Theguinea—fowlintheWestIndies，whenferal，seemstovarymorethaninthedomesticatedstate。
　　Withrespecttoplantsrunwild，Dr。Hooker（13/14。’FloraofAustralia’1859
　　Introductionpage9。）hasstronglyinsistedonwhatslightevidencethecommonbeliefintheirreversiontoaprimitivestaterests。Godron（13/15。’Del’Espece’tome2pages54，58，60。）describeswildturnips，carrots，andcelery;buttheseplantsintheircultivatedstatehardlydifferfromtheirwildprototypes，exceptinthesucculencyandenlargementofcertainparts，——
　　characterswhichwouldcertainlybelostbyplantsgrowinginpoorsoilandstrugglingwithotherplants。Nocultivatedplanthasrunwildonsoenormousascaleasthecardoon（Cynaracardunculus）inLaPlata。Everybotanistwhohasseenitgrowingthere，invastbeds，ashighasahorse’sback，hasbeenstruckwithitspeculiarappearance;butwhetheritdiffersinanyimportantpointfromthecultivatedSpanishform，whichissaidnottobepricklylikeitsAmericandescendant，orwhetheritdiffersfromthewildMediterraneanspecies，whichissaidnottobesocial（thoughthismaybeduemerelytothenatureoftheconditions），Idonotknow。]
　　REVERSIONTOCHARACTERSDERIVEDFROMACROSS，INTHECASEOFSUB—VARIETIES，RACES，ANDSPECIES。
　　Whenanindividualhavingsomerecognisablepeculiarityuniteswithanotherofthesamesub—variety，nothavingthepeculiarityinquestion，itoftenreappearsinthedescendantsafteranintervalofseveralgenerations。Everyonemusthavenoticed，orheardfromoldpeopleofchildrencloselyresemblinginappearanceormentaldisposition，orinsosmallandcomplexacharacterasexpression，oneoftheirgrandparents，orsomemoredistantcollateralrelation。Verymanyanomaliesofstructureanddiseases（13/16。Mr。Sedgwickgivesmanyinstancesinthe’BritishandForeignMed。—Chirurg。Review’AprilandJuly1863pages448，188。）ofwhichinstanceshavebeengiveninthelastchapter，havecomeintoafamilyfromoneparent，andhavereappearedintheprogenyafterpassingovertwoorthreegenerations。Thefollowingcasehasbeencommunicatedtomeongoodauthority，andmay，Ibelieve，befullytrusted:apointer—bitchproducedsevenpuppies;fourweremarkedwithblueandwhite，whichissounusualacolourwithpointersthatshewasthoughttohaveplayedfalsewithoneofthegreyhounds，andthewholelitterwascondemned;butthegamekeeperwaspermittedtosaveoneasacuriosity。Twoyearsafterwardsafriendoftheownersawtheyoungdog，anddeclaredthathewastheimageofhisoldpointer—bitchSappho，theonlyblueandwhitepointerofpuredescentwhichhehadeverseen。Thisledtocloseinquiry，anditwasprovedthathewasthegreat—great—grandsonofSappho;sothat，accordingtothecommonexpression，hehadonly1/16thofherbloodinhisveins。Imaygiveoneotherinstance，ontheauthorityofMr。R。Walker，alargecattle—
　　breederinKincardineshire。Heboughtablackbull，thesonofablackcowwithwhitelegs，whitebellyandpartofthetailwhite;andin1870acalfthegr。—gr。—gr。—gr。—grandchildofthiscowwasborncolouredinthesameverypeculiarmanner;alltheintermediateoffspringhavingbeenblack。Inthesecasestherecanhardlybeadoubtthatacharacterderivedfromacrosswithanindividualofthesamevarietyreappearedafterpassingoverthreegenerationsintheonecase，andfiveintheother。
　　Whentwodistinctracesarecrossed，itisnotoriousthatthetendencyintheoffspringtoreverttooneorbothparent—formsisstrong，andenduresformanygenerations。Ihavemyselfseentheclearestevidenceofthisincrossedpigeonsandwithvariousplants。Mr。Sidney（13/17。Inhiseditionof’YouattonthePig’1860page27。）statesthat，inalitterofEssexpigs，twoyoungonesappearedwhichweretheimageoftheBerkshireboarthathadbeenusedtwenty—eightyearsbeforeingivingsizeandconstitutiontothebreed。I
　　observedinthefarmyardatBetleyHallsomefowlsshowingastronglikenesstotheMalaybreed，andwastoldbyMr。TolletthathehadfortyyearsbeforecrossedhisbirdswithMalays;andthat，thoughhehadatfirstattemptedtogetridofthisstrain，hehadsubsequentlygivenuptheattemptindespair，astheMalaycharacterwouldreappear。
　　Thisstrongtendencyincrossedbreedstoreverthasgivenrisetoendlessdiscussionsinhowmanygenerationsafterasinglecross，eitherwithadistinctbreedormerelywithaninferioranimal，thebreedmaybeconsideredaspure，andfreefromalldangerofreversion。Noonesupposesthatlessthanthreegenerationssuffices，andmostbreedersthinkthatsix，seven，oreightarenecessary，andsomegotostillgreaterlengths。（13/18。Dr。P。Lucas，’Hered。Nat。’tome2pages314，892:seeagoodpracticalarticleonthesubjectin’Gardener’sChronicle’1856page620。Icouldaddavastnumberofreferences，buttheywouldbesuperfluous。）Butneitherinthecaseofabreedwhichhasbeencontaminatedbyasinglecross，norwhen，intheattempttoformanintermediatebreed，half—bredanimalshavebeenmatchedtogetherduringmanygenerations，cananyrulebelaiddownhowsoonthetendencytoreversionwillbeobliterated。Itdependsonthedifferenceinthestrengthorprepotencyoftransmissioninthetwoparent—forms，ontheiractualamountofdifference，andonthenatureoftheconditionsoflifetowhichthecrossedoffspringareexposed。Butwemustbecarefulnottoconfoundthesecasesofreversiontocharacterswhichweregainedbyacross，withthoseunderthefirstclass，inwhichcharactersoriginallycommontoBOTHparents，butlostatsomeformerperiod，reappear;forsuchcharactersmayrecurafteranalmostindefinitenumberofgenerations。
　　Thelawofreversionisaspowerfulwithhybrids，whentheyaresufficientlyfertiletobreedtogether，orwhentheyarerepeatedlycrossedwitheitherpureparent—form，asinthecaseofmongrels。Itisnotnecessarytogiveinstances。Withplantsalmosteveryonewhohasworkedonthissubject，fromthetimeofKolreutertothepresentday，hasinsistedonthistendency。
