The Life of the Fly

第12章

watchedmeatsafe,settlesonourwindowpanesandkeepsupasolemnbuzzing,anxioustobeoffinthesunandripenafreshemissionofgerms。Howdoesshelayhereggs,theoriginoftheloathsomemaggotthatbattenspoisonouslyonourprovisions,whetherofgameorbutcher’smeat?Whatareherstratagemsandhowcanwefoilthem?ThisiswhatIproposetoinvestigate。

Thebluebottlefrequentsourhomesduringautumnandapartofwinter,untilthecoldbecomessevere;butherappearanceinthefieldsdatesbackmuchearlier。OnthefirstfinedayinFebruary,weshallseeherwarmingherself,chillily,againstthesunnywalls。InApril,Inoticeherinconsiderablenumbersonthelaurestinus。Itisherethatsheseemstopair,whilesippingthesugaryexudationsofthesmallwhiteflowers。Thewholeofthesummerseasonisspentoutofdoors,inbriefflightsfromonerefreshmentbartothenext。Whenautumncomes,withitsgame,shemakesherwayintoourhousesandremainsuntilthehardfrosts。

Thissuitsmystay—at—homehabitsandespeciallymylegs,whicharebendingundertheweightofyears。Ineednotrunafterthesubjectsofmypresentstudy;theycallonme。Besides,Ihavevigilantassistants。Thehouseholdknowsofmyplans。Everyonebringsme,inalittlescrewofpaper,thenoisyvisitorjustcapturedagainstthepanes。

ThusdoIfillmyvivarium,whichconsistsofalarge,bell—shapedcageofwiregauze,standinginanearthenwarepanfullofsand。A

mugcontaininghoneyisthediningroomoftheestablishment。Herethecaptivescometorecruitthemselvesintheirhoursofleisure。

Tooccupytheirmaternalcares,Iemploysmallbirds——chaffinches,linnets,sparrows——broughtdown,intheenclosure,bymyson’sgun。

IhavejustservedupaLinnetshottwodaysago。Inextplaceinthecageabluebottle,oneonly,toavoidconfusion。Herfatbellyproclaimstheadventofalayingtime。Anhourlater,whentheexcitementofbeingputinprisonisallayed,mycaptiveisinlabor。Witheager,jerkysteps,sheexploresthemorselofgame,goesfromtheheadtothetail,returnsfromthetailtothehead,repeatstheactionseveraltimesandatlastsettlesnearaneye,adimmedeyesunkintoitssocket。

Theovipositorbendsatarightangleanddivesintothejunctionofthebeak,straightdowntotheroot。Thentheeggsareemittedfornearlyhalfanhour。Thelayer,utterlyabsorbedinherseriousbusiness,remainsstationaryandimpassiveandiseasilyobservedthroughmylens。Amovementonmypartwoulddoubtlessscareher;butmyrestfulpresencegiveshernoanxiety。Iamnothingtoher。

Thedischargedoesnotgooncontinuouslyuntiltheovariesareexhausted;itisintermittentandperformedinsomanypackets。

Severaltimesover,theflyleavesthebird’sbeakandcomestotakearestuponthewiregauze,whereshebrushesherhindlegsoneagainsttheother。Inparticular,beforeusingitagain,shecleans,smoothesandpolishesherlayingtool,theprobethatplacestheeggs。Then,feelingherwombstillteeming,shereturnstothesamespotatthejointofthebeak。Thedeliveryisresumed,toceasepresentlyandthenbeginanew。Acoupleofhoursarethusspentinalternatestandingneartheeyeandrestingonthewiregauze。

Atlast,itisover。Theflydoesnotgobacktothebird,aproofthatherovariesareexhausted。Thenextday,sheisdead。Theeggsaredabbedinacontinuouslayer,attheentrancetothethroat,attherootofthetongue,onthemembraneofthepalate。

Theirnumberappearsconsiderable;thewholeinsideofthegulletiswhitewiththem。Ifixalittlewoodenpropbetweenthetwomandiblesofthebeak,tokeepthemopenandenablemetoseewhathappens。

