Ifanimalsandplantshadneverbeendomesticated，andwildonesalonehadbeenobserved，weshouldprobablyneverhaveheardthesaying，that\"likebegetslike。\"Thepropositionwouldhavebeenasself—evidentasthatallthebudsonthesametreearealike，thoughneitherpropositionisstrictlytrue。For，ashasoftenbeenremarked，probablynotwoindividualsareidenticallythesame。Allwildanimalsrecogniseeachother，whichshowsthatthereissomedifferencebetweenthem;andwhentheeyeiswellpractised，theshepherdknowseachsheep，andmancandistinguishafellow—
manoutofmillionsonmillionsofothermen。Someauthorshavegonesofarastomaintainthattheproductionofslightdifferencesisasmuchanecessaryfunctionofthepowersofgeneration，astheproductionofoffspringliketheirparents。Thisview，asweshallseeinafuturechapter，isnottheoreticallyprobable，thoughpracticallyitholdsgood。
Thesayingthat\"likebegetslike\"has，infact，arisenfromtheperfectconfidencefeltbybreeders，thatasuperiororinferioranimalwillgenerallyreproduceitskind;butthisverysuperiorityorinferiorityshowsthattheindividualinquestionhasdepartedslightlyfromitstype。
Thewholesubjectofinheritanceiswonderful。Whenanewcharacterarises，whateveritsnaturemaybe，itgenerallytendstobeinherited，atleastinatemporaryandsometimesinamostpersistentmanner。Whatcanbemorewonderfulthanthatsometriflingpeculiarity，notprimordiallyattachedtothespecies，shouldbetransmittedthroughthemaleorfemalesexualcells，whicharesominuteasnottobevisibletothenakedeye，andafterwardsthroughtheincessantchangesofalongcourseofdevelopment，undergoneeitherinthewomborintheegg，andultimatelyappearintheoffspringwhenmature，orevenwhenquiteold，asinthecaseofcertaindiseases？Oragain，whatcanbemorewonderfulthanthewell—ascertainedfactthattheminuteovuleofagoodmilkingcowwillproduceamale，fromwhomacell，inunionwithanovule，willproduceafemale，andshe，whenmature，willhavelargemammaryglands，yieldinganabundantsupplyofmilk，andevenmilkofaparticularquality？Nevertheless，therealsubjectofsurpriseis，asSirH。Hollandhaswellremarked（12/1。’MedicalNotesandReflections’3rdedition1855page267。）notthatacharactershouldbeinherited，butthatanyshouldeverfailtobeinherited。Inafuturechapter，devotedtoanhypothesiswhichIhavetermedpangenesis，anattemptwillbemadetoshowthemeansbywhichcharactersofallkindsaretransmittedfromgenerationtogeneration。
Somewriters（12/2。Mr。Buckleinhis’HistoryofCivilisation’expressesdoubtsonthesubject，owingtothewantofstatistics。SeealsoMr。Bowen，ProfessorofMoralPhilosophy，in’Proc。AmericanAcad。ofSciences’volume5page102。），whohavenotattendedtonaturalhistory，haveattemptedtoshowthattheforceofinheritancehasbeenmuchexaggerated。Thebreedersofanimalswouldsmileatsuchsimplicity;andiftheycondescendedtomakeanyanswer，mightaskwhatwouldbethechanceofwinningaprizeiftwoinferioranimalswerepairedtogether？Theymightaskwhetherthehalf—wildArabswereledbytheoreticalnotionstokeeppedigreesoftheirhorses？
WhyhavepedigreesbeenscrupulouslykeptandpublishedoftheShorthorncattle，andmorerecentlyoftheHerefordbreed？Isitanillusionthattheserecentlyimprovedanimalssafelytransmittheirexcellentqualitiesevenwhencrossedwithotherbreeds？havetheShorthorns，withoutgoodreason，beenpurchasedatimmensepricesandexportedtoalmosteveryquarteroftheglobe，athousandguineashavingbeengivenforabull？Withgreyhoundspedigreeshavelikewisebeenkept，andthenamesofsuchdogs，asSnowball，Major，etc。，areaswellknowntocoursersasthoseofEclipseandHerodontheturf。EvenwiththeGamecock，pedigreesoffamousstrainswereformerlykept，andextendedbackforacentury。Withpigs，theYorkshireandCumberlandbreeders\"preserveandprintpedigrees;\"andtoshowhowsuchhighly—bredanimalsarevalued，ImaymentionthatMr。Brown，whowonallthefirstprizesforsmallbreedsatBirminghamin1850，soldayoungsowandboarofhisbreedtoLordDuciefor43guineas;thesowalonewasafterwardssoldtotheRev。F。Thursbyfor65guineas;whowrites，\"Shepaidmeverywell，havingsoldherproducefor300pounds，andhavingnowfourbreedingsowsfromher。\"（12/3。ForgreyhoundsseeLow’DomesticAnimalsoftheBritishIslands’1845page721。Forgame—fowlssee’ThePoultryBook’byMr。Tegetmeier1866page123。ForpigsseeMr。Sidney’seditionof’YouattonthePig’1860pages11，22。）Hardcashpaiddown，overandoveragain，isanexcellenttestofinheritedsuperiority。Infact，thewholeartofbreeding，fromwhichsuchgreatresultshavebeenattainedduringthepresentcentury，dependsontheinheritanceofeachsmalldetailofstructure。Butinheritanceisnotcertain;forifitwere，thebreeder’sart（12/4。’TheStudFarm’byCecilpage39。）wouldbereducedtoacertainty，andtherewouldbelittlescopeleftforthatwonderfulskillandperseveranceshownbythemenwhohaveleftanenduringmonumentoftheirsuccessinthepresentstateofourdomesticatedanimals。
Itishardlypossible，withinamoderatecompass，toimpressonthemindofthosewhohavenotattendedtothesubject，thefullconvictionoftheforceofinheritancewhichisslowlyacquiredbyrearinganimals，bystudyingthemanytreatiseswhichhavebeenpublishedonthevariousdomesticanimals，andbyconversingwithbreeders。Iwillselectafewfactsofthekind，which，asfarasIcanjudge，havemostinfluencedmyownmind。Withmanandthedomesticanimals，certainpeculiaritieshaveappearedinanindividual，atrareintervals，oronlyonceortwiceinthehistoryoftheworld，buthavereappearedinseveralofthechildrenandgrandchildren。ThusLambert，\"theporcupine—man，\"whoseskinwasthicklycoveredwithwartyprojections，whichwereperiodicallymoulted，hadallhissixchildrenandtwograndsonssimilarlyaffected。（12/5。
