Inafewdays,thetubeswarmingwithnewbornvermincontainsaliquidasfluidandtransparentaswater。NotadropwouldremaininthetubeifIturneditupsidedown。Allthewhiteofegghasdisappeared,liquefied。Asfortheworms,whicharealreadyafairsize,theyseemveryillatease。Deprivedofasupportwhencetoattaintheouterair,mostofthemdiveintothebrothoftheirownmaking,wheretheyperishbydrowning。Others,endowedwithgreatervigor,crawluptheglasstotheplugandmanagetomaketheirwaythroughthewadding。Theirpointedfront,armedwithgrapplingirons,isthenailthatpenetratesthefibrousmass。
Intheothertest—tube,standingbesidethefirstandsubjectedtothesameatmosphericinfluences,nothingstrikinghasoccurred。
Thehard—boiledwhiteofegghasretaineditsdeadwhitecoloranditsfirmness。IfinditasIleftit。TheutmostthatIobserveisafewtracesofmust。Theresultofthisfirstexperimentispatent:theBluebottle’sgrubisthemediumthatconvertscoagulatedalbumenintoaliquid。
Thevalueofchemist’spepsinisestimatedbythequantityofhard—
boiledwhiteofeggwhichagramofthatagentcanliquefy。Themixturehastobeexposedinanoventoatemperatureof1400F。
andalsotobefrequentlyshaken。Mypreparation,inwhichthebluebottle’seggsarehatched,isneithershakennorsubjectedtotheheatofanoven;everythinghappensinquietnessandunderthethermometricconditionsofthesurroundingair;nevertheless,inafewdays,thecoagulatedalbumen,treatedbythevermin,runslikewater。
Thereagentthatcausesthisliquefactionescapesmyendeavorstodetectit。Thewormsmustdisgorgeitininfinitesimaldoses,whilethespikesintheirthroats,whichareincontinualmovement,emergealittlewayfromthemouth,reenterandreappear。Thosepistonthrusts,thosequasi—kisses,areaccompaniedbytheemissionofthesolvent:atleast,thatishowIpictureit。Themaggotspitsonitsfood,placesonitthewherewithaltomakeitintobroth。Toappraisethequantityofthematterexpectoratedisbeyondmypowers:Iobservetheresult,butdonotperceivetheleaveningagent。
Well,thisresultisreallyastounding,whenweconsiderthescantinessofthemeans。Nopig’sorsheep’spepsincanrivalthatoftheworm。IhaveabottleofpepsinthatcomesfromtheSchoolofChemistryatMontpellier。Ilavishlypowdersomepiecesofhard—boiledwhiteofeggwiththepotentdrug,justasIdidwiththeeggsoftheBluebottle。Theovenisnotbroughtintoplay,neitherisdistilledwateradded,norhydrochloricacid:twoauxiliarieswhicharerecommended。Theexperimentisconductedinexactlythesamewayasthatofthetubeswiththevermin。TheresultisentirelydifferentfromwhatIexpected。Thewhiteofeggdoesnotliquefy。Itsimplybecomesmoistonthesurface;andeventhismoisturemaycomefromthepepsin,whichishighlyabsorbent。Yes,Iwasright:ifthethingwerefeasible,itwouldbeanadvantageforthechemiststocollecttheirdigestivedrugfromthestomachofthemaggot。Theworm,inthiscase,beatsthepigandthesheep。
Thesamemethodisfollowedfortheremainingexperiments。Iputthebluebottle’seggstohatchonapieceofmeatandleavethewormstodotheirworkastheyplease。Theleantissues,whetherofmutton,beeforpork,nomatterwhich,arenotturnedintoliquid;theybecomeapeasoupofaclaretybrown。Theliver,thelung,thespleenareattackedtobetterpurpose,without,however,gettingbeyondthestateofasemi—fluidjam,whicheasilymixeswithwaterandevenappearstodissolveinit。Thebrainsdonotliquefyeither:theysimplymeltintoathingruel。