Ilearninthiswaythatthehatchingtakesplaceinacoupleofdays。Assoonastheyareborn,theyoungvermin,aswarmingmass,leavetheplacewheretheyareanddisappeardownthethroat。Toinquirefurtherintotheworkisuselessforthemoment。Weshalllearnmoreaboutitlater,underconditionsthatmakeexaminationeasier。

Thebeakofthebirdinvadedwasclosedatthestart,asfarasthenaturalcontactofthemandiblesallowed。Thereremainedanarrowslitatthebase,sufficientatmosttoadmitthepassageofahorsehair。Itwasthroughthisthatthelayingwasperformed。

Lengtheningherovipositorlikeatelescope,themotherinsertedthepointofherimplement,apointslightlyhardenedwithahornyarmor。Thefinenessoftheprobeequalsthefinenessoftheaperture。But,ifthebeakwereentirelyclosed,wherewouldtheeggsbelaidthen?

Withatiedthread,Ikeepthetwomandiblesinabsolutecontact;

andIplaceasecondbluebottleinthepresenceofthelinnet,whichthecolonistshavealreadyenteredbythebeak。Thistime,thelayingtakesplaceononeoftheeyes,betweenthelidandtheeyeball。Atthehatching,whichagainoccursacoupleofdayslater,thegrubsmaketheirwayintothefleshydepthsofthesocket。Theeyesandthebeak,therefore,formthetwochiefentrancesintofeatheredgame。

Thereareothers;andthesearethewounds。Icoverthelinnet’sheadwithapaperhoodwhichwillpreventinvasionthroughthebeakandeyes。Iserveit,underthewiregauzebell,toathirdegglayer。Thebirdhasbeenstruckbyashotinthebreast,butthesoreisnotbleeding:noouterstainmarkstheinjuredspot。

Moreover,Iamcarefultoarrangethefeathers,tosmooththemwithahairpencil,sothatthebirdlooksquitesmartandhaseveryappearanceofbeinguntouched。

Theflyissoonthere。Sheinspectsthelinnetfromendtoend;

withherfronttarsishefumblesatthebreastandbelly。Itisasortofauscultationbysenseoftouch。Theinsectbecomesawareofwhatisunderthefeathersbythemannerinwhichthesereact。

Ifscentcomestoherassistance,itcanonlybeveryslightly,forthegameisnotyethigh。Thewoundissoonfound。Nodropofbloodisnearit,foritisclosedbyaplugofdownrammedintoitbytheshot。Theflytakesupherpositionwithoutseparatingthefeathersoruncoveringthewound。Sheremainsherefortwohourswithoutstirring,motionless,withherabdomenconcealedbeneaththeplumage。Myeagercuriositydoesnotdistractherfromherbusinessforamoment。

Whenshehasfinished,Itakeherplace。Thereisnothingeitherontheskinoratthemouthofthewound。Ihavetowithdrawthedownypluganddigtosomedepthbeforediscoveringtheeggs。Theovipositorhasthereforelengtheneditsextensibletubeandpushedbeyondthefeatherstopperdriveninbythelead。Theeggsareinonepacket;theynumberaboutthreehundred。

Whenthebeakandeyesarerenderedinaccessible,whenthebody,moreover,hasnowounds,thelayingstilltakesplace,but,thistime,inahesitatingandniggardlyfashion。Ipluckthebirdcompletely,thebettertowatchwhathappens;also,Icovertheheadwithapaperhoodtoclosetheusualmeansofaccess。Foralongtime,withjerkysteps,themotherexploresthebodyineverydirection;shetakesherstandbypreferenceonthehead,whichshesoundsbytappingonitwithherfronttarsi。Sheknowsthattheopeningswhichsheneedsarethere,underthepaper;butshealsoknowshowfrailarehergrubs,howpowerlesstopiercetheirwaythroughthestrangeobstaclewhichstopsheraswellandinterfereswiththeworkofherovipositor。Thecowlinspiresherwithprofounddistrust。Despitethetemptingbaitoftheveiledhead,notaneggislaidonthewrapper,slightthoughitmaybe。