　　Gartnerhasrecordedsomegoodinstances;butnoonehasgivenmorestrikingonesthanNaudin。（13/19。Kolreutergivescuriouscasesinhis’DritteFortsetzung’1766ss。53，59;andinhiswell—known’MemoirsonLavateraandJalapa。’Gartner’Bastarderzeugung’ss。437，441，etc。Naudininhis"Recherchessurl’Hybridite"’NouvellesArchivesduMuseum’tome1page25。）
　　Thetendencydiffersindegreeorstrengthindifferentgroups，andpartlydepends，asweshallpresentlysee，onwhethertheparent—plantshavebeenlongcultivated。Althoughthetendencytoreversionisextremelygeneralwithnearlyallmongrelsandhybrids，itcannotbeconsideredasinvariablycharacteristicofthem;itmayalsobemasteredbylong—continuedselection;
　　butthesesubjectswillmoreproperlybediscussedinafuturechapteronCrossing。Fromwhatweseeofthepowerandscopeofreversion，bothinpureraces，andwhenvarietiesorspeciesarecrossed，wemayinferthatcharactersofalmosteverykindarecapableofreappearingafterhavingbeenlostforagreatlengthoftime。Butitdoesnotfollowfromthisthatineachparticularcasecertaincharacterswillreappear;forinstance，thiswillnotoccurwhenaraceiscrossedwithanotherendowedwithprepotencyoftransmission。
　　Sometimesthepowerofreversionwhollyfails，withoutourbeingabletoassignanycauseforthefailure:thusithasbeenstatedthatinaFrenchfamilyinwhich85outofabove600members，duringsixgenerations，hadbeensubjecttonight—blindness，"therehasnotbeenasingleexampleofthisaffectioninthechildrenofparentswhowerethemselvesfreefromit。"
　　（13/20。QuotedbyMr。Sedgwickin’Med。—Chirurg。Review’April1861page485。
　　Dr。H。Dobellin’Med。—Chirurg。Transactions’volume46givesananalogouscaseinwhich，inalargefamily，fingerswiththickenedjointsweretransmittedtoseveralmembersduringfivegenerations;butwhentheblemishoncedisappeareditneverreappeared。）
　　REVERSIONTHROUGHBUD—PROPAGATION——PARTIALREVERSION，BYSEGMENTSINTHESAME
　　FLOWERORFRUIT，ORINDIFFERENTPARTSOFTHEBODYINTHESAMEINDIVIDUAL
　　ANIMAL。
　　Intheeleventhchaptermanycasesofreversionbybuds，independentlyofseminalgeneration，weregiven——aswhenaleaf—budonavariegated，acurled，orlaciniatedvarietysuddenlyreassumesitspropercharacter;oraswhenaProvence—roseappearsonamoss—rose，orapeachonanectarine—tree。Insomeofthesecasesonlyhalftheflowerorfruit，orasmallersegment，ormerestripes，reassumetheirformercharacter;andherewehavereversionbysegments。Vilmorin（13/21。Verlot’DesVarietes’1865page63。）hasalsorecordedseveralcaseswithplantsderivedfromseed，offlowersrevertingbystripesorblotchestotheirprimitivecolours:hestatesthatinallsuchcasesawhiteorpale—colouredvarietymustfirstbeformed，and，whenthisispropagatedforalengthoftimebyseed，stripedseedlingsoccasionallymaketheirappearance;andthesecanafterwardsbycarebemultipliedbyseed。
　　Thestripesandsegmentsjustreferredtoarenotdue，asfarasisknown，toreversiontocharactersderivedfromacross，buttocharacterslostbyvariation。Thesecases，however，asNaudin（13/22。’NouvellesArchivesduMuseum’tome1page25。Alex。Braun（inhis’Rejuvenescence’RaySoc。1853
　　page315）apparentlyholdsasimilaropinion。）insistsinhisdiscussionondisjunctionofcharacter，arecloselyanalogouswiththosegivenintheeleventhchapter，inwhichcrossedplantshavebeenknowntoproducehalf—and—
　　halforstripedflowersandfruit，ordistinctkindsofflowersonthesamerootresemblingthetwoparent—forms。Manypiebaldanimalsprobablycomeunderthissamehead。Suchcases，asweshallseeinthechapteronCrossing，apparentlyresultfromcertaincharactersnotreadilyblendingtogether，and，asaconsequenceofthisincapacityforfusion，theoffspringeitherperfectlyresembleoneoftheirtwoparents，orresembleoneparentinonepart，andtheotherparentinanotherpart;orwhilstyoungareintermediateincharacter，butwithadvancingagerevertwhollyorbysegmentstoeitherparent—form，ortoboth。Thus，youngtreesoftheCytisusadamiareintermediateinfoliageandflowersbetweenthetwoparent—forms;butwhenolderthebudscontinuallyreverteitherpartiallyorwhollytobothforms。ThecasesgivenintheeleventhchapteronthechangeswhichoccurredduringgrowthincrossedplantsofTropaeolum，Cereus，Datura，andLathyrusareallanalogous。As，however，theseplantsarehybridsofthefirstgeneration，andastheirbudsafteratimecometoresembletheirparentsandnottheirgrandparents，thesecasesdonotatfirstappeartocomeunderthelawofreversionintheordinarysenseoftheword;nevertheless，asthechangeiseffectedthroughasuccessionofbud—generationsonthesameplant，theymaybethusincluded。
　　Analogousfactshavebeenobservedintheanimalkingdom，andaremoreremarkable，astheyoccurinthesameindividualinthestrictestsense，andnotaswithplantsthroughasuccessionofbud—generations。Withanimalstheactofreversion，ifitcanbesodesignated，doesnotpassoveratruegeneration，butmerelyovertheearlystagesofgrowthinthesameindividual。