Ontheotherhand,fattysubstances,suchasbeefsuet,lardandbutter,donotundergoanyappreciablechange。Moreover,thewormssoondwindleaway,incapableofgrowing。Thissortoffooddoesnotsuitthem。Why?Apparentlybecauseitcannotbeliquefiedbythereagentdisgorgedbytheworms。Inthesameway,ordinarypepsindoesnotattackfattysubstances;ittakespancreatintoreducethemtoanemulsion。Thiscuriousanalogyofproperties,positiveforalbuminous,negativeforfattymatter,proclaimsthesimilarityandperhapstheidentityofthedissolventdischargedbythegrubsandthepepsinofthehigheranimals。
Hereisanotherproof:theusualpepsindoesnotdissolvetheepidermis,whichisamaterialofahornynature。Thatofthemaggotsdoesnotdissolveiteither。IcaneasilyrearbluebottlegrubsondeadcricketswhosebelliesIhavefirstopened;butIdonotsucceedifthemorselbeleftintact:thewormsareunabletoperforatethesucculentpaunch;theyarestoppedbythecuticle,onwhichtheirreagentrefusestoact。OrelseIgivethemfrogs’
hindlegs,strippedoftheirskin。Thefleshturnstobrothanddisappearstothebone。IfIdonotpeelthelegs,theyremainintactinthemidstofthevermin。Theirthinskinissufficienttoprotectthem。
Thisfailuretoactupontheepidermisexplainswhythebluebottleatworkontheanimaldeclinestolayhereggsonthefirstpartthatcomeshandy。Sheneedsthedelicatemembraneofthenostrils,eyesorthroat,orelsesomewoundinwhichthefleshislaidbare。
Nootherplacesuitsher,howeverexcellentforflavoranddarkness。Atmost,findingnothingbetterwhenmystratagemsinterfere,shepersuadesherselftodabafeweggsundertheaxillaofapluckedbirdorinthegroin,twopointsatwhichtheskinisthinnerthanelsewhere。
Withhermaternalforesight,thebluebottleknowstoperfectionthechoicesurfaces,theonlyonesliabletosoftenandrunundertheinfluenceofthereagentdribbledbythenewborngrubs。Thechemistryofthefutureisfamiliartoher,thoughshedoesnotuseitforherownfeeding;motherhood,thatgreatinspirerofinstinct,teachesherallaboutit。
Scrupulousthoughshebeinchoosingexactlywheretolayhereggs,thebluebottledoesnottroubleaboutthequalityoftheprovisionsintendedforherfamily’sconsumption。Anydeadbodysuitsherpurpose。Redi,theItalianscientistwhofirstexplodedtheold,foolishnotionofwormsbegottenofcorruption,fedthevermininhislaboratorywithmeatofverydifferentkinds。Inordertomakehisteststhemoreconclusive,heexaggeratedthelargessofthedininghall。Thedietwasvariedwithtigerandlionflesh,bearandleopard,foxandwolf,muttonandbeef,horseflesh,donkeyfleshandmanyothers,suppliedbytherichmenagerieofFlorence。
Thiswastefulnesswasunnecessary:wolfandmuttonareallthesametoanunprejudicedstomach。
Adistantdiscipleofthemaggot’sbiographer,IlookattheprobleminalightwhichRedineverdreamtof。Anyfleshofoneofthehigheranimalssuitsthefly’sfamily。Willitbethesameifthefoodsuppliedbeofalowerorganismandconsistoffish,forinstance,offrog,mollusk,insect,centipede?Willthewormsaccepttheseviandsand,aboveall,cantheymanagetoliquefythem,whichisthefirstandforemostcondition?