Wearyofvainattemptstocompassthisobstacle,theFlyatlastdecidesinfavorofotherpoints,butnotonthebreast,bellyorback,wherethehidewouldseemtootoughandthelighttoointrusive。Sheneedsdarkhidingplaces,cornerswheretheskinisverydelicate。Thespotschosenarethecavityoftheaxilla,correspondingwithourarmpit,andthecreasewherethethighjoinsthebelly。Eggsarelaidinbothplaces,butnotmany,showingthatthegroinandtheaxillaareadoptedonlyreluctantlyandforlackofabetterspot。

Withanunpluckedbird,alsohooded,thesameexperimentfailed:

thefeatherspreventtheflyfromslippingintothosedeepplaces。

Letusadd,inconclusion,that,onaskinnedbird,orsimplyonapieceofbutcher’smeat,thelayingiseffectedonanypartwhatever,providedthatitbedark。Thegloomiestcornersarethefavoriteones。

Itfollowsfromallthisthat,tolaytheeggs,theBluebottlepicksouteithernakedwoundsorelsethemucousmembranesofthemouthoreyes,whicharenotprotectedbyaskinofanythickness。

Shealsoneedsdarkness。Weshallseethereasonsforherpreferencelateron。

Theperfectefficiencyofthepaperbag,whichpreventstheinroadsofthewormsthroughtheeyesocketsorthebeak,suggestsasimilarexperimentwiththewholebird。Itisamatterofwrappingthebodyinasortofartificialskinwhichwillbeasdiscouragingtotheflyasthenaturalskin。Linnets,somewithdeepwounds,othersalmostintact,areplacedonebyoneinpaperenvelopessimilartothoseinwhichthenurserygardenerkeepshisseeds,envelopesjustfolded,withoutbeingstuck。Thepaperisquiteordinaryandofaveragethickness。Tornpiecesofnewspaperservethepurpose。

Thesesheathswiththecorpsesinsidethemarefreelyexposedtotheair,onthetableinmystudy,wheretheyarevisited,accordingtothetimeofday,indenseshadeandinbrightsunlight。Attractedbytheeffluviafromthedeadmeat,thebluebottleshauntmylaboratory,thewindowsofwhicharealwaysopen。Iseethemdailyalightingontheenvelopesandverybusilyexploringthem,apprisedofthecontentsbythegamysmell。Theirincessantcomingandgoingisasignofintensecupidity;andyetnoneofthemdecidestolayonthebags。Theydonotevenattempttoslidetheirovipositorthroughtheslitsofthefolds。Thefavorableseasonpassesandnotaneggislaidonthetemptingwrappers。Allthemothersabstain,judgingtheslenderobstacleofthepapertobemorethantheverminwillbeabletoovercome。

Thiscautiononthefly’spartdoesnotatallsurpriseme:

motherhoodeverywherehasgleamsofgreatperspicacity。Whatdoesastonishmeisthefollowingresult。Theparcelscontainingthelinnetsareleftforawholeyearuncoveredonthetable;theyremainthereforasecondyearandathird。Iinspectthecontentsfromtimetotime。Thelittlebirdsareintact,withunrumpledfeathers,freefromsmell,dryandlight,likemummies。Theyhavebecomenotdecomposed,butmummified。

Iexpectedtoseethemputrefying,runningintosanies,likecorpseslefttorotintheopenair。Onthecontrary,thebirdshavedriedandhardened,withoutundergoinganychange。Whatdidtheywantfortheirputrefaction?Simplytheinterventionofthefly。Themaggot,therefore,istheprimarycauseofdissolutionafterdeath;itis,aboveall,theputrefactivechemist。

Aconclusionnotdevoidofvaluemaybedrawnfrommypapergamebags。Inourmarkets,especiallyinthoseoftheSouth,thegameishungunprotectedfromthehooksonthestalls。Larksstrungupbythedozenwithawirethroughtheirnostrils,thrushes,plovers,teal,partridges,snipe,inshort,allthegloriesofthespitwhichtheautumnmigrationbringsus,remainfordaysandweeksatthemercyoftheflies。Thebuyerallowshimselftobetemptedbyagoodlyexterior;hemakeshispurchaseand,backathome,justwhenthebirdisbeingpreparedforroasting,hediscoversthatthepromiseddaintyisalivewithworms。Ohorror!Thereisnothingforitbuttothrowtheloathsome,verminousthingaway。