’PhilosophicalTransactions’1755page23。Ihaveseenonlysecond—handaccountsofthetwograndsons。Mr。Sedgwick，inapapertowhichIshallhereafteroftenrefer，statesthatFOURgenerationswereaffected，andineachthemalesalone。）Thefaceandbodybeingcoveredwithlonghair，accompaniedbydeficientteeth（towhichIshallhereafterrefer），occurredinthreesuccessivegenerationsinaSiamesefamily;butthiscaseisnotunique，asawoman（12/6。BarbaraVanBeck，figured，asIaminformedbytheRev。W。D。Fox，inWoodburn’s’GalleryofRarePortraits’1816volume2）
withacompletelyhairyfacewhowasexhibitedinLondonin1663，andanotherinstancehasrecentlyoccurred。ColonelHallam（12/7。’Proc。
Zoolog。Soc。’1833page16。）hasdescribedaraceoftwo—leggedpigs，\"thehinderextremitiesbeingentirelywanting;\"andthisdeficiencywastransmittedthroughthreegenerations。Infact，allracespresentinganyremarkablepeculiarity，suchassolid—hoofedswine，Mauchampsheep，niatacattle，etc。，areinstancesofthelong—continuedinheritanceofraredeviationsofstructure。
Whenwereflectthatcertainextraordinarypeculiaritieshavethusappearedinasingleindividualoutofmanymillions，allexposedinthesamecountrytothesamegeneralconditionsoflife，and，again，thatthesameextraordinarypeculiarityhassometimesappearedinindividualslivingunderwidelydifferentconditionsoflife，wearedriventoconcludethatsuchpeculiaritiesarenotdirectlyduetotheactionofthesurroundingconditions，buttounknownlawsactingontheorganisationorconstitutionoftheindividual;——thattheirproductionstandsinhardlycloserrelationtotheconditionsoflifethandoeslifeitself。Ifthisbeso，andtheoccurrenceofthesameunusualcharacterinthechildandparentcannotbeattributedtobothhavingbeenexposedtothesameunusualconditions，thenthefollowingproblemisworthconsideration，asshowingthattheresultcannotbedue，assomeauthorshavesupposed，tomerecoincidence，butmustbeconsequentonthemembersofthesamefamilyinheritingsomethingincommonintheirconstitution。Letitbeassumedthat，inalargepopulation，aparticularaffectionoccursonanaverageinoneoutofamillion，sothattheapriorichancethatanindividualtakenatrandomwillbesoaffectedisonlyoneinamillion。Letthepopulationconsistofsixtymillions，composed，wewillassume，oftenmillionfamilies，eachcontainingsixmembers。Onthesedata，ProfessorStokeshascalculatedformethattheoddswillbenolessthan8333millionsto1thatinthetenmillionfamiliestherewillnotbeevenasinglefamilyinwhichoneparentandtwochildrenwillbeaffectedbythepeculiarityinquestion。Butnumerousinstancescouldbegiven，inwhichseveralchildrenhavebeenaffectedbythesamerarepeculiaritywithoneoftheirparents;andinthiscase，moreespeciallyifthegrandchildrenbeincludedinthecalculation，theoddsagainstmerecoincidencebecomesomethingprodigious，almostbeyondenumeration。
Insomerespectstheevidenceofinheritanceismorestrikingwhenweconsiderthereappearanceoftriflingpeculiarities。Dr。HodgkinformerlytoldmeofanEnglishfamilyinwhich，formanygenerations，somemembershadasinglelockdifferentlycolouredfromtherestofthehair。IknewanIrishgentleman，who，ontherightsideofhishead，hadasmallwhitelockinthemidstofhisdarkhair:heassuredmethathisgrandmotherhadasimilarlockonthesameside，andhismotherontheoppositeside。Butitissuperfluoustogiveinstances;everyshadeofexpression，whichmayoftenbeseenalikeinparentsandchildren，tellsthesamestory。Onwhatacuriouscombinationofcorporealstructure，mentalcharacter，andtraining，handwritingdepends！yeteveryonemusthavenotedtheoccasionalclosesimilarityofthehandwritinginfatherandson，althoughthefatherhadnottaughthisson。Agreatcollectorofautographsassuredmethatinhiscollectiontherewereseveralsignaturesoffatherandsonhardlydistinguishableexceptbytheirdates。Hofacker，inGermany，remarksontheinheritanceofhandwriting;andithasevenbeenassertedthatEnglishboyswhentaughttowriteinFrancenaturallyclingtotheirEnglishmannerofwriting;butforsoextraordinaryastatementmoreevidenceisrequisite。
（12/8。Hofacker’UeberdieEigenschaften’etc。1828s。34。WithrespecttoFrance，ReportbyParisetin’ComptesRendus’1847page592。）Gait，gestures，voice，andgeneralbearingareallinherited，astheillustriousHunterandSirA。Carlislehaveinsisted。（12/9。HunterasquotedinHarlan’s’Med。Researches’page530。SirA。Carlisle’Phil。Transact。’1814
page94。）Myfathercommunicatedtomesomestrikinginstances，inoneofwhichamandiedduringtheearlyinfancyofhisson，andmyfather，whodidnotseethissonuntilgrownupandoutofhealth，declaredthatitseemedtohimasifhisoldfriendhadrisenfromthegrave，withallhishighlypeculiarhabitsandmanners。Peculiarmannerspassintotricks，andseveralinstancescouldbegivenoftheirinheritance;asinthecase，oftenquoted，ofthefatherwhogenerallysleptonhisback，withhisrightlegcrossedovertheleft，andwhosedaughter，whilstaninfantinthecradle，followedexactlythesamehabit，thoughanattemptwasmadetocureher。（12/10。GiroudeBuzareingues’DelaGeneration’page282。Ihavegivenananalogouscaseinmybookon’TheExpressionoftheEmotions。’）I
willgiveoneinstancewhichhasfallenundermyownobservation，andwhichiscuriousfrombeingatrickassociatedwithapeculiarstateofmind，namely，pleasureableemotion。Aboyhadthesingularhabit，whenpleased，ofrapidlymovinghisfingersparalleltoeachother，and，whenmuchexcited，ofraisingbothhands，withthefingersstillmoving，tothesidesofhisfaceonalevelwiththeeyes;whenthisboywasalmostanoldman，hecouldstillhardlyresistthistrickwhenmuchpleased，butfromitsabsurdityconcealedit。Hehadeightchildren。Ofthese，agirl，whenpleased，attheageoffourandahalfyears，movedherfingersinexactlythesameway，andwhatisstillodder，whenmuchexcited，sheraisedbothherhands，withherfingersstillmoving，tothesidesofherface，inexactlythesamemannerasherfatherhaddone，andsometimesevenstillcontinuedtodosowhenalone。Ineverheardofanyone，exceptingthisonemanandhislittledaughter，whohadthisstrangehabit;andcertainlyimitationwasinthisinstanceoutofthequestion。