　　Forinstance，Icrossedseveralwhitehenswithablackcock，andmanyofthechickenswere，duringthefirstyear，perfectlywhite，butacquiredduringthesecondyearblackfeathers;ontheotherhand，someofthechickenswhichwereatfirstblack，becameduringthesecondyearpiebaldwithwhite。Agreatbreeder（13/23。Mr。Teebayin’ThePoultryBook’byMr。Tegetmeier1866page72。）says，thataPencilledBrahmahenwhichhasanyofthebloodoftheLightBrahmainher，will"occasionallyproduceapulletwellpencilledduringthefirstyear，butshewillmostlikelymoultbrownontheshouldersandbecomequiteunlikeheroriginalcoloursinthesecondyear。"ThesamethingoccurswithlightBrahmasifofimpureblood。Ihaveobservedexactlysimilarcaseswiththecrossedoffspringfromdifferentlycolouredpigeons。Buthereisamoreremarkablefact:Icrossedaturbit，whichhasafrillformedbythefeathersbeingreversedonitsbreast，withatrumpeter;andoneoftheyoungpigeonsthusraisedatfirstshowednotatraceofthefrill，but，aftermoultingthrice，asmallyetunmistakablydistinctfrillappearedonitsbreast。AccordingtoGirou（13/24。QuotedbyHofacker’UeberdieEigenschaften’etc。s。98。）calvesproducedfromaredcowbyablackbull，orfromablackcowbyaredbull，arenotrarelybornred，andsubsequentlybecomeblack。Ipossessadog，thedaughterofawhiteterrierbyafox—
　　colouredbulldog;asapuppyshewasquitewhite，butwhenaboutsixmonthsoldablackspotappearedonhernose，andbrownspotsonherears。Whenalittleoldershewasbadlywoundedontheback，andthehairwhichgrewonthecicatrixwasofabrowncolour，apparentlyderivedfromherfather。Thisisthemoreremarkable，aswithmostanimalshavingcolouredhair，thatwhichgrowsonawoundedsurfaceiswhite。
　　Intheforegoingcases，thecharacterswhichwithadvancingagereappeared，werepresentintheimmediatelyprecedinggenerations;butcharacterssometimesreappearinthesamemannerafteramuchlongerintervaloftime。
　　ThusthecalvesofahornlessraceofcattlewhichoriginatedinCorrientes，thoughatfirstquitehornless，astheybecomeadultsometimesacquiresmall，crooked，andloosehorns;andtheseinsucceedingyearsoccasionallybecomeattachedtotheskull。（13/25。Azara’EssaisHist。Nat。deParaguay’tome2
　　1801page372。）WhiteandblackBantams，bothofwhichgenerallybreedtrue，sometimesassumeastheygrowoldasaffronorredplumage。Forinstance，afirst—rateblackbantamhasbeendescribed，whichduringthreeseasonswasperfectlyblack，butthenannuallybecamemoreandmorered;anditdeservesnoticethatthistendencytochange，wheneveritoccursinabantam，"isalmostcertaintoprovehereditary。"（13/26。ThesefactsaregivenonthehighauthorityofMr。Hewittin’ThePoultryBook’byMr。Tegetmeier1866page248。）Thecuckooorblue—mottledDorkingcock，whenold，isliabletoacquireyellowororangehacklesinplaceofhisproperbluish—greyhackles。（13/27。
　　’ThePoultryBook’byTegetmeier1866page97。）NowasGallusbankivaiscolouredredandorange，andasDorkingfowlsandbantamsaredescendedfromthisspecies，wecanhardlydoubtthatthechangewhichoccasionallyoccursintheplumageofthesebirdsastheirageadvances，resultsfromatendencyintheindividualtoreverttotheprimitivetype。
　　CROSSINGASADIRECTCAUSEOFREVERSION。
　　Ithaslongbeennotoriousthathybridsandmongrelsoftenreverttobothortooneoftheirparent—forms，afteranintervaloffromtwotosevenoreight，or，accordingtosomeauthorities，evenagreaternumberofgenerations。Butthattheactofcrossinginitselfgivesanimpulsetowardsreversion，asshownbythereappearanceoflong—lostcharacters，hasnever，Ibelieve，beenhithertoproved。Theproofliesincertainpeculiarities，whichdonotcharacterisetheimmediateparents，andthereforecannothavebeenderivedfromthem，frequentlyappearingintheoffspringoftwobreedswhencrossed，whichpeculiaritiesneverappear，orappearwithextremerarity，inthesesamebreeds，aslongastheyareprecludedfromcrossing。Asthisconclusionseemstomehighlycuriousandnovel，Iwillgivetheevidenceindetail。
　　[Myattentionwasfirstcalledtothissubject，andIwasledtomakenumerousexperiments，byMM。BoitardandCorbiehavingstatedthat，whentheycrossedcertainbreedsofpigeons，birdscolouredlikethewildC。livia，orthecommondovecote——namely，slaty—blue，withdoubleblackwing—bars，sometimeschequeredwithblack，whiteloins，thetailbarredwithblack，withtheouterfeathersedgedwithwhite，——werealmostinvariablyproduced。ThebreedswhichIcrossed，andtheremarkableresultsattained，havebeenfullydescribedinthesixthchapter。Iselectedpigeonsbelongingtotrueandancientbreeds，whichhadnotatraceofblueoranyoftheabovespecifiedmarks;butwhencrossed，andtheirmongrelsrecrossed，youngbirdswereoftenproduced，moreorlessplainlycolouredslaty—blue，withsomeorallofthepropercharacteristicmarks。Imayrecalltothereader’smemoryonecase，namely，thatofapigeon，hardlydistinguishablefromthewildShetlandspecies，thegrandchildofared—spot，whitefantail，andtwoblackbarbs，fromanyofwhich，whenpurely—bred，theproductionofapigeoncolouredlikethewildC。
　　liviawouldhavebeenalmostaprodigy。
　　Iwasthusledtomaketheexperiments，recordedintheseventhchapter，onfowls。Iselectedlong—establishedpurebreeds，inwhichtherewasnotatraceofred，yetinseveralofthemongrelsfeathersofthiscolourappeared;andonemagnificentbird，theoffspringofablackSpanishcockandwhiteSilkhen，wascolouredalmostexactlylikethewildGallusbankiva。AllwhoknowanythingofthebreedingofpoultrywilladmitthattensofthousandsofpureSpanishandofpurewhiteSilkfowlsmighthavebeenrearedwithouttheappearanceofaredfeather。Thefact，givenontheauthorityofMr。
　　Tegetmeier，ofthefrequentappearance，inmongrelfowls，ofpencilledortransversely—barredfeathers，likethosecommontomanygallinaceousbirds，islikewiseapparentlyacaseofreversiontoacharacterformerlypossessedbysomeancientprogenitorofthefamily。Iowetothekindnessofthisexcellentobservertheopportunityofinspectingsomeneck—hacklesandtail—feathersfromahybridbetweenthecommonfowlandaverydistinctspecies，theGallusvarius;andthesefeathersaretransverselystripedinaconspicuousmannerwithdarkmetallicblueandgrey，acharacterwhichcouldnothavebeenderivedfromeitherimmediateparent。