Thebluebottleistheculprithere。Everybodyknowsit;andnobodythinksofseriouslyshakingoffhertyranny:nottheretailer,northewholesaledealer,northekillerofthegame。Whatiswantedtokeepthemaggotsout?Hardlyanything:toslipeachbirdintoapapersheath。Ifthisprecautionweretakenatthestart,beforethefliesarrive,anygamewouldbesafeandcouldbeleftindefinitelytoattainthedegreeofripenessrequiredbytheepicure’spalate。

Stuffedwitholivesandmyrtleberries,theCorsicanblackbirdsareexquisiteeating。WesometimesreceivethematOrange,layersofthem,packedinbasketsthroughwhichtheaircirculatesfreelyandeachcontainedinapaperwrapper。Theyareinastateofperfectpreservation,complyingwiththemostexactingdemandsofthekitchen。Icongratulatethenamelessshipperwhoconceivedthebrightideaofclothinghisblackbirdsinpaper。Willhisexamplefindimitators?Idoubtit。

Thereis,ofcourse,aseriousobjectiontothismethodofpreservation。Initspapershroud,thearticleisinvisible;itisnotenticing;itdoesnotinformthepasserbyofitsnatureandqualities。Thereisoneresourceleftwhichwouldleavethebirduncovered:simplytocasetheheadinapapercap。Theheadbeingthepartmostthreatened,becauseofthemucusmembraneofthethroatandeyes,itwouldbesufficient,asarule,toprotectthehead,inordertokeepofftheFliesandtothwarttheirattempts。

Letuscontinuetostudythebluebottle,whilevaryingourmeansofinformation。Atin,aboutfourinchesdeep,containsapieceofbutcher’smeat。Thelidisnotputinquitestraightandleavesanarrowslitatonepointofitscircumference,allowing,atmost,ofthepassageofafineneedle。Whenthebaitbeginstogiveoffagamyscent,themotherscome。Singlyorinnumbers。Theyareattractedbytheodorwhich,transmittedthroughathincrevice,hardlyreachesmynostrils。

Theyexplorethemetalreceptacleforsometime,seekinganentrance。Findingnaughtthatenablesthemtoreachthecovetedmorsel,theydecidetolaytheireggsonthetin,justbesidetheaperture。Sometimes,whenthewidthofthepassageallowsofit,theyinserttheovipositorintothetinandlaytheeggsinside,ontheveryedgesoftheslit。Whetheroutsideorin,theeggsaredabbeddowninafairlyregularandabsolutelywhitelayer。Iasitwereshovelthemupwithalittlepaperscoop。IthusobtainallthegermsthatIrequireformyexperiments,eggsbearingnotraceofthestainswhichwouldbeinevitableifIhadtocollectthemontaintedmeat。

Wehaveseenthebluebottlerefusingtolayhereggsonthepaperbag,notwithstandingthecarrionfumesoftheLinnetenclosed;yetnow,withouthesitation,shelaysthemonasheetofmetal。Canthenatureofthefloormakeanydifferencetoher?Ireplacethetinlidbyapapercoverstretchedandpastedovertheorifice。

Withthepointofmyknife,Imakeanarrowslitinthisnewlid。

Thatisquiteenough:theparentacceptsthepaper。

Whatdeterminedher,therefore,isnotsimplythesmell,whichcaneasilybeperceivedeventhroughtheuncutpaper,but,aboveall,thecrevice,whichwillprovideanentranceforthevermin,hatchedoutside,nearthenarrowpassage。Themaggots’motherhasherownlogic,herprudentforesight。Sheknowshowfeebleherweegrubswillbe,howpowerlesstocuttheirwaythroughanobstacleofanyresistance;andso,despitethetemptationofthesmell,sherefrainsfromlayingsolongasshefindsnoentrancethroughwhichthenewbornwormscanslipunaided。