Somewritershavedoubtedwhetherthosecomplexmentalattributes，onwhichgeniusandtalentdepend，areinherited，evenwhenbothparentsarethusendowed。ButhewhowillstudyMr。Galton’sableworkon’HereditaryGenius’willhaveitsdoubtsallayed。
Unfortunatelyitmattersnot，asfarasinheritanceisconcerned，howinjuriousaqualityorstructuremaybeifcompatiblewithlife。Noonecanreadthemanytreatises（12/11。TheworkswhichIhavereadandfoundmostusefulareDr。ProsperLucas’sgreatwork’Traitedel’HerediteNaturelle’
1847;Mr。W。Sedgwickin’BritishandForeignMedico—Chirurg。Review’AprilandJuly1861andAprilandJuly1863:Dr。GarrodonGoutisquotedinthesearticles。SirHenryHolland’MedicalNotesandReflections’3rdedition1855。Piorry’Del’HereditedanslesMaladies’1840。Adams’A
PhilosophicalTreatiseonHereditaryPeculiarities’2ndedition1815。Essayon’HereditaryDiseases’byDr。J。Steinan1843。SeePagetin’MedicalTimes’1857page192ontheInheritanceofCancer;Dr。Gouldin’Proc。ofAmericanAcad。ofSciences’November8，1853givesacuriouscaseofhereditarybleedinginfourgenerations。Harlan’MedicalResearches’page593。）onhereditarydiseaseanddoubtthis。Theancientswerestronglyofthisopinion，or，asRanchinexpressesit，OmnesGraeci，Arabes，etLatiniineoconsentiunt。Alongcataloguecouldbegivenofallsortsofinheritedmalformationsandofpredispositiontovariousdiseases。Withgout，fiftypercentofthecasesobservedinhospitalpracticeare，accordingtoDr。Garrod，inherited，andagreaterpercentageinprivatepractice。Everyoneknowshowofteninsanityrunsinfamilies，andsomeofthecasesgivenbyMr。Sedgwickareawful，——asofasurgeon，whosebrother，father，andfourpaternaluncleswereallinsane，thelatterdyingbysuicide;ofaJew，whosefather，mother，andsixbrothersandsisterswereallmad;andinsomeothercasesseveralmembersofthesamefamily，duringthreeorfoursuccessivegenerations，havecommittedsuicide。Strikinginstanceshavebeenrecordedofepilepsy，consumption，asthma，stoneinthebladder，cancer，profusebleedingfromtheslightestinjuries，ofthemothernotgivingmilk，andofbadparturitionbeinginherited。InthislatterrespectImaymentionanoddcasegivenbyagoodobserver（12/12。
MarshallquotedbyYouattinhisworkon’Cattle’page284。），inwhichthefaultlayintheoffspring，andnotinthemother:inapartofYorkshirethefarmerscontinuedtoselectcattlewithlargehind—quarters，untiltheymadeastraincalled\"Dutch—buttocked，\"and\"themonstroussizeofthebuttocksofthecalfwasfrequentlyfataltothecow，andnumbersofcowswereannuallylostincalving。\"
[Insteadofgivingnumerousdetailsonvariousinheritedmalformationsanddiseases，Iwillconfinemyselftooneorgan，thatwhichisthemostcomplex，delicate，andprobablybest—knowninthehumanframe，namely，theeye，withitsaccessoryparts。（12/13。Almostanyotherorganmighthavebeenselected。ForinstanceMr。J。Tomes’SystemofDentalSurgery’2ndedition1873page114givesmanyinstanceswithteeth，andothershavebeencommunicatedtome。）Tobeginwiththelatter:Ihavereceivedanaccountofafamilyinwhichoneparentandthechildrenareaffectedbydroopingeyelids，insopeculiaramanner，thattheycannotseewithoutthrowingtheirheadsbackwards。Mr。Wade，ofWakefield，hasgivenmeananalogouscaseofamanwhohadnothiseyelidsthusaffectedatbirth，norowedtheirstate，asfaraswasknown，toinheritance，buttheybegantodroopwhilsthewasaninfantaftersufferingfromfits，andhehastransmittedtheaffectiontotwooutofhisthreechildren，aswasevidentinthephotographsofthewholefamilysenttometogetherwiththisaccount。SirA。Carlisle（12/14。’Philosoph。Transact。’1814page94。）specifiesapendulousfoldtotheeyelids，asinherited。\"Inafamily，\"saysSirH。
Holland（12/15。’MedicalNotesandReflections’3rdeditionpage33。）
\"wherethefatherhadasingularelongationoftheuppereyelid，sevenoreightchildrenwerebornwiththesamedeformity;twoorthreeotherchildrenhavingitnot。\"Manypersons，asIhearfromSirJ。Paget，havetwoorthreehairsintheireyebrowsmuchlongerthantheothers;andevensotriflingapeculiarityasthiscertainlyrunsinfamilies。
Withrespecttotheeyeitself，thehighestauthorityinEngland，Mr。
Bowman，hasbeensokindastogivemethefollowingremarksoncertaininheritedimperfections。First，hypermetropia，ormorbidlylongsight:inthisaffection，theorgan，insteadofbeingspherical，istooflatfromfronttoback，andisoftenaltogethertoosmall，sothattheretinaisbroughttooforwardforthefocusofthehumours;consequentlyaconvexglassisrequiredforclearvisionofnearobjects，andfrequentlyevenofdistantones。Thisstateoccurscongenitally，orataveryearlyage，ofteninseveralchildrenofthesamefamily，whereoneoftheparentshaspresentedit。（12/16。Thisaffection，asIhearfromMr。Bowman，hasbeenablydescribedandspokenofashereditarybyDr。DondersofUtrecht，whoseworkwaspublishedinEnglishbytheSydenhamSocietyin1864。）Secondly，myopia，orshort—sight，inwhichtheeyeisegg—shapedandtoolongfromfronttoback;theretinainthiscaseliesbehindthefocus，andisthereforefittedtoseedistinctlyonlyverynearobjects。Thisconditionisnotcommonlycongenital，butcomesoninyouth，theliabilitytoitbeingwellknowntobetransmissiblefromparenttochild。Thechangefromthesphericaltotheovoidalshapeseemstheimmediateconsequenceofsomethinglikeinflammationofthecoats，underwhichtheyyield，andthereisgroundforbelievingthatitmayoftenoriginateincausesactingontheindividualaffected（12/17。M。Giraud—Teulonhasrecentlycollectedabundantstatisticalevidence，’RevuedesCoursScientifiques’September1870page625，showingthatshortsightisduetothehabitofviewingobjectsfromashortdistance，c’estletravailassidu，depres。）andmaythenceforwardbecometransmissible。WhenbothparentsaremyopicMr。Bowmanhasobservedthehereditarytendencyinthisdirectiontobeheightened，andsomeofthechildrentobemyopicatanearlierageorinahigherdegreethantheirparents。Thirdly，squintingisafamiliarexampleofhereditarytransmission:itisfrequentlyaresultofsuchopticaldefectsashavebeenabovementioned;butthemoreprimaryanduncomplicatedformsofitarealsosometimesinamarkeddegreetransmittedinafamily。