　　IhavebeeninformedbyMr。B。P。Brent，thathecrossedawhiteAylesburydrakeandablackso—calledLabradorduck，bothofwhicharetruebreeds，andheobtainedayoungdrakecloselylikethemallard（A。boschas）。Ofthemusk—
　　duck（Cairinamoschata，Linn。）therearetwosub—breeds，namely，whiteandslate—coloured;andtheseIaminformedbreedtrue，ornearlytrue。ButtheRev。W。D。Foxtellsmethat，byputtingawhitedraketoaslate—colouredduck，blackbirds，piedwithwhite，likethewildmusk—duck，werealwaysproduced。IhearfromMr。Blyththathybridsfromthecanaryandgold—finchalmostalwayshavestreakedfeathersontheirbacks;andthisstreakingmustbederivedfromtheoriginalwildcanary。
　　Wehaveseeninthefourthchapter，thattheso—calledHimalayanrabbit，withitssnow—whitebody，blackears，nose，tail，andfeet，breedsperfectlytrue。
　　Thisraceisknowntohavebeenformedbytheunionoftwovarietiesofsilver—greyrabbits。Now，whenaHimalayandoewascrossedbyasandy—colouredbuck，asilver—greyrabbitwasproduced;andthisisevidentlyacaseofreversiontooneoftheparentvarieties。TheyoungoftheHimalayanrabbitarebornsnow—white，andthedarkmarksdonotappearuntilsometimesubsequently;butoccasionallyyoungHimalayanrabbitsarebornofalightsilver—grey，whichcoloursoondisappears;sothatherewehaveatraceofreversion，duringanearlyperiodoflife，totheparentvarieties，independentlyofanyrecentcross。
　　InthethirdchapteritwasshownthatatanancientperiodsomebreedsofcattleinthewilderpartsofBritainwerewhitewithdarkears，andthatthecattlenowkepthalfwildincertainparks，andthosewhichhaverunquitewildintwodistantpartsoftheworld，arelikewisethuscoloured。Now，anexperiencedbreeder，Mr。J。Beasley，ofNorthamptonshire（13/28。’Gardener’sChronicleandAgriculturalGazette’1866page528。），crossedsomecarefullyselectedWestHighlandcowswithpurely—bredshorthornbulls。Thebullswerered，redandwhite，ordarkroan;andtheHighlandcowswereallofaredcolour，incliningtoalightoryellowshade。Butaconsiderablenumberoftheoffspring——andMr。Beasleycallsattentiontothisasaremarkablefact——werewhite，orwhitewithredears。Bearinginmindthatnoneoftheparentswerewhite，andthattheywerepurely—bredanimals，itishighlyprobablethatheretheoffspringreverted，inconsequenceofthecross，tothecolourofsomeancientandhalf—wildparent—breed。Thefollowingcase，perhaps，comesunderthesamehead:cowsintheirnaturalstatehavetheiruddersbutlittledeveloped，anddonotyieldnearlysomuchmilkasourdomesticatedanimals。
　　Nowthereissomereasontobelieve（13/29。Ibid1860page343。IamgladtofindthatsoexperiencedabreederofcattleasMr。WilloughbyWood，’Gardener’sChronicle’1869page1216，admitsmyprincipleofacrossgivingatendencytoreversion。）thatcross—bredanimalsbetweentwokinds，bothofwhicharegoodmilkers，suchasAlderneysandShorthorns，oftenturnoutworthlessinthisrespect。
　　InthechapterontheHorsereasonswereassignedforbelievingthattheprimitivestockwasstripedanddun—coloured;anddetailsweregiven，showingthatinallpartsoftheworldstripesofadarkcolourfrequentlyappearalongthespine，acrossthelegs，andontheshoulders，wheretheyareoccasionallydoubleortreble，andevensometimesonthefaceandbodyofhorsesofallbreedsandofallcolours。Butthestripesappearmostfrequentlyonthevariouskindsofduns。Infoalstheyaresometimesplainlyseen，andsubsequentlydisappear。Thedun—colourandthestripesarestronglytransmittedwhenahorsethuscharacterisediscrossedwithanyother;butI
　　wasnotabletoprovethatstripeddunsaregenerallyproducedfromthecrossingoftwodistinctbreeds，neitherofwhichareduns，thoughthisdoessometimesoccur。
　　Thelegsoftheassareoftenstriped，andthismaybeconsideredasareversiontothewildparentform，theEquustaeniopusofAbyssinia（13/30。
　　Sclaterin’Proc。Zoolog。Soc。’1862page163。），whichisgenerallythusstriped。Inthedomesticanimalthestripesontheshoulderareoccasionallydouble，orforkedattheextremity，asincertainzebrinespecies。Thereisreasontobelievethatthefoalismorefrequentlystripedonthelegsthantheadultanimal。Aswiththehorse，Ihavenotacquiredanydistinctevidencethatthecrossingofdifferently—colouredvarietiesoftheassbringsoutthestripes。
　　Butnowletusturntotheresultofcrossingthehorseandass。AlthoughmulesarenotnearlysonumerousinEnglandasasses，Ihaveseenamuchgreaternumberwithstripedlegs，andwiththestripesfarmoreconspicuousthanineitherparent—form。Suchmulesaregenerallylight—coloured，andmightbecalledfallow—duns。Theshoulder—stripeinoneinstancewasdeeplyforkedattheextremity，andinanotherinstancewasdouble，thoughunitedinthemiddle。Mr。MartingivesafigureofaSpanishmulewithstrongzebra—likemarksonitslegs（13/31。’HistoryoftheHorse’page212。），andremarksthatmulesareparticularlyliabletobethusstripedontheirlegs。InSouthAmerica，accordingtoRoulin（13/32。’Mem。presentespardiversSavansal’Acad。Royale’tome61835page338。），suchstripesaremorefrequentandconspicuousinthemulethanintheass。IntheUnitedStates，Mr。Gosse（13/33。’LettersfromAlabama’1859page280。），speakingoftheseanimals，says，"thatinagreatnumber，perhapsinnineoutofeveryten，thelegsarebandedwithtransversedarkstripes。"
　　ManyyearsagoIsawintheZoologicalGardensacurioustriplehybrid，fromabaymare，byahybridfromamaleassandfemalezebra。Thisanimalwhenoldhadhardlyanystripes;butIwasassuredbythesuperintendent，thatwhenyoungithadshoulder—stripes，andfaintstripesonitsflanksandlegs。I
