Genesis，pp。300and306；alsoSchrader；forSt。Basil，seeHexaemeronandHomiliesvii-ix；butforthesteadfastnessofBasil’sviewinregardtotheimmutabilityofspecies，seeaCatholicwriteronevolutionandFaithintheDublinReviewforJuly，1871，p。13；forcitationsofSt。AugustineonGenesis，seetheDeGenesicontraManichoeos，lib。ii，cap。14，inMigne，xxxiv，188，——lib。v，cap。5andcap。23，——andlibvii，capI；forthecitationsfromhisworkontheTrinity，seehisDeTrinitate，lib。iii，cap。8and9，inMigne，xlii，877，878；forthegeneralsubjectveryfullyandadequatelypresented，seeOsborn，FromtheGreekstoDarwin，NewYork，1894，chaps。iiandiii。
Thisideaofadevelopmentbysecondarycausesapartfromtheoriginalcreationwashelpedinitsgrowthbyatheologicalexigency。Moreandmore，astheorganicworldwasobserved，thevastmultitudeofpettyanimals，wingedcreatures，and“creepingthings“wasfelttobeastrainuponthesacrednarrative。MoreandmoreitbecamedifficulttoreconcilethedignityoftheAlmightywithhisworkinbringingeachofthesecreaturesbeforeAdamtobenamed；ortoreconcilethehumanlimitationsofAdamwithhisworkinnaming“everylivingcreature“；ortoreconcilethedimensionsofNoah’sarkwiththespacerequiredforpreservingallofthem，andthefoodofallsortsnecessaryfortheirsustenance，whethertheywereadmittedbytwos，asstatedinonescripturalaccount，orbysevens，asstatedintheother。
Theinadequatesizeofthearkgaveespecialtrouble。Origenhaddealtwithitbysuggestingthatthecubitwassixtimesgreaterthanhadbeensupposed。BedeexplainedNoah’sabilitytocompletesolargeavesselbysupposingthatheworkeduponitduringahundredyears；and，astotheprovisionoffoodtakenintoit，hedeclaredthattherewasnoneedofasupplyformorethanoneday，sinceGodcouldthrowtheanimalsintoadeepsleeporotherwisemiraculouslymakeoneday’ssupplysufficient；healsolessenedthestrainonfaithstillmorebydiminishingthenumberofanimalstakenintotheark——supportinghisviewuponAugustine’stheoryofthelaterdevelopmentofinsectsoutofcarrion。
DoubtlessthistheologicalnecessitywasamongthemainreasonswhichledSt。IsidoreofSeville，intheseventhcentury，toincorporatethistheory，supportedbySt。BasilandSt。
Augustine，intohisgreatencyclopedicworkwhichgavematerialsforthoughtonGodandNaturetosomanygenerations。Hefamiliarizedthetheologicalworldstillfurtherwiththedoctrineofsecondarycreation，givingsuchexamplesofitasthat“beesaregeneratedfromdecomposedveal，beetlesfromhorseflesh，grasshoppersfrommules，scorpionsfromcrabs。”and，inordertogivestillstrongerforcetotheideaofsuchtransformations，hedwellsonthebiblicalaccountofNebuchadnezzar，whichappearstohavetakenstrongholduponmedievalthoughtinscience，andhedeclaresthatotherhumanbeingshadbeenchangedintoanimals，especiallyintoswine，wolves，andowls。