Fourthly，CATARACT，oropacityofthecrystallinelens，iscommonlyobservedinpersonswhoseparentshavebeensimilarlyaffected，andoftenatanearlierageinthechildrenthanintheparents。Occasionallymorethanonechildinafamilyisthusafflicted，oneofwhoseparentsorotherrelations，presentsthesenileformofthecomplaint。Whencataractaffectsseveralmembersofafamilyinthesamegeneration，itisoftenseentocommenceataboutthesameageineach:e。g。，inonefamilyseveralinfantsoryoungpersonsmaysufferfromit;inanother，severalpersonsofmiddleage。Mr。Bowmanalsoinformsmethathehasoccasionallyseen，inseveralmembersofthesamefamily，variousdefectsineithertherightorlefteye;andMr。WhiteCooperhasoftenseenpeculiaritiesofvisionconfinedtooneeyereappearinginthesameeyeintheoffspring。（12/18。QuotedbyMr。HerbertSpencer’PrinciplesofBiology’volume1page244。）
ThefollowingcasesaretakenfromanablepaperbyMr。W。Sedgwick，andfromDr。ProsperLucas。（12/19。’BritishandForeignMedico—Chirurg。
Review’April1861pages482—6;’L’Hered。Nat。’tome1pages391—408。）
Amaurosis，eithercongenitalorcomingonlateinlife，andcausingtotalblindness，isofteninherited;ithasbeenobservedinthreesuccessivegenerations。Congenitalabsenceoftheirishaslikewisebeentransmittedforthreegenerations，acleft—irisforfourgenerations，beinglimitedinthislattercasetothemalesofthefamily。Opacityofthecorneaandcongenitalsmallnessoftheeyeshavebeeninherited。Portalrecordsacuriouscase，inwhichafatherandtwosonswererenderedblind，whenevertheheadwasbentdownwards，apparentlyowingtothecrystallinelens，withitscapsule，slippingthroughanunusuallylargepupilintotheanteriorchamberoftheeye。Day—blindness，orimperfectvisionunderabrightlight，isinherited，asisnight—blindness，oranincapacitytoseeexceptunderastronglight:acasehasbeenrecorded，byM。Cunier，ofthislatterdefecthavingaffectedeighty—fivemembersofthesamefamilyduringsixgenerations。Thesingularincapacityofdistinguishingcolours，whichhasbeencalledDALTONISM，isnotoriouslyhereditary，andhasbeentracedthroughfivegenerations，inwhichitwasconfinedtothefemalesex。
Withrespecttothecolouroftheiris:deficiencyofcolouringmatteriswellknowntobehereditaryinalbinoes。Theirisofoneeyebeingofdifferentcolourfromthatoftheother，andtheirisbeingspotted，arecaseswhichhavebeeninherited。Mr。Sedgwickgives，inaddition，ontheauthorityofDr。Osborne（12/20。Dr。Osborne，Pres。ofRoyalCollegeofPhys。inIreland，publishedthiscaseinthe’DublinMedicalJournal’for1835。），thefollowingcuriousinstanceofstronginheritance:afamilyofsixteensonsandfivedaughtersallhadeyes\"resemblinginminiaturethemarkingsonthebackofatortoiseshellcat。\"Themotherofthislargefamilyhadthreesistersandabrotherallsimilarlymarked，andtheyderivedthispeculiarityfromtheirmother，whobelongedtoafamilynotoriousfortransmittingittotheirposterity。
Finally，Dr。Lucasemphaticallyremarksthatthereisnotonesinglefacultyoftheeyewhichisnotsubjecttoanomalies;andnotonewhichisnotsubjectedtotheprincipleofinheritance。Mr。Bowmanagreeswiththegeneraltruthofthisproposition;whichofcoursedoesnotimplythatallmalformationsarenecessarilyinherited;thiswouldnotevenfollowifbothparentswereaffectedbyananomalywhichinmostcaseswastransmissible。]
Evenifnosinglefacthadbeenknownwithrespecttotheinheritanceofdiseaseandmalformationsbyman，theevidencewouldhavebeenampleinthecaseofthehorse。Andthismighthavebeenexpected，ashorsesbreedmuchquickerthanman，arematchedwithcare，andarehighlyvalued。Ihaveconsultedmanyworks，andtheunanimityofthebeliefbyveterinariesofallnationsinthetransmissionofvariousmorbidtendenciesissurprising。
Authorswhohavehadwideexperiencegiveindetailmanysingularcases，andassertthatcontractedfeet，withthenumerouscontingentevils，ofring—bones，curbs，splints，spavin，founderandweaknessofthefrontlegs，roaringorbrokenandthickwind，melanosis，specificophthalmia，andblindness（thegreatFrenchveterinaryHuzardgoingsofarastosaythatablindracecouldsoonbeformed），crib—biting，jibbingandill—temper，areallplainlyhereditary。Youattsumsupbysaying\"thereisscarcelyamaladytowhichthehorseissubjectwhichisnothereditary;\"andM。
Bernardaddsthatthedoctrine\"thatthereisscarcelyadiseasewhichdoesnotruninthestock，isgainingnewadvocateseveryday。\"（12/21。Thesevariousstatementsaretakenfromthefollowingworksandpapers:——Youatton’TheHorse’pages35，220。Lawrence’TheHorse’page30。Karkeekinanexcellentpaperin’Gard。Chronicle’1853page92。Mr。Burkein’JournalofR。Agricul。Soc。ofEngland’volume5page511。’Encyclop。ofRuralSports’
page279。GiroudeBuzareingues’Philosoph。Phys。’page215。Seefollowingpapersin’TheVeterinary;’Robertsinvolume2page144;M。Marrimpoeyvolume2page387;Mr。Karkeekvolume4page5;YouattonGoitrein’Dogs’