　　mentionthiscasemoreespeciallyasaninstanceofthestripesbeingmuchplainerduringyouththaninoldage。
　　Asthezebrahassuchaconspicuouslystripedbodyandlegs，itmighthavebeenexpectedthatthehybridsfromthisanimalandthecommonasswouldhavehadtheirlegsinsomedegreestriped;butitappearsfromthefiguresgiveninDr。Gray’s’KnowsleyGleanings’andstillmoreplainlyfromthatgivenbyGeoffroyandF。Cuvier（13/34。’Hist。Nat。desMammiferes’1820tome1），thatthelegsaremuchmoreconspicuouslystripedthantherestofthebody;andthisfactisintelligibleonlyonthebeliefthattheassaidsingiving，throughthepowerofreversion，thischaractertoitshybridoffspring。
　　Thequaggaisbandedoverthewholefrontpartofitsbodylikeazebra，buthasnostripesonitslegs，ormeretracesofthem。ButinthefamoushybridbredbyLordMorton（13/35。’Philosoph。Transact。’1821page20。）fromachestnut，nearlypurely—bred，Arabianmare，byamalequagga，thestripeswere"morestronglydefinedanddarkerthanthoseonthelegsof"thequagga。"ThemarewassubsequentlyputtoablackArabianhorse，andboretwocolts，bothofwhich，asformerlystated，wereplainlystripedonthelegs，andoneofthemlikewisehadstripesontheneckandbody。
　　TheEquusindicus（13/36。Sclaterin’Proc。Zoolog。Soc。’1862page163:thisspeciesistheGhor—KhurofN。W。India，andhasoftenbeencalledtheHemionusofPallas。SeealsoMr。Blyth’sexcellentpaperin’JournalofAsiaticSoc。ofBengal’volume281860page229。）ischaracterisedbyaspinalstripe，withoutshoulderorlegstripes;buttracesoftheselatterstripesmayoccasionallybeseenevenintheadult（13/37。Anotherspeciesofwildass，thetrueE。
　　hemionusorKiang，whichordinarilyhasnoshoulder—stripes，issaidoccasionallytohavethem;andthese，aswiththehorseandass，aresometimesdouble:seeMr。Blythinthepaperjustquotedandin’IndianSportingReview’
　　1856page320:andCol。HamiltonSmithin’Nat。Library，Horses’page318;and’Dict。Class。d’Hist。Nat。’tome3page563。）andColonelS。Poole，whohashadampleopportunitiesforobservation，informsmethatinthefoal，whenfirstborn，theheadandlegsareoftenstriped，buttheshoulder—stripeisnotsodistinctasinthedomesticass;allthesestripes，exceptingthatalongthespine，soondisappear。Nowahybrid，raisedatKnowsley（13/38。
　　Figuredinthe’GleaningsfromtheKnowsleyMenageries’byDr。J。E。Gray。）
　　fromafemaleofthisspeciesbyamaledomesticass，hadallfourlegstransverselyandconspicuouslystriped，hadthreeshortstripesoneachshoulderandhadevensomezebra—likestripesonitsface！Dr。Grayinformsmethathehasseenasecondhybridofthesameparentage，similarlystriped。
　　Fromthesefactsweseethatthecrossingoftheseveralequinespeciestendsinamarkedmannertocausestripestoappearonvariouspartsofthebody，especiallyonthelegs。Aswedonotknowwhethertheparent—formofthegenuswasstriped，theappearanceofthestripescanonlyhypotheticallybeattributedtoreversion。Butmostpersons，afterconsideringthemanyundoubtedcasesofvariouslycolouredmarksreappearingbyreversioninmyexperimentsoncrossedpigeonsandfowls，willcometothesameconclusionwithrespecttothehorse—genus;andifso，wemustadmitthattheprogenitorofthegroupwasstripedonthelegs，shoulders，face，andprobablyoverthewholebody，likeazebra。
　　Lastly，ProfessorJaegerhasgiven（13/39。’Darwin’scheTheorieundihreStellungzuMoralundReligion’page85。）agoodcasewithpigs。HecrossedtheJapaneseormaskedbreedwiththecommonGermanbreed，andtheoffspringwereintermediateincharacter。Hethenre—crossedoneofthesemongrelswiththepureJapanese，andinthelitterthusproducedoneoftheyoungresembledinallitscharactersawildpig;ithadalongsnoutanduprightears，andwasstripedontheback。ItshouldbeborneinmindthattheyoungoftheJapanesebreedarenotstriped，andthattheyhaveashortmuzzleandearsremarkablydependent。]
　　Asimilartendencytotherecoveryoflonglostcharactersholdsgoodevenwiththeinstinctsofcrossedanimals。Therearesomebreedsoffowlswhicharecalled"everlastinglayers，"becausetheyhavelosttheinstinctofincubation;andsorareisitforthemtoincubatethatIhaveseennoticespublishedinworksonpoultry，whenhensofsuchbreedshavetakentosit。
　　（13/40。CasesofbothSpanishandPolishhenssittingaregiveninthe’PoultryChronicle’1855volume3page477。）Yettheaboriginalspecieswasofcourseagoodincubator;andwithbirdsinastateofnaturehardlyanyinstinctissostrongasthis。Now，somanycaseshavebeenrecordedofthecrossedoffspringfromtworaces，neitherofwhichareincubators，becomingfirst—ratesitters，thatthereappearanceofthisinstinctmustbeattributedtoreversionfromcrossing。Oneauthorgoessofarastosay，"thatacrossbetweentwonon—sittingvarietiesalmostinvariablyproducesamongrelthatbecomesbroody，andsitswithremarkablesteadiness。"（13/41。’ThePoultryBook’byMr。Tegetmeier1866pages119，163。Theauthor，whoremarksonthetwonegatives（’Journ。ofHort。’1862page325），statesthattwobroodswereraisedfromaSpanishcockandSilver—pencilledHamburghhen，neitherofwhichareincubators，andnolessthansevenoutofeighthensinthesetwobroods"showedaperfectobstinacyinsitting。"TheRev。E。S。Dixon（’OrnamentalPoultry’1848page200）saysthatchickensrearedfromacrossbetweenGoldenandBlackPolishfowls，are"goodandsteadybirdstosit。"Mr。B。P。BrentinformsmethatheraisedsomegoodsittinghensbycrossingPencilledHamburghandPolishbreeds。Across—bredbirdfromaSpanishnon—incubatingcockandCochinincubatinghenismentionedinthe’PoultryChronicle’volume3page13，asan"exemplarymother。"Ontheotherhand，anexceptionalcaseisgiveninthe’CottageGardener’1860page388ofahenraisedfromaSpanishcockandblackPolishhenwhichdidnotincubate。）Anotherauthor，aftergivingastrikingexample，remarksthatthefactcanbeexplainedonlyontheprinciplethat"twonegativesmakeapositive。"Itcannot，however，bemaintainedthathensproducedfromacrossbetweentwonon—sittingbreedsinvariablyrecovertheirlostinstinct，anymorethanthatcrossedfowlsorpigeonsinvariablyrecovertheredorblueplumageoftheirprototypes。ThusI
