasalreadybeenremarked，thatsomefewseedlingapplesandpearsgenerallyresemble，butapparentlyarenotidenticalwith，thewildtreesfromwhichtheyaredescended。Inourturnip（13/8。
’Gardener’sChronicle’1855page777。）andcarrot—bedsafewplantsoften\"break\"——thatis，flowertoosoon;andtheirrootsaregenerallyhardandstringy，asintheparent—species。Bytheaidofalittleselection，carriedonduringafewgenerations，mostofourcultivatedplantscouldprobablybebroughtback，withoutanygreatchangeintheirconditionsoflife，toawildornearlywildcondition:Mr。Buckmanhaseffectedthiswiththeparsnip（13/9。Ibid1862page721。）;andMr。HewettC。Watson，asheinformsme，selected，duringthreegenerations，\"themostdivergingplantsofScotchkail，perhapsoneoftheleastmodifiedvarietiesofthecabbage;andinthethirdgenerationsomeoftheplantscameveryclosetotheformsnowestablishedinEnglandaboutoldcastle—walls，andcalledindigenous。\"
REVERSIONINANIMALSANDPLANTSWHICHHAVERUNWILD。
Inthecaseshithertoconsidered，therevertinganimalsandplantshavenotbeenexposedtoanygreatorabruptchangeintheirconditionsoflifewhichcouldhaveinducedthistendency;butitisverydifferentwithanimalsandplantswhichhavebecomeferalorrunwild。Ithasbeenrepeatedlyassertedinthemostpositivemannerbyvariousauthors，thatferalanimalsandplantsinvariablyreturntotheirprimitivespecifictype。Itiscuriousonwhatlittleevidencethisbeliefrests。Manyofourdomesticatedanimalscouldnotsubsistinawildstate;thus，themorehighlyimprovedbreedsofthepigeonwillnot\"field\"orsearchfortheirownfood。Sheephaveneverbecomeferal，andwouldbedestroyedbyalmosteverybeastofprey。（13/10。Mr。Bonerspeaks（’Chamois—hunting’2ndedition1860page92）ofsheepoftenrunningwildintheBavarianAlps;but，onmakingfurtherinquiriesatmyrequest，hefoundthattheyarenotabletoestablishthemselves;theygenerallyperishfromthefrozensnowclingingtotheirwool，andtheyhavelosttheskillnecessarytopassoversteepicyslopes。Ononeoccasiontwoewessurvivedthewinter，buttheirlambsperished。）Inseveralcaseswedonotknowtheaboriginalparent—
species，andcannotpossiblytellwhetherornottherehasbeenanyclosedegreeofreversion。Itisnotknowninanyinstancewhatvarietywasfirstturnedout;severalvarietieshaveprobablyinsomecasesrunwild，andtheircrossingalonewouldtendtoobliteratetheirpropercharacter。Ourdomesticatedanimalsandplants，whentheyrunwild，mustalwaysbeexposedtonewconditionsoflife，for，asMr。Wallace（13/11。SeesomeexcellentremarksonthissubjectbyMr。Wallace’JournalProc。Linn。Soc。’1858volume3page60。）haswellremarked，theyhavetoobtaintheirownfood，andareexposedtocompetitionwiththenativeproductions。Underthesecircumstances，ifourdomesticatedanimalsdidnotundergochangeofsomekind，theresultwouldbequiteopposedtotheconclusionsarrivedatinthiswork。Nevertheless，Idonotdoubtthatthesimplefactofanimalsandplantsbecomingferal，doescausesometendencytoreversiontotheprimitivestate;thoughthistendencyhasbeenmuchexaggeratedbysomeauthors。
[Iwillbrieflyrunthroughtherecordedcases。Withneitherhorsesnorcattleistheprimitivestockknown;andithasbeenshowninformerchaptersthattheyhaveassumeddifferentcoloursindifferentcountries。ThusthehorseswhichhaverunwildinSouthAmericaaregenerallybrownish—bay，andintheEastdun—coloured;theirheadshavebecomelargerandcoarser，andthismaybeduetoreversion。Nocarefuldescriptionhasbeengivenoftheferalgoat。
Dogswhichhaverunwildinvariouscountrieshavehardlyanywhereassumedauniformcharacter;buttheyareprobablydescendedfromseveraldomesticraces，andaboriginallyfromseveraldistinctspecies。Feralcats，bothinEuropeandLaPlata，areregularlystriped;insomecasestheyhavegrowntoanunusuallylargesize，butdonotdifferfromthedomesticanimalinanyothercharacter。Whenvariously—colouredtamerabbitsareturnedoutinEurope，theygenerallyreacquirethecolouringofthewildanimal;therecanbenodoubtthatthisdoesreallyoccur，butweshouldrememberthatoddly—
colouredandconspicuousanimalswouldsuffermuchfrombeastsofpreyandfrombeingeasilyshot;thisatleastwastheopinionofagentlemanwhotriedtostockhiswoodswithanearlywhitevariety;ifthusdestroyed，theywouldbesupplantedby，insteadofbeingtransformedinto，thecommonrabbit。WehaveseenthattheferalrabbitsofJamaica，andespeciallyofPortoSanto，haveassumednewcoloursandothernewcharacters。Thebestknowncaseofreversion，andthatonwhichthewidelyspreadbeliefinitsuniversalityapparentlyrests，isthatofpigs。TheseanimalshaverunwildintheWestIndies，SouthAmerica，andtheFalklandIslands，andhaveeverywhereacquiredthedarkcolour，thethickbristles，andgreattusksofthewildboar;andtheyounghavereacquiredlongitudinalstripes。Buteveninthecaseofthepig，Roulindescribesthehalf—wildanimalsindifferentpartsofSouthAmericaasdifferinginseveralrespects。InLouisianathepig（13/12。DureaudelaMalle’ComptesRendus’tome411855page807。Fromthestatementsabovegiven，theauthorconcludesthatthewildpigsofLouisianaarenotdescendedfromtheEuropeanSusscrofa。）hasrunwild，andissaidtodifferalittleinform，andmuchincolour，fromthedomesticanimal，yetdoesnotcloselyresemblethewildboarofEurope。Withpigeonsandfowls（13/13。Capt。W。Allen，inhis’ExpeditiontotheNiger’statesthatfowlshaverunwildontheislandofAnnobon，andhavebecomemodifiedinformandvoice。Theaccountissomeagreandvaguethatitdidnotappeartomeworthcopying;butInowfindthatDureaudelaMalle（’ComptesRendus’tome411855page690）advancesthisasagoodinstanceofreversiontotheprimitivestock，andasconfirmatoryofastillmorevaguestatementinclassicaltimesbyVarro。），itisnotknownwhatvarietywasfirstturnedout，norwhatcharactertheferalbirdshaveassumed。