volume5page483:Youattinvolume6pages66，348，412;M。Bernardvolume11page539;Dr。Samesreutheron’Cattle’involume12page181;Percivallinvolume13page47。WithrespecttoblindnessinhorsesseealsoawholerowofauthoritiesinDr。P。Lucas’sgreatwork，tome1page399。Mr。Bakerin’TheVeterinary’volume13page721，givesastrongcaseofhereditaryimperfectvisionandofjibbing。）Soitisinregardtocattle，withconsumption，goodandbadteeth，fineskin，etc。etc。Butenough，andmorethanenough，hasbeensaidondisease。AndrewKnight，fromhisownexperience，assertsthatdiseaseishereditarywithplants;andthisassertionisendorsedbyLindley。（12/22。Knighton’TheCultureoftheAppleandPear’page34。Lindley’s’Horticulture’page180。）
Seeinghowhereditaryevilqualitiesare，itisfortunatethatgoodhealth，vigour，andlongevityareequallyinherited。Itwasformerlyawell—knownpractice，whenannuitieswerepurchasedtobereceivedduringthelife—timeofanominee，tosearchoutapersonbelongingtoafamilyofwhichmanymembershadlivedtoextremeoldage。Astotheinheritanceofvigourandendurance，theEnglishrace—horseoffersanexcellentinstance。Eclipsebegot334，andKingHerod497winners。A\"cock—tail\"isahorsenotpurelybred，butwithonlyone—eighth，orone—sixteenthimpurebloodinhisveins，yetveryfewinstanceshaveeveroccurredofsuchhorseshavingwonagreatrace。Theyaresometimesasfleetforshortdistancesasthoroughbreds，butasMr。Robson，thegreattrainer，asserts，theyaredeficientinwind，andcannotkeepupthepace。Mr。Lawrencealsoremarks，\"perhapsnoinstancehaseveroccurredofathree—part—bredhorsesavinghis’DISTANCE’inrunningtwomileswiththoroughbredracers。\"IthasbeenstatedbyCecil，thatwhenunknownhorses，whoseparentswerenotcelebrated，haveunexpectedlywongreatraces，asinthecaseofPriam，theycanalwaysbeprovedtobedescended，onbothsides，throughmanygenerations，fromfirst—rateancestors。OntheContinent，BaronCameronnchallenges，inaGermanveterinaryperiodical，theopponentsoftheEnglishrace—horsetonameonegoodhorseontheContinent，whichhasnotsomeEnglishrace—bloodinhisveins。（12/23。Thesestatementsaretakenfromthefollowingworksinorder:——Youatton’TheHorse’page48;Mr。Darvillin’TheVeterinary’
volume8page50。WithrespecttoRobsonsee’TheVeterinary’volume3page580;Mr。Lawrenceon’TheHorse’1829page9;’TheStudFarm’byCecil1851;BaronCameronnquotedin’TheVeterinary’volume10page500。）
Withrespecttothetransmissionofthemanyslight，butinfinitelydiversifiedcharacters，bywhichthedomesticracesofanimalsandplantsaredistinguished，nothingneedbesaid;fortheveryexistenceofpersistentracesproclaimsthepowerofinheritance。
Afewspecialcases，however，deservesomeconsideration。Itmighthavebeenanticipated，thatdeviationsfromthelawofsymmetrywouldnothavebeeninherited。ButAnderson（12/24。’RecreationsinAgricultureandNat。
Hist。’volume1page68。）statesthatarabbitproducedinalitterayounganimalhavingonlyoneear;andfromthisanimalabreedwasformedwhichsteadilyproducedone—earedrabbits。Healsomentionsabitchwithasinglelegdeficient，andsheproducedseveralpuppieswiththesamedeficiency。
FromHofacker’saccount（12/25。’UeberdieEigenschaften’etc。1828s。
107。）itappearsthataone—hornedstagwasseenin1781inaforestinGermany，in1788two，andafterwards，fromyeartoyear，manywereobservedwithonlyonehornontherightsideofthehead。Acowlostahornbysuppuration（12/26。Bronn’GeschichtederNatur’b。2s。132。），andsheproducedthreecalveswhichhadonthesamesideofthehead，insteadofahorn，asmallbonylumpattachedmerelytotheskin;butwehereencroachonthesubjectofinheritedmutilations。Amanwhoisleft—handed，andashellinwhichthespireturnsinthewrongdirections，aredeparturesfromthenormalasymmetricalcondition，andtheyarewell—knowntobeinherited。
[POLYDACTYLISM。
Supernumeraryfingersandtoesareeminentlyliable，asvariousauthorshaveinsisted，tobeinherited。Polydactylismgraduates（12/27。VrolikhasdiscussedthispointatfulllengthinaworkpublishedinDutch，fromwhichSirJ。Pagethaskindlytranslatedformepassages。See，also，IsidoreGeoffroySt。Hilaire’Hist。desAnomalies’1832tome1page684。）
bymultifariousstepsfromamerecutaneousappendage，notincludinganybone，toadoublehand。Butanadditionaldigit，supportedonametacarpalbone，andfurnishedwithallthepropermuscles，nerves，andvessels，issometimessoperfect，thatitescapesdetection，unlessthefingersareactuallycounted。Occasionallythereareseveralsupernumerarydigits;butusuallyonlyone，makingthetotalnumbersix。Thisonemaybeattachedtotheinneroroutermarginofthehand，representingeitherathumborlittlefinger，thelatterbeingthemorefrequent。Generally，throughthelawofcorrelation，bothhandsandbothfeetaresimilarlyaffected。Dr。
BurtWilderhastabulated（12/28。’MassachusettsMedicalSociety’volume2
No。3;and’Proc。BostonSoc。ofNat。Hist。’volume141871page154。）alargenumberofcases，andfindsthatsupernumerarydigitsaremorecommononthehandsthanonthefeet，andthatmenareaffectedoftenerthanwomen。Boththesefactscanbeexplainedontwoprincipleswhichseemgenerallytoholdgood;firstly，thatoftwoparts，themorespecialisedoneisthemorevariable，andthearmismorehighlyspecialisedthantheleg;andsecondlythatmaleanimalsaremorevariablethanfemales。