Iwantedtoknowwhetherthecolor,theshininess,thedegreeofhardnessandotherqualitiesoftheobstaclewouldinfluencethedecisionofamotherobligedtolayhereggsunderexceptionalconditions。Withthisobjectinview,Iemployedsmalljars,eachbaitedwithabitofbutcher’smeat。Therespectivelidsweremadeofdifferentcoloredpaper,ofoilskin,orofsomeofthattinfoil,withitsgoldorcopperysheen,whichisusedforsealingliqueurbottles。Onnotoneofthesecoversdidthemothersstop,withanydesiretodeposittheireggs;but,fromthemomentthattheknifehadmadethenarrowslit,allthelidswere,soonerorlater,visitedandallofthem,soonerorlater,receivedthewhiteshowersomewherenearthegash。Thelookoftheobstacle,therefore,doesnotcount;dullorbrilliant,draborcolored:thesearedetailsofnoimportance;thethingthatmattersisthatthereshouldbeapassagetoallowthegrubstoenter。

Thoughhatchedoutside,atadistancefromthecovetedmorsel,thenewbornwormsarewellabletofindtheirrefectory。Astheyreleasethemselvesfromtheegg,withouthesitation,soaccurateistheirscent,theyslipbeneaththeedgeoftheill—joinedlid,orthroughthepassagecutbytheknife。Beholdthementeringupontheirpromisedland,theirreekingparadise。

Eagertoarrive,dotheydropfromthetopofthewall?Notthey!

Slowlycreeping,theymaketheirwaydownthesideofthejar;theyusetheirforepart,everinquestofinformation,asacrutchandgrapnelinone。Theyreachthemeatandatonceinstallthemselvesuponit。

Letuscontinueourinvestigation,varyingtheconditions。Alargetest—tube,measuringnineincheshigh,isbaitedatthebottomwithalumpofbutcher’smeat。Itisclosedwithwiregauze,whosemeshes,twomillimeterswide,donotpermitofthefly’spassage。

Thebluebottlecomestomyapparatus,guidedbyscentratherthansight。Shehastenstothetesttubewhosecontentsareveiledunderanopaquecoverwiththesamealacrityastotheopentube。

Theinvisibleattractsherquiteasmuchasthevisible。

Shestaysawhileonthelatticeofthemouth,inspectsitattentively;but,whetherbecausecircumstanceshavefailedtoserveme,orbecausethewirenetworkinspiresherwithdistrust,I

neversawherdabhereggsuponitforcertain。Asherevidencewasdoubtful,Ihadrecoursetothefleshfly(Sarcophagacarnaria)。

Thisflyislessfinickyinherpreparations,shehasmorefaithinthestrengthofherworms,whicharebornready—formedandvigorous,andeasilyshowsmewhatIwishtosee。Sheexploresthetrellis—work,choosesameshthroughwhichsheinsertsthetipofherabdomenand,undisturbedbymypresence,emits,oneaftertheother,acertainnumberofgrubs,abouttenorso。True,hervisitswillberepeated,increasingthefamilyatarateofwhichI

amignorant。

Thenewbornworms,thankstoaslightviscidity,clingforamomenttothewiregauze;theyswarm,wriggle,releasethemselvesandleapintothechasm。Itisanineinchdropatleast。Whenthisisdone,themothermakesoff,knowingforacertaintythatheroffspringwillshiftforthemselves。Iftheyfallonthemeat,wellandgood;iftheyfallelsewhere,theycanreachthemorselbycrawling。

Thisconfidenceintheunknownfactoroftheprecipice,withnoindicationbutthatofsmell,deservesfuller,investigation。Fromwhatheightwillthefleshflydaretoletherchildrendrop?I

topthetest—tubewithanothertube,thewidthoftheneckofaclaretbottle。Themouthisclosedeitherwithwiregauze,orwithapapercoverwithaslightcutinit。Altogether,theapparatusmeasurestwenty—fiveinchesinheight。Nomatter:thefallisnotseriousforthelithebacksoftheyounggrubs;and,inafewdays,thetest—tubeisfilledwithlarvae,inwhichitiseasytorecognizethefleshfly’sfamilybythefringedcoronetthatopensandshutsatthemaggot’ssternlikethepetalsofalittleflower。