　　raisedseveralchickensfromaPolishhenbyaSpanishcock，——breedswhichdonotincubate，——andnoneoftheyounghensatfirstshowedanytendencytosit;
　　butoneofthem——theonlyonewhichwaspreserved——inthethirdyearsatwellonhereggsandrearedabroodofchickens。Sothatherewehavethereappearancewithadvancingageofaprimitiveinstinct，inthesamemanneraswehaveseenthattheredplumageoftheGallusbankivaissometimesreacquiredbothbycrossedandpurely—bredfowlsofvariouskindsastheygrowold。
　　Theparentsofallourdomesticatedanimalswereofcourseaboriginallywildindisposition;andwhenadomesticatedspeciesiscrossedwithadistinctspecies，whetherthisisadomesticatedoronlyatamedanimal，thehybridsareoftenwildtosuchadegree，thatthefactisintelligibleonlyontheprinciplethatthecrosshascausedapartialreturntoaprimitivedisposition。Thus，theEarlofPowisformerlyimportedsomethoroughlydomesticatedhumpedcattlefromIndia，andcrossedthemwithEnglishbreeds，whichbelongtoadistinctspecies;andhisagentremarkedtome，withoutanyquestionhavingbeenasked，howoddlywildthecross—bredanimalswere。TheEuropeanwildboarandtheChinesedomesticatedpigarealmostcertainlyspecificallydistinct:SirF。DarwincrossedasowofthelatterbreedwithawildAlpineboarwhichhadbecomeextremelytame，buttheyoung，thoughhavinghalf—domesticatedbloodintheirveins，were"extremelywildinconfinement，andwouldnoteatswilllikecommonEnglishpigs。"CaptainHutton，inIndia，crossedatamegoatwithawildonefromtheHimalaya，andheremarkedtomehowsurprisinglywildtheoffspringwere。Mr。Hewitt，whohashadgreatexperienceincrossingtamecock—pheasantswithfowlsbelongingtofivebreeds，givesasthecharacterofall"extraordinarywildness"（13/42。’ThePoultryBook’byTegetmeier1866pages165，167。）;butIhavemyselfseenoneexceptiontothisrule。Mr。S。J。Salter（13/43。’NaturalHistoryReview’1863
　　Aprilpage277。）whoraisedalargenumberofhybridsfromabantam—henbyGallussonneratii，statesthat"allwereexceedinglywild。"Mr。Waterton（13/44。’EssaysonNaturalHistory’page917。）bredsomewildducksfromeggshatchedunderacommonduck，andtheyoungwereallowedtocrossfreelybothamongstthemselvesandwiththetameducks;theywere"halfwildandhalftame;theycametothewindowstobefed，butstilltheyhadawarinessaboutthemquiteremarkable。"
　　Ontheotherhand，mulesfromthehorseandassarecertainlynotintheleastwild，thoughnotoriousforobstinacyandvice。Mr。Brent，whohascrossedcanary—birdswithmanykindsoffinches，hasnotobserved，asheinformsme，thatthehybridswereinanywayremarkablywild:butMr。JennerWeirwhohashadstillgreaterexperience，isofadirectlyoppositeopinion。Heremarksthatthesiskinisthetamestoffinches，butitsmulesareaswild，whenyoung，asnewlycaughtbirds，andareoftenlostthroughtheircontinuedeffortstoescape。Hybridsareoftenraisedbetweenthecommonandmuskduck，andIhavebeenassuredbythreepersons，whohavekeptthesecrossedbirds，thattheywerenotwild;butMr。Garnett（13/45。AsstatedbyMr。Ortoninhis’PhysiologyofBreeding’page12。）observedthathishybridswerewild，andexhibited"migratorypropensities"ofwhichthereisnotavestigeinthecommonormuskduck。NocaseisknownofthislatterbirdhavingescapedandbecomewildinEuropeorAsia，except，accordingtoPallas，ontheCaspianSea;andthecommondomesticduckonlyoccasionallybecomeswildindistrictswherelargelakesandfensabound。Nevertheless，alargenumberofcaseshavebeenrecorded（13/46。M。E。deSelys—Longchampsrefers（’BulletinAcad。Roy。
　　deBruxelles’tome12No。10）tomorethansevenofthesehybridsshotinSwitzerlandandFrance。M。Debyasserts（’Zoologist’volume51845—46page1254）thatseveralhavebeenshotinvariouspartsofBelgiumandNorthernFrance。Audubon（’Ornitholog。Biography’volume3page168），speakingofthesehybrids，saysthat，inNorthAmerica，they"nowandthenwanderoffandbecomequitewild。"）ofhybridsfromthesetwoduckshavingbeenshotinacompletelywildstate，althoughsofewarerearedincomparisonwithpurely—bredbirdsofeitherspecies。Itisimprobablethatanyofthesehybridscouldhaveacquiredtheirwildnessfromthemusk—duckhavingpairedwithatrulywildduck;andthisisknownnottobethecaseinNorthAmerica;hencewemustinferthattheyhavereacquired，throughreversion，theirwildness，aswellasrenewedpowersofflight。
　　Theselatterfactsremindusofthestatements，sofrequentlymadebytravellersinallpartsoftheworld，onthedegradedstateandsavagedispositionofcrossedracesofman。Thatmanyexcellentandkind—heartedmulattoshaveexistednoonewilldispute;andamoremildandgentlesetofmencouldhardlybefoundthantheinhabitantsoftheislandofChiloe，whoconsistofIndianscommingledwithSpaniardsinvariousproportions。Ontheotherhand，manyyearsago，longbeforeIhadthoughtofthepresentsubject，Iwasstruckwiththefactthat，inSouthAmerica，menofcomplicateddescentbetweenNegroes，Indians，andSpaniards，seldomhad，whateverthecausemightbe，agoodexpression。（13/47。’JournalofResearches’1845page71。）
　　Livingstone——andamoreunimpeachableauthoritycannotbequoted，——afterspeakingofahalf—castemanontheZambesi，describedbythePortugueseasararemonsterofinhumanity，remarks，"Itisunaccountablewhyhalf—castes，suchashe，aresomuchmorecruelthanthePortuguese，butsuchisundoubtedlythecase。"AninhabitantremarkedtoLivingstone，"Godmadewhitemen，andGodmadeblackmen，buttheDevilmadehalfcastes。"（13/48。