Thepresenceofagreaternumberofdigitsthanfiveisagreatanomaly，forthisnumberisnotnormallyexceededbyanyexistingmammal，bird，orreptile。Nevertheless，supernumerarydigitsarestronglyinherited;theyhavebeentransmittedthroughfivegenerations;andinsomecases，afterdisappearingforone，two，oreventhreegenerations，havereappearedthroughreversion。Thesefactsarerendered，asProfessorHuxleyhasobserved，moreremarkablefromitsbeingknowninmostcasesthattheaffectedpersonhasnotmarriedonesimilarlyaffected。Insuchcasesthechildofthefifthgenerationwouldhaveonly1—32ndpartofthebloodofhisfirstsedigitatedancestor。Othercasesarerenderedremarkablebytheaffectiongatheringforce，asDr。Struthershasshown，ineachgeneration，thoughineachtheaffectedpersonmarriedonenotaffected;moreover，suchadditionaldigitsareoftenamputatedsoonafterbirth，andcanseldomhavebeenstrengthenedbyuse。Dr。Struthersgivesthefollowinginstance:inthefirstgenerationanadditionaldigitappearedononehand;inthesecond，onbothhands;inthethird，threebrothershadbothhands，andoneofthebrothersafootaffected;andinthefourthgenerationallfourlimbswereaffected。Yetwemustnotover—estimatetheforceofinheritance。Dr。Struthersassertsthatcasesofnon—inheritanceandofthefirstappearanceofadditionaldigitsinunaffectedfamiliesaremuchmorefrequentthancasesofinheritance。Manyotherdeviationsofstructure，ofanaturealmostasanomalousassupernumerarydigits，suchasdeficientphalanges（12/29。Dr。J。W。Oglegivesacaseoftheinheritanceofdeficientphalangesduringfourgenerations。Headdsreferencestovariousrecentpapersoninheritance’Brit。andFor。Med。—Chirurg。Review’April1872。），thickenedjoints，crookedfingers，etc。，are，inlikemanner，stronglyinherited，andareequallysubjecttointermission，togetherwithreversion，thoughinsuchcasesthereisnoreasontosupposethatbothparentshadbeensimilarlyaffected。（12/30。FortheseseveralstatementsseeDr。Struthers’EdinburghNewPhil。Journal’July1863especiallyonintermissionsinthelineofdescent。Prof。Huxley’LecturesonourKnowledgeofOrganicNature’1863page97。Withrespecttoinheritance，seeDr。ProsperLucas’L’HerediteNat。’tome1page325。Isid。Geoffroy’Anom。’
tome1page701。SirA。Carlislein’Phil。Transact。’1814page94。A。
Walkeron’Intermarriage’1838page140givesacaseoffivegenerations;
asdoesMr。Sedgwickin’Brit。andForeignMedico—Chirurg。Review’April1863page462。OntheinheritanceofotheranomaliesintheextremitiesseeDr。H。Dobellinvolume46ofMedico—Chirurg。Transactions1863;alsoMr。
Sedgwickinop。cit。April1863page460。WithrespecttoadditionaldigitsinthenegroseePrichard’PhysicalHistoryofMankind。’Dr。Dieffenbach’Jour。RoyalGeograph。Soc。’1841page208saysthisanomalyisnotuncommonwiththePolynesiansoftheChathamIslands;andIhaveheardofseveralcaseswithHindusandArabs。）
Additionaldigitshavebeenobservedinnegroesaswellasinotherracesofman，andinseveraloftheloweranimals，andhavebeeninherited。Sixtoeshavebeendescribedonthehindfeetofthenewt（Salamandracristata），andaresaidtohaveoccurredwiththefrog。Itdeservesnotice，thatthesix—toednewt，thoughadult，preservedsomeofitslarvalcharacters;forpartofthehyoidalapparatus，whichisproperlyabsorbedduringtheactofmetamorphosis，wasretained。Itisalsoremarkablethatinthecaseofmanvariousstructuresinanembryonicorarrestedstateofdevelopment，suchasacleft—palate，bifiduterus，etc。，areoftenaccompaniedbypolydactylism。（12/31。MeckelandIsidG。St。Hilaireinsistonthisfact。SeealsoM。A。Roujou’SurquelquesAnalogiesduTypeHumain’
page61published，Ibelieve，inthe’JournaloftheAnthropolog。Soc。ofParis’January1872。）Sixtoesonthehinderfeetareknowntohavebeeninheritedforthreegenerationsofcats。Inseveralbreedsofthefowlthehindertoeisdouble，andisgenerallytransmittedtruly，asiswellshownwhenDorkingsarecrossedwithcommonfour—toedbreeds（12/32。’ThePoultryChronicle’1854page559。）Withanimalswhichhaveproperlylessthanfivedigits，thenumberissometimesincreasedtofive，especiallyonthefrontlegs，thoughrarelycarriedbeyondthatnumber;butthisisduetothedevelopmentofadigitalreadyexistinginamoreorlessrudimentarystate。Thus，thedoghasproperlyfourtoesbehind，butinthelargerbreedsafifthtoeiscommonly，thoughnotperfectly，developed。Horses，whichproperlyhaveonetoealonefullydevelopedwithrudimentsoftheothers，havebeendescribedwitheachfootbearingtwoorthreesmallseparatehoofs:analogousfactshavebeennoticedwithcows，sheep，goats，andpigs。（12/33。ThestatementsinthisparagrapharetakenfromIsidoreGeoffroySt。Hilaire’Hist。desAnomalies’tome1pages688—693。Mr。
Goodmangives，’Phil。Soc。ofCambridge’November25，1872thecaseofacowwiththreewelldevelopedtoesoneachhindlimb，besidestheordinaryrudiments;andhercalfbyanordinarybullhadextradigits。Thiscalfalsoboretwocalveshavingextradigits。）
ThereisafamouscasedescribedbyMr。Whiteofachild，threeyearsold，withathumbdoublefromthefirstjoint。Heremovedthelesserthumb，whichwasfurnishedwithanail;buttohisastonishmentitgrewagainandreproducedanail。ThechildwasthentakentoaneminentLondonsurgeon，andthenewly—grownthumbwasremovedbyitssocket—joint，butagainitgrewandreproducedanail。Dr。Struthersmentionsacaseofthepartialregrowthofanadditionalthumb，amputatedwhenachildwasthreemonthsold;andthelateDr。Falconercommunicatedtomeananalogousinstance。InthelasteditionofthisworkIalsogaveacaseoftheregrowthofasupernumerarylittle—fingerafteramputation;buthavingbeeninformedbyDr。Bachmaierthatseveraleminentsurgeonsexpressed，atameetingoftheAnthropologicalSocietyofMunich，greatdoubtaboutmystatements，Ihavemademoreparticularinquiries。Thefullinformationthusgained，togetherwithatracingofthehandinitspresentstate，hasbeenlaidbeforeSirJ。Paget，andhehascometotheconclusionthatthedegreeofregrowthinthiscaseisnotgreaterthansometimesoccurswithnormalbones，especiallywiththehumerus，whenamputatedatanearlyage。HefurtherdoesnotfeelfullysatisfiedaboutthefactsrecordedbyMr。White。Thisbeingso，itisnecessaryformetowithdrawtheviewwhichIformerlyadvanced，withmuchhesitation，chieflyonthegroundofthesupposedregrowthofadditionaldigits，namely，thattheiroccasionaldevelopmentinmanisacaseofreversiontoalowly，organisedprogenitorprovidedwithmorethanfivedigits。]
