Howlongatimeitwouldrequirebeforesuchacrossedbodyofanimalswouldassumeauniformcharacterwithinalimitedarea，noonecansay;thattheywouldultimatelybecomeuniformfromfreeintercrossing，andfromthesurvivalofthefittest，wemayfeelassured;butthecharactersthusacquiredwouldrarelyornever，asmaybeinferredfromthepreviousconsiderations，beexactlyintermediatebetweenthoseofthetwoparent—breeds。Withrespecttotheveryslightdifferencesbywhichtheindividualsofthesamesub—variety，orevenofalliedvarieties，arecharacterised，itisobviousthatfreecrossingwouldsoonobliteratesuchsmalldistinctions。Theformationofnewvarieties，independentlyofselection，wouldalsothusbeprevented;exceptwhenthesamevariationcontinuallyrecurredfromtheactionofsomestronglypredisposingcause。Wemaythereforeconcludethatfreecrossinghasinallcasesplayedanimportantpartingivinguniformityofcharactertoallthemembersofthesamedomesticraceandofthesamenaturalspecies，thoughlargelygovernedbynaturalselectionandbythedirectactionofthesurroundingconditions。
ONTHEPOSSIBILITYOFALLORGANICBEINGSOCCASIONALLYINTERCROSSING。
Butitmaybeasked，canfreecrossingoccurwithhermaphroditeanimalsandplants？Allthehigheranimals，andthefewinsectswhichhavebeendomesticated，haveseparatesexes，andmustinevitablyuniteforeachbirth。
Withrespecttothecrossingofhermaphrodites，thesubjectistoolargeforthepresentvolume，butinthe’OriginofSpecies’Ihavegivenashortabstractofthereasonswhichinducemetobelievethatallorganicbeingsoccasionallycross，thoughperhapsinsomecasesonlyatlongintervalsoftime。（15/14。Withrespecttoplants，anadmirableessayonthissubject（DieGeschlechter—VertheilungbeidenPflanzen:1867）hasbeenpublishedbyDr。
HildebrandwhoarrivesatthesamegeneralconclusionsasIhavedone。Variousothertreatiseshavesinceappearedonthesamesubject，moreespeciallybyHermannMullerandDelpino。）Iwillmerelyrecallthefactthatmanyplants，thoughhermaphroditeinstructure，areunisexualinfunction;——suchasthosecalledbyC。K。SprengelDICHOGAMOUS，inwhichthepollenandstigmaofthesameflowerarematuredatdifferentperiods;orthosecalledbymeRECIPROCALLYDIMORPHIC，inwhichtheflower’sownpollenisnotfittedtofertiliseitsownstigma;oragain，themanykindsinwhichcuriousmechanicalcontrivancesexist，effectuallypreventingself—fertilisation。Thereare，however，manyhermaphroditeplantswhicharenotinanywayspeciallyconstructedtofavourintercrossing，butwhichneverthelesscomminglealmostasfreelyasanimalswithseparatedsexes。Thisisthecasewithcabbages，radishes，andonions，asIknowfromhavingexperimentedonthem:eventhepeasantsofLiguriasaythatcabbagesmustbeprevented\"fromfallinginlove\"