Ididnotseethemotheroperating:Iwasnotthereatthetime;

butthereisnodoubtpossibleofhercomingnorofthegreatdivetakenbythefamily:thecontentsofthetest—tubefurnishmewithadulyauthenticatedcertificate。

Iadmiretheleapand,toobtainonebetterstill,Ireplacethetubebyanother,sothattheapparatusnowstandsforty—sixincheshigh。Thecolumniserectedataspotfrequentedbyflies,inadimlight。Itsmouth,closedwithawiregauzecover,reachesthelevelofvariousotherappliances,test—tubesandjars,whicharealreadystockedorawaitingtheircolonyofvermin。Whenthepositioniswellknowntotheflies,Iremovetheothertubesandleavethecolumn,lestthevisitorsshouldturnasidetoeasierground。

Fromtimetotime,thebluebottleandthefleshflyperchonthetrellis—work,makeashortinvestigationandthendecamp。

Throughoutthesummerseason,forthreewholemonths,theapparatusremainswhereitis,withouttheleastresult:neveraworm。Whatisthereason?Doesthestenchofthemeatnotspread,comingfromthatdepth?Certainlyitspreads:itisunmistakabletomydullednostrilsandstillmoresotothenostrilsofmychildren,whomI

calltobearwitness。Thenwhydoesthefleshfly,whobutnowwasdroppinghergrubsfromagoodlyheight,refusetoletthemfallfromthetopofacolumntwiceashigh?Doesshefearlestherwormsshouldbebruisedbyanexcessivedrop?Thereisnothingabouthertopointtoanxietyarousedbythelengthoftheshaft。

Ineverseeherexplorethetubeortakeitssize。Shestandsonthetrellisedorifice;andtherethematterends。Canshebeapprisedofthedepthofthechasmbythecomparativefaintnessoftheoffensiveodorsthatarisefromit?Canthesenseofsmellmeasurethedistanceandjudgewhetheritbeacceptableornot?

Perhaps。

Thefactremainsthat,despitetheattractionofthescent,thefleshflydoesnotexposeherwormstodisproportionatefalls。Cansheknowbeforehandthat,whenthechrysalidesbreak,herwingedfamily,knockingwithasuddenflightagainstthesidesofatallchimney,willbeunabletogetout?Thisforesightwouldbeinagreementwiththeruleswhichordermaternalinstinctaccordingtofutureneeds。

Butwhenthefalldoesnotexceedacertaindepth,thebuddingwormsofthefleshflyaredroppedwithoutaqualm,asallourexperimentsshow。Thisprinciplehasapracticalapplicationwhichisnotwithoutitsvalueinmattersofdomesticeconomy。Itisaswellthatthewondersofentomologyshouldsometimesgiveusahintofcommonplaceutility。

Theusualmeatsafeisasortoflargecagewithatopandbottomofwoodandfourwiregauzesides。Hooksfixedintothetopareusedwherebytohangpieceswhichwewishtoprotectfromtheflies。Often,soastoemploythespacetothebestadvantage,thesepiecesaresimplylaidontheflooronthecage。Withthesearrangements,arewesureofwardingofftheflyandhervermin?

Notatall。WemayprotectourselvesagainsttheBluebottle,whoisnotmuchinclinedtolayhereggsatadistancefromthemeat;

butthereisstillthefleshfly,whoismoreventuresomeandgoesmorebrisklytoworkandwhowillslipthegrubsthroughaholeinthemeshesanddroptheminsidethesafe。Agileastheyareandwellabletocrawl,thewormswilleasilyreachanythingonthefloor;theonlythingssecurefromtheirattackswillbethepieceshangingfromtheceiling。Itisnotinthenatureofmaggotstoexploretheheights,especiallyifthisimpliesclimbingdownastringinaddition。