Imayherealludetoaclassoffactscloselyalliedto，butsomewhatdifferentfrom，ordinarycasesofinheritance。SirH。Holland（12/34。
’MedicalNotesandReflections’1839pages24，34。SeealsoDr。P。Lucas’L’Hered。Nat。’tome2page33。）statesthatbrothersandsistersofthesamefamilyarefrequentlyaffected，oftenataboutthesameage，bythesamepeculiardisease，notknowntohavepreviouslyoccurredinthefamily。
Hespecifiestheoccurrenceofdiabetesinthreebrothersundertenyearsold;healsoremarksthatchildrenofthesamefamilyoftenexhibitincommoninfantilediseases，thesamepeculiarsymptoms。Myfathermentionedtomethecaseoffourbrotherswhodiedbetweentheagesofsixtyandseventy，inthesamehighlypeculiarcomatosestate。Aninstancehasalreadybeengivenofsupernumerarydigitsappearinginfourchildrenoutofsixinapreviouslyunaffectedfamily。Dr。Devaystates（12/35。’DuDangerdesMariagesConsanguins’2ndedition1862page103。）thattwobrothersmarriedtwosisters，theirfirst—cousins，noneofthefournoranyrelationbeinganalbino;butthesevenchildrenproducedfromthisdoublemarriagewereallperfectalbinoes。Someofthesecases，asMr。Sedgwick（12/36。’BritishandForeignMedico—Chirurg。Review’July1863pages183，189。）hasshown，areprobablytheresultofreversiontoaremoteancestor，ofwhomnorecordhadbeenpreserved;andallthesecasesaresofardirectlyconnectedwithinheritancethatnodoubtthechildreninheritedasimilarconstitutionfromtheirparents，and，frombeingexposedtonearlysimilarconditionsoflife，itisnotsurprisingthattheyshouldbeaffectedinthesamemannerandatthesameperiodoflife。
Mostofthefactshithertogivenhaveservedtoillustratetheforceofinheritance，butwemustnowconsidercasesgroupedaswellasthesubjectallowsintoclasses，showinghowfeeble，capricious，ordeficientthepowerofinheritancesometimesis。Whenanewpeculiarityfirstappears，wecanneverpredictwhetheritwillbeinherited。Ifbothparentsfromtheirbirthpresentthesamepeculiarity，theprobabilityisstrongthatitwillbetransmittedtoatleastsomeoftheiroffspring。Wehaveseenthatvariegationistransmittedmuchmorefeeblybyseed，takenfromabranchwhichhadbecomevariegatedthroughbud—variation，thanfromplantswhichwerevariegatedasseedlings。Withmostplantsthepoweroftransmissionnotoriouslydependsonsomeinnatecapacityintheindividual:thusVilmorin（12/37。Verlot’LaProduct。desVarietes’1865page32。）raisedfromapeculiarlycolouredbalsamsomeseedlings，whichallresembledtheirparent;butoftheseseedlingssomefailedtotransmitthenewcharacter，whilstotherstransmittedittoalltheirdescendantsduringseveralsuccessivegenerations。Soagainwithavarietyoftherose，twoplantsaloneoutofsixwerefoundbyVilmorintobecapableoftransmittingthedesiredcharacter;numerousanalogouscasescouldbegiven。
[Theweepingorpendulousgrowthoftreesisstronglyinheritedinsomecases，and，withoutanyassignablereason，feeblyinothercases。Ihaveselectedthischaracterasaninstanceofcapriciousinheritance，becauseitiscertainlynotpropertotheparent—species，andbecause，bothsexesbeingborneonthesametree，bothtendtotransmitthesamecharacter。
Evensupposingthattheremayhavebeeninsomeinstancescrossingwithadjoiningtreesofthesamespecies，itisnotprobablethatalltheseedlingswouldhavebeenthusaffected。AtMoccasCourtthereisafamousweepingoak;manyofitsbranches\"are30feetlong，andnothickerinanypartofthislengththanacommonrope:\"thistreetransmitsitsweepingcharacter，inagreaterorlessdegree，toallitsseedlings;someoftheyoungoaksbeingsoflexiblethattheyhavetobesupportedbyprops;
othersnotshowingtheweepingtendencytillabouttwentyyearsold。
（12/38。Loudon’s’Gardener’sMag。’volume121836page368。）Mr。Riversfertilised，asheinformsme，theflowersofanewBelgianweepingthorn（Crataegusoxyacantha）withpollenfromacrimsonnot—weepingvariety，andthreeyoungtrees，\"nowsixorsevenyearsold，showadecidedtendencytobependulous，butasyetarenotsomuchsoasthemother—plant。\"AccordingtoMr。MacNab（12/39。Verlot’LaProduct。desVarietes’1865page94。），seedlingsfromamagnificentweepingbirch（Betulaalba），intheBotanicGardenatEdinburgh，grewforthefirsttenorfifteenyearsupright，butthenallbecameweepersliketheirparent。Apeachwithpendulousbranches，likethoseoftheweepingwillow，hasbeenfoundcapableofpropagationbyseed。（12/40。Bronn’GeschichtederNatur’b。2s。121。Mr。Meehanmakesasimilarstatementin’Proc。Nat。ofPhiladelphia’1872page235。）Lastly，aweepingorratheraprostrateyew（Taxusbaccata）wasfoundinahedgeinShropshire;itwasamale，butonebranchborefemaleflowers，andproducedberries;these，beingsown，producedseventeentreesallofwhichhadexactlythesamepeculiarhabitwiththeparent—tree。（12/41。Rev。W。A。
Leighton’FloraofShropshire’page497;andCharlesworth’Mag。ofNat。
Hist。’volume11837page30。Ipossessprostratetreesproducedfromtheseseeds。）
Thesefacts，itmighthavebeenthought，wouldhavebeensufficienttorenderitprobablethatapenduloushabitwouldinallcasesbestrictlyinherited。Butletuslooktotheotherside。Mr。MacNab（12/42。Verlotop。
cit。page93。）sowedseedsoftheweepingbeech（Fagussylvatica），butsucceededinraisingonlycommonbeeches。Mr。Rivers，atmyrequest，raisedanumberofseedlingsfromthreedistinctvarietiesofweepingelm;andatleastoneoftheparent—treeswassosituatedthatitcouldnothavebeencrossedbyanyotherelm;butnoneoftheyoungtrees，nowaboutafootortwoinheight，showtheleastsignsofweeping。Mr。Riversformerlysowedabovetwentythousandseedsoftheweepingash（Fraxinusexcelsior），andnotasingleseedlingwasintheleastdegreependulous:inGermany，M。