　　’ExpeditiontotheZambesi’1865pages25，150。）Whentworaces，bothlowinthescale，arecrossedtheprogenyseemstobeeminentlybad。Thusthenoble—
　　heartedHumboldt，whofeltnoprejudiceagainsttheinferiorraces，speaksinstrongtermsofthebadandsavagedispositionofZambos，orhalf—castesbetweenIndiansandNegroes;andthisconclusionhasbeenarrivedatbyvariousobservers。（13/49。Dr。P。Brocaon’HybridityintheGenusHomo’
　　Englishtranslation1864page39。）Fromthesefactswemayperhapsinferthatthedegradedstateofsomanyhalf—castesisinpartduetoreversiontoaprimitiveandsavagecondition，inducedbytheactofcrossing，evenifmainlyduetotheunfavourablemoralconditionsunderwhichtheyaregenerallyreared。
　　SUMMARYONTHEPROXIMATECAUSESLEADINGTOREVERSION。
　　Whenpurely—bredanimalsorplantsreassumelong—lostcharacters，——whenthecommonass，forinstance，isbornwithstripedlegs，whenapureraceofblackorwhitepigeonsthrowsaslaty—bluebird，orwhenacultivatedheartseasewithlargeandroundedflowersproducesaseedlingwithsmallandelongatedflowers，——wearequiteunabletoassignanyproximatecause。Whenanimalsrunwild，thetendencytoreversion，which，thoughithasbeengreatlyexaggerated，nodoubtexists，issometimestoacertainextentintelligible。
　　Thus，withferalpigs，exposuretotheweatherwillprobablyfavourthegrowthofthebristles，asisknowntobethecasewiththehairofotherdomesticatedanimals，andthroughcorrelationthetuskswilltendtoberedeveloped。Butthereappearanceofcolouredlongitudinalstripesonyoungferalpigscannotbeattributedtothedirectactionofexternalconditions。
　　Inthiscase，andinmanyothers，wecanonlysaythatanychangeinthehabitsoflifeapparentlyfavouratendency，inherentorlatentinthespecies，toreturntotheprimitivestate。
　　Itwillbeshowninafuturechapterthatthepositionofflowersonthesummitoftheaxis，andthepositionofseedswithinthecapsule，sometimesdetermineatendencytowardsreversion;andthisapparentlydependsontheamountofsapornutrimentwhichtheflower—budsandseedsreceive。Theposition，also，ofbuds，eitheronbranchesoronroots，sometimesdetermines，aswasformerlyshown，thetransmissionofthecharacterpropertothevariety，oritsreversiontoaformerstate。
　　Wehaveseeninthelastsectionthatwhentworacesorspeciesarecrossedthereisthestrongesttendencytothereappearanceintheoffspringoflong—
　　lostcharacters，possessedbyneitherparentnorimmediateprogenitor。Whentwowhite，orred，orblackpigeons，ofwell—establishedbreeds，areunited，theoffspringarealmostsuretoinheritthesamecolours;butwhendifferently—colouredbirdsarecrossed，theopposedforcesofinheritanceapparentlycounteracteachother，andthetendencywhichisinherentinbothparentstoproduceslaty—blueoffspringbecomespredominant。Soitisinseveralothercases。Butwhen，forinstance，theassiscrossedwithE。
　　indicusorwiththehorse——animalswhichhavenotstripedlegs——andthehybridshaveconspicuousstripesontheirlegsandevenontheirfaces，allthatcanbesaidis，thataninherenttendencytoreversionisevolvedthroughsomedisturbanceintheorganisationcausedbytheactofcrossing。
　　Anotherformofreversionisfarcommoner，indeedisalmostuniversalwiththeoffspringfromacross，namely，tothecharacterspropertoeitherpureparent—form。Asageneralrule，crossedoffspringinthefirstgenerationarenearlyintermediatebetweentheirparents，butthegrandchildrenandsucceedinggenerationscontinuallyrevert，inagreaterorlesserdegree，tooneorbothoftheirprogenitors。Severalauthorshavemaintainedthathybridsandmongrelsincludeallthecharactersofbothparents，notfusedtogether，butmerelymingledindifferentproportionsindifferentpartsofthebody;
　　or，asNaudin（13/50。’NouvellesArchivesduMuseum’tome1page151。）hasexpressedit，ahybridisalivingmosaic—work，inwhichtheeyecannotdistinguishthediscordantelements，socompletelyaretheyintermingled。Wecanhardlydoubtthat，inacertainsense，thisistrue，aswhenwebeholdinahybridtheelementsofbothspeciessegregatingthemselvesintosegmentsinthesameflowerorfruit，byaprocessofself—attractionorself—affinity;
　　thissegregationtakingplaceeitherbyseminalorbud—propagation。Naudinfurtherbelievesthatthesegregationofthetwospecificelementsoressencesiseminentlyliabletooccurinthemaleandfemalereproductivematter;andhethusexplainsthealmostuniversaltendencytoreversioninsuccessivehybridgenerations。Forthiswouldbethenaturalresultoftheunionofpollenandovules，inbothofwhichtheelementsofthesamespecieshadbeensegregatedbyself—affinity。If，ontheotherhand，pollenwhichincludedtheelementsofonespecieshappenedtounitewithovulesincludingtheelementsoftheotherspecies，theintermediateorhybridstatewouldstillberetained，andtherewouldbenoreversion。Butitwould，asIsuspect，bemorecorrecttosaythattheelementsofbothparent—speciesexistineveryhybridinadoublestate，namely，blendedtogetherandcompletelyseparate。Howthisispossible，andwhatthetermspecificessenceorelementmaybesupposedtoexpress，Ishallattempttoshowinthechapteronthehypothesisofpangenesis。
　　ButNaudin’sview，aspropoundedbyhim，isnotapplicabletothereappearanceofcharacterslostlongagobyvariation;anditishardlyapplicabletoracesorspecieswhich，afterhavingbeencrossedatsomeformerperiodwithadistinctform，andhavingsincelostalltracesofthecross，neverthelessoccasionallyyieldanindividualwhichreverts（asinthecaseofthegreat—