Peoplealsousewiregauzedishcovers。Thetrelliseddomeprotectsthecontentsevenlessthandoesthemeatsafe。Thefleshflytakesnoheedofit。Shecandropherwormsthroughthemeshesonthecoveredjoint。

Thenwhatarewetodo?Nothingcouldbesimpler。Weneedonlywrapthebirdswhichwewishtopreserve——thrushes,partridges,snipeandsoon——inseparatepaperenvelopes;andthesamewithourbeefandmutton。Thisdefensivearmoralone,whileleavingampleroomfortheairtocirculate,makesanyinvasionbythewormsimpossible,evenwithoutacoverorameatsafe:notthatpaperpossessesanyspecialpreservativevirtues,butsolelybecauseitformsanimpenetrablebarrier。TheBluebottlecarefullyrefrainsfromlayinghereggsuponitandthefleshflyfrombringingforthheroffspring,bothofthemknowingthattheirnewbornyoungareincapableofpiercingtheobstacle。

PaperisequallysuccessfulinourstrifeagainsttheMoths,thoseplaguesofourfursandclothes。Tokeepawaythesewholesaleravages,peoplegenerallyusecamphor,naphthalene,tobacco,bunchesoflavenderandotherstrong—scentedremedies。Withoutwishingtomalignthosepreservatives,weareboundtoadmitthatthemeansemployedarenonetooeffective。Thesmelldoesverylittletopreventthehavocofthemoths。

Iwouldthereforecounselourhousewives,insteadofallthischemist’sstuff,tousenewspapersofasuitableshapeandsize。

Takewhateveryouwishtoprotect——yourfurs,yourflanneloryourclothes——andpackeacharticlecarefullyinanewspaper,joiningtheedgeswithadoublefold,wellpinned。Ifthisjoiningisproperlydone,theMothwillnevergetinside。Sincemyadvicehasbeentakenandthismethodemployedinmyhousehold,theolddamagehasneverbeenrepeated。

Toreturntothefly。Apieceofmeatishiddeninajarunderalayeroffine,drysand,afinger’s—breadththick。Thejarhasawidemouthandisleftquiteopen。Letwhoevercomethatwill,attractedbythesmell。TheBluebottlesarenotlongininspectingwhatIhavepreparedforthem:theyenterthejar,gooutandcomebackagain,inquiringintotheinvisiblethingrevealedbyitsfragrance。Adiligentwatchenablesmetoseethemfussingabout,exploringthesandyexpanse,tappingitwiththeirfeet,soundingitwiththeirproboscis。Ileavethevisitorsundisturbedforafortnightorthreeweeks。Noneofthemlaysanyeggs。

Thisisarepetitionofwhatthepaperbag,withitsdeadbird,showedme。Thefliesrefusetolayonthesand,apparentlyforthesamereasons。Thepaperwasconsideredanobstaclewhichthefrailverminwouldnotbeabletoovercome。Withsand,thecaseisworse。Itsgrittinesswouldhurtthenewbornweaklings,itsdrynesswouldabsorbthemoistureindispensabletotheirmovements。

Later,whenpreparingforthemetamorphosis,whentheirstrengthhascometothem,thegrubswilldigtheearthquitewellandbeabletodescend;but,atthestart,thatwouldbeverydangerousforthem。Knowingthesedifficulties,themothers,howevergreatlytemptedbythesmell,abstainfrombreeding。Asamatteroffact,afterlongwaiting,fearinglestsomepacketsofeggsmayhaveescapedmyattention,Iinspectthecontentsofthejarfromtoptobottom。Meatandsandcontainneitherlarvaenorpupae:thewholeisabsolutelydeserted。

Thelayerofsandbeingonlyafinger’s—breadththick,thisexperimentrequirescertainprecautions。Themeatmayexpandalittle,ingoingbad,andprotrudeinoneortwoplaces。Howeversmallthefleshyeyotsthatshowabovethesurface,thefliescometothemandbreed。Sometimesalsothejuicesoozingfromtheputridmeatsoakasmallextentofthesandyfloor。Thatisenoughforthemaggot’sfirstestablishment。Thesecausesoffailureareavoidedwithalayerofsandaboutaninchthick。Thenthebluebottle,thefleshflyandotherflieswhosegrubsbattenondeadbodiesarekeptataproperdistance。