Borchmeyerraisedathousandseedlings，withthesameresult。Nevertheless，Mr。Anderson，oftheChelseaBotanicGarden，bysowingseedfromaweepingash，whichwasfoundbeforetheyear1780，inCambridgeshire，raisedseveralpenduloustrees。（12/43。FortheseseveralstatementsseeLoudon’s’Gard。Magazine’volume101834pages408，180;andvolume91833page597。）ProfessorHenslowalsoinformsmethatsomeseedlingsfromafemaleweepingashintheBotanicGardenatCambridgewereatfirstalittlependulous，butafterwardsbecamequiteupright:itisprobablethatthislattertree，whichtransmitstoacertainextentitspenduloushabit，wasderivedbyabudfromthesameoriginalCambridgeshirestock;whilstotherweepingashesmayhavehadadistinctorigin。Butthecrowningcase，communicatedtomebyMr。Rivers，whichshowshowcapriciousistheinheritanceofapenduloushabit，isthatavarietyofanotherspeciesofash（F。lentiscifolia），nowabouttwentyyearsold，whichwasformerlypendulous，\"haslonglostthishabit，everyshootbeingremarkablyerect;
butseedlingsformerlyraisedfromitwereperfectlyprostrate，thestemsnotrisingmorethantwoinchesabovetheground。\"Thustheweepingvarietyofthecommonash，whichhasbeenextensivelypropagatedbybudsduringalongperiod，didnotwithMr。Rivers，transmititscharactertooneseedlingoutofabovetwentythousand;whereastheweepingvarietyofasecondspeciesofash，whichcouldnot，whilstgrowninthesamegarden，retainitsownweepingcharacter，transmittedtoitscharacterthependuloushabitinexcess！
Manyanalogousfactscouldbegiven，showinghowapparentlycapriciousistheprincipleofinheritance。AlltheseedlingsfromavarietyoftheBarberry（B。vulgaris）withredleavesinheritedthesamecharacter;onlyaboutone—thirdoftheseedlingsofthecopperBeech（Fagussylvatica）hadpurpleleaves。NotoneoutofahundredseedlingsofavarietyoftheCerasuspadus，withyellowfruit，boreyellowfruit:one—twelfthoftheseedlingsofthevarietyofCornusmascula，withyellowfruit，cametrue（12/44。ThesestatementsaretakenfromAlph。DeCandolle’Bot。Geograph。’
page1083。）:andlastly，allthetreesraisedbymyfatherfromayellow—
berriedholly（Ilexaquifolium），foundwild，producedyellowberries。
Vilmorin（12/45。Verlotop。cit。page38。）observedinabedofSaponariacalabricaanextremelydwarfvariety，andraisedfromitalargenumberofseedlings;someofthesepartiallyresembledtheirparent，andheselectedtheirseed;butthegrandchildrenwerenotintheleastdwarfed:ontheotherhand，heobservedastuntedandbushyvarietyofTagetessignatagrowinginthemidstofthecommonvarietiesbywhichitwasprobablycrossed;formostoftheseedlingsraisedfromthisplantwereintermediateincharacter，onlytwoperfectlyresemblingtheirparent;butseedsavedfromthesetwoplantsreproducedthenewvarietysotruly，thathardlyanyselectionhassincebeennecessary。
Flowerstransmittheircolourtruly，ormostcapriciously。Manyannualscometrue:thusIpurchasedGermanseedsofthirty—fournamedsub—varietiesofoneRACEoften—weekstocks（Matthiolaannua），andraisedahundredandfortyplants，allofwhich，withtheexceptionofasingleplant，cametrue。Insayingthis，however，itmustbeunderstoodthatIcoulddistinguishonlytwentykindsoutofthethirty—fournamedsub—varieties;
nordidthecolourofthefloweralwayscorrespondwiththenameaffixedtothepacket;butIsaythattheycametrue，becauseineachofthethirty—
sixshortrowseveryplantwasabsolutelyalike，withtheonesingleexception。Again，IprocuredpacketsofGermanseedoftwenty—fivenamedvarietiesofcommonandquilledasters，andraisedahundredandtwenty—
fourplants;ofthese，allexcepttenweretrueintheabovelimitedsense;
andIconsideredevenawrongshadeofcolourasfalse。
Itisasingularcircumstancethatwhitevarietiesgenerallytransmittheircolourmuchmoretrulythananyothervariety。ThisfactprobablystandsincloserelationwithoneobservedbyVerlot（12/46。Op。cit。page59。），namely，thatflowerswhicharenormallywhiterarelyvaryintoanyothercolour。IhavefoundthatthewhitevarietiesofDelphiniumconsolidaandoftheStockarethetruest。Itis，indeed，sufficienttolookthroughanurseryman’sseed—list，toseethelargenumberofwhitevarietieswhichcanbepropagatedbyseed。Theseveralcolouredvarietiesofthesweet—pea（Lathyrusodoratus）areverytrue;butIhearfromMr。Masters，ofCanterbury，whohasparticularlyattendedtothisplant，thatthewhitevarietyisthetruest。Thehyacinth，whenpropagatedbyseed，isextremelyinconstantincolour，but\"whitehyacinthsalmostalwaysgivebyseedwhite—floweredplants\"（12/47。Alph。DeCandolle’Geograph。Bot。’page1082。）;andMr。Mastersinformsmethattheyellowvarietiesalsoreproducetheircolour，butofdifferentshades。Ontheotherhand，pinkandbluevarieties，thelatterbeingthenaturalcolour，arenotnearlysotrue:
hence，asMr。Mastershasremarkedtome，\"weseethatagardenvarietymayacquireamorepermanenthabitthananaturalspecies;\"butitshouldhavebeenadded，thatthisoccursundercultivation，andthereforeunderchangedconditions。
Withmanyflowers，especiallyperennials，nothingcanbemorefluctuatingthanthecolouroftheseedlings，asisnotoriouslythecasewithverbenas，carnations，dahlias，cinerarias，andothers。（12/48。See’CottageGardener’
April10，1860page18andSeptember10，1861page456;’Gardener’sChronicle’1845page102。）IsowedseedoftwelvenamedvarietiesofSnapdragon（Antirrhinummajus），andutterconfusionwastheresult。Inmostcasestheextremelyfluctuatingcolourofseedlingplantsisprobablyinchiefpartduetocrossesbetweendifferently—colouredvarietiesduringpreviousgenerations。Itisalmostcertainthatthisisthecasewiththepolyanthusandcolouredprimrose（Primulaverisandvulgaris），fromtheirreciprocallydimorphicstructure（12/49。Darwinin’JournalofProc。Linn。