　　great—grandchildofthepointerSappho）tothecrossingform。Themostsimplecaseofreversion，namely，ofahybridormongreltoitsgrandparents，isconnectedbyanalmostperfectserieswiththeextremecaseofapurely—bredracerecoveringcharacterswhichhadbeenlostduringmanyages;andwearethusledtoinferthatallthecasesmustberelatedbysomecommonbond。
　　Gartnerbelievedthatonlyhighlysterilehybridplantsexhibitanytendencytoreversiontotheirparent—forms。Thiserroneousbeliefmayperhapsbeaccountedforbythenatureofthegeneracrossedbyhim，forheadmitsthatthetendencydiffersindifferentgenera。ThestatementisalsodirectlycontradictedbyNaudin’sobservations，andbythenotoriousfactthatperfectlyfertilemongrelsexhibitthetendencyinahighdegree，——eveninahigherdegree，accordingtoGartnerhimself，thanhybrids。（13/51。
　　’Bastarderzeugung’s。582，438，etc。）
　　Gartnerfurtherstatesthatreversionsrarelyoccurwithhybridplantsraisedfromspecieswhichhavenotbeencultivated，whilst，withthosewhichhavebeenlongcultivated，theyareoffrequentoccurrence。Thisconclusionexplainsacuriousdiscrepancy:MaxWichura（13/52。’DieBastardbefruchtung……
　　derWeiden’1865s。23。ForGartner’sremarksonthishead，see’Bastarderzeugung’s。474，582。）whoworkedexclusivelyonwillowswhichhadnotbeensubjectedtoculture，neversawaninstanceofreversion;andhegoessofarastosuspectthatthecarefulGartnerhadnotsufficientlyprotectedhishybridsfromthepollenoftheparent—species:Naudin，ontheotherhand，whochieflyexperimentedoncucurbitaceousandothercultivatedplants，insistsmorestrenuouslythananyotherauthoronthetendencytoreversioninallhybrids。Theconclusionthattheconditionoftheparent—species，asaffectedbyculture，isoneoftheproximatecausesleadingtoreversion，agreeswellwiththeconversecaseofdomesticatedanimalsandcultivatedplantsbeingliabletoreversionwhentheybecomeferal;forinbothcasestheorganisationorconstitutionmustbedisturbed，thoughinaverydifferentway。（13/53。Prof。Weismanninhisverycuriousessayonthedifferentformsproducedbythesamespeciesofbutterflyatdifferentseasons（’Saison—
　　DimorphismusderSchmetterlinge’pages27，28），hascometoasimilarconclusion，namely，thatanycausewhichdisturbstheorganisation，suchastheexposureofthecocoonstoheatoreventomuchshaking，givesatendencytoreversion。）
　　Finally，wehaveseenthatcharactersoftenreappearinpurely—bredraceswithoutourbeingabletoassignanyproximatecause;butwhentheybecomeferalthisiseitherindirectlyordirectlyinducedbythechangeintheirconditionsoflife。Withcrossedbreeds，theactofcrossinginitselfcertainlyleadstotherecoveryoflong—lostcharacters，aswellasofthosederivedfromeitherparent—form。Changedconditions，consequentoncultivation，andtherelativepositionofbuds，flowers，andseedsontheplant，allapparentlyaidingivingthissametendency。Reversionmayoccureitherthroughseminalorbudgeneration，generallyatbirth，butsometimesonlywithanadvanceofage。Segmentsorportionsoftheindividualmayalonebethusaffected。Thatabeingshouldbebornresemblingincertaincharactersanancestorremovedbytwoorthree，andinsomecasesbyhundredsoreventhousandsofgenerations，isassuredlyawonderfulfact。Inthesecasesthechildiscommonlysaidtoinheritsuchcharactersdirectlyfromitsgrandparent，ormoreremoteancestors。Butthisviewishardlyconceivable。
　　If，however，wesupposethateverycharacterisderivedexclusivelyfromthefatherormother，butthatmanycharacterslielatentordormantinbothparentsduringalongsuccessionofgenerations，theforegoingfactsareintelligible。Inwhatmannercharactersmaybeconceivedtolielatent，willbeconsideredinafuturechaptertowhichIhavelatelyalluded。
　　LATENTCHARACTERS。
　　ButImustexplainwhatismeantbycharacterslyinglatent。Themostobviousillustrationisaffordedbysecondarysexualcharacters。Ineveryfemaleallthesecondarymalecharacters，andineverymaleallthesecondaryfemalecharacters，apparentlyexistinalatentstate，readytobeevolvedundercertainconditions。Itiswellknownthatalargenumberoffemalebirds，suchasfowls，variouspheasants，partridges，peahens，ducks，etc。，whenoldordiseased，orwhenoperatedon，assumemanyorallofthesecondarymalecharactersoftheirspecies。Inthecaseofthehen—pheasantthishasbeenobservedtooccurfarmorefrequentlyduringcertainyearsthanduringothers。
　　（13/54。Yarrell’Phil。Transact。’1827page268;Dr。Hamiltonin’Proc。
　　Zoolog。Soc。’1862page23。）Aducktenyearsoldhasbeenknowntoassumeboththeperfectwinterandsummerplumageofthedrake。（13/55。’Archiv。
　　Skand。BeitragezurNaturgesch。’8s。397—413。）Waterton（13/56。Inhis’EssaysonNat。Hist。’1838Mr。Hewittgivesanalogouscaseswithhen—
　　pheasantsin’JournalofHorticulture’July12，1864page37。IsidoreGeoffroySaint—Hilaireinhis’EssaisdeZoolog。Gen。’（’SuitesaBuffon’1842pages496—513），hascollectedsuchcasesintendifferentkindsofbirds。ItappearsthatAristotlewaswellawareofthechangeinmentaldispositioninoldhens。
　　Thecaseofthefemaledeeracquiringhornsisgivenatpage513。）givesacuriouscaseofahenwhichhadceasedlaying，andhadassumedtheplumage，voice，spurs，andwarlikedispositionofthecock;whenopposedtoanenemyshewoulderectherhacklesandshowfight。Thuseverycharacter，eventotheinstinctandmanneroffighting，musthavelaindormantinthishenaslongasherovariacontinuedtoact。Thefemalesoftwokindsofdeer，whenold，havebeenknowntoacquirehorns;and，asHunterhasremarked，weseesomethingofananalogousnatureinthehumanspecies。