Inthehopeofawakeningustoapropersenseofourinsignificance,pulpitoratorssometimesmakeanunfairuseofthegraveanditsworms。Letusputnofaithintheirdolefulrhetoric。Thechemistryofman’sfinaldissolutioniseloquentenoughofouremptiness:thereisnoneedtoaddimaginaryhorrors。

Thewormofthesepulchreisaninventionofcantankerousminds,incapableofseeingthingsastheyare。Coveredbybutafewinchesofearth,thedeadcansleeptheirquietsleep:noflywillevercometotakeadvantageofthem。

Atthesurfaceofthesoil,exposedtotheair,thehideousinvasionispossible;ay,itistheinvariablerule。Forthemeltingdownandremoldingofmatter,manisnobetter,corpseforcorpse,thanthelowestofthebrutes。Thentheflyexercisesherrightsanddealswithusasshedoeswithanyordinaryanimalrefuse。Naturetreatsuswithmagnificentindifferenceinhergreatregeneratingfactory:placedinhercrucibles,animalsandmen,beggarsandkingsareoneandallalike。Thereyouhavetrueequality,theonlyequalityinthisworldofours:equalityinthepresenceofthemaggot。

CHAPTERXVTHEBLUEBOTTLE:THEGRUB

Thelarvaeofthebluebottlehatchwithintwodaysinthewarmweather。Whetherinsidemyapparatus,indirectcontactwiththepieceofmeat,oroutside,ontheedgeofaslitthatenablesthemtoenter,theysettoworkatonce。Theydonoteat,inthestrictsenseoftheword,thatistosay,theydonotteartheirfood,donotchewitbymeansofimplementsofmastication。Theirmouthpartsdonotlendthemselvestothissortofwork。Thesemouthpartsaretwohornyspikes,slidingoneupontheother,withcurvedendsthatdonotface,thusexcludingthepossibilityofanyfunctionsuchasseizingandgrinding。

Thetwogutturalgrapnelsserveforwalkingmuchratherthanforfeeding。Thewormplantsthemalternatelyintheroadtraversedand,bycontractingitscrupper,advancesjustthatdistance。Itcarriesinitstubularthroattheequivalentofourirontippedstickswhichgivesupportandassistprogress。

Thankstothismachineryofthemouth,themaggotnotonlymovesoverthesurface,butalsoeasilypenetratesthemeat:Iseeitdisappearasthoughitweredippingintobutter。Itcutsitsway,levying,asitgoes,apreliminarytoll,butonlyofliquidmouthfuls。Notthesmallestsolidparticleisdetachedandswallowed。Thatisnotthemaggot’sdiet。Itwantsabroth,asoup,asortoffluidextractofbeefwhichitpreparesitself。Asdigestion,afterall,merelymeansliquefaction,wemaysay,withoutbeingguiltyofparadox,thatthegrubofthebluebottledigestsitsfoodbeforeswallowingit。

Withtheobjectofrelievinggastrictroubles,ourmanufacturingchemistsscrapethestomachsofthepigandsheepandthusobtainpepsin,adigestiveagentwhichpossessesthepropertyofliquefyingalbuminousmattersandleanmeatinparticular。Whycannottheyraspthestomachofthemaggot!Theywouldobtainaproductofthehighestquality,forthecarnivorouswormalsoownsitspepsin,pepsinofasingularlyactivekind,asthefollowingexperimentswillshowus。

Idividethewhiteofahard—boiledeggintotinycubesandplacetheminalittletest—tube。Onthetopofthecontents,Isprinkletheeggsofthebluebottle,eggsfreefromtheleaststain,takenfromthoselaidontheoutsideoftinsbaitedwithmeatandnotabsolutelyshut。Asimilartest—tubeisfilledwithwhiteofegg,butreceivesnogerms。Bothareclosedwithaplugofcotton—woolandleftinadarkcorner。

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