Iserveapieceofrawwhiting。Thefleshiswhite,delicate,partlytranslucent,easyforourstomachstodigestandnolesssuitedtothegrub’sdissolvent。Itturnsintoanopalescentfluid,whichrunslikewater。Infact,itliquefiesinmuchthesamewayashard—boiledwhiteofegg。Thewormsatfirstwaxfat,aslongastheconditionsallowofsomesolideyotsremaining;
then,whenfootholdfails,threatenedwithdrowninginthetoofluidbroth,theycreepupthesideoftheglass,anxiousandrestlesstobeoff。Theyclimbtothecotton—woolstopperofthetest—tubeandtrytoboltthroughthewadding。Endowedwithstubbornperseverance,nearlyallofthemdecampinspiteoftheobstacle。Thetest—tubewiththewhiteofeggshowedmeasimilarexodus。Althoughthefaresuitsthem,astheirgrowthwitnesses,thewormsceasefeedingandmakeapointofescapingwhendeathbydrowningisimminent。
Withotherfish,suchasskateandsardines,withthefleshoffrogsandtreefrogs,themeatsimplydissolvesintoaporridge。
Hashesofslug,Scolopendraorprayingmantisfurnishthesameresult。
Inallthesepreparations,thedissolvingagentofthewormsisasmuchinevidenceaswhenbutcher’smeatisemployed。Moreover,thegrubsseemsatisfiedwiththequeerdishwhichmycuriosityprescribesforthem;theythriveamidstthevictualsandundergotheirtransformationintopupae。
Theconclusion,therefore,ismuchmoregeneralthanRediimagined。
Anymeat,nomatterwhetherofahigherorlowerorder,suitsthebluebottleforthesettlementofherfamily。Thecarcassesoffurredandfeatheredanimalsarethefavoritevictuals,probablybecauseoftheirrichness,whichallowsofplentifullayings;but,shouldtheoccasiondemandit,theothersarealsoaccepted,withoutinconvenience。Anycarrionthathaslivedthelifeofananimalcomeswithinthedomainofthesescavengers。
Whatistheirnumbertoonemother?Ihavealreadyspokenofadepositofthreehundred,countedeggbyegg。Aquitefortuitouscircumstanceenabledmetogomuchfarther。InthefirstweekofJanuary1905,weexperiencedasuddenshortcoldsnapofaseverityveryexceptionalinmypartofthecountry。Thethermometerfelltotwelvedegreesbelowzero。Whileafiercenorthwindwasragingandbeginningtoreddentheleavesoftheolivetrees,cameoneandbroughtmeabarnorscreechowl,whichhehadfoundontheground,exposedtotheair,notfarfrommyhouse。MyreputationasaloverofanimalsmadethedonorbelievethatIshouldbepleasedwithhisgift。
Iwas,asamatteroffact,butforreasonswhereofthefindercertainlyneverdreamt。Theowlwasuntouched,withtrimfeathersandnottheleastwoundthatshowed。Perhapshehaddiedofcold。
Whatmademegratefullyacceptthepresentwasexactlythatwhichwouldhaveinclinedanyonebutmyselftorefuseit。Theowl’seyes,glazedindeath,werehiddenunderathickmassofeggs,whichIrecognizedasabluebottle’s。Similarmassesoccupiedthevicinityofthenostrils。IfIwantedmaggots,here,ofacertainty,wasarichercropthanIhadeverbeheld。
Iplacethecorpseonthesandofapan,withawiregauzecover,andleaveeventstotaketheircourse。ThelaboratoryinwhichI
installmybirdisnoneotherthanmystudy。Itisascoldinthere,ornearly,asoutside,somuchsothatthewaterintheaquariuminwhichIusedtorearcaddiswormshasfrozenintoasolidblockofice。Undertheseconditionsoftemperature,theowl’seyeskeeptheirwhiteveilofgermsunchanged。Nothingstirs,nothingswarms。Wearyofwaiting,Ipaynomoreattentiontothecarcass;Ileavethefuturetodecidewhetherthecoldhasexterminatedthefly’sfamilyornot。
BeforetheendofMarch,thepacketsofeggshavedisappeared,I
knownothowlong。Thebird,forthatmatter,seemstobeintact。
Ontheventralsurface,whichisturnedtotheair,thefeatherskeeptheirsmootharrangementandtheirfreshcoloring。Iliftthething。Itislight,verydryandgivesahardsound,likeanoldshoetannedbythesummersuninthefields。Thereisnosmell。
Thedrynesshasvanquishedthestench,which,inanycase,wasneveroffensiveduringthattimeoffrost。Ontheotherhand,theback,whichtouchedthesand,isaloathsomewreck,partlydeprivedofitsfeathers。Thequillsofthetailarebarebarreled;afewwhitenedbonesshow,deprivedoftheirmuscles。Theskinhasturnedintoadarkleather,piercedwithroundholeslikethoseofasieve。Itisallhideouslyugly,butmostinstructive。
Thewretchedowl,withhisshatteredbackbone,teachesus,firstofall,thatatemperaturetwelvedegreesoffrostdoesnotendangertheexistenceofthebluebottle’sgerms。Thewormswerebornwithoutaccident,despitetherudeblast;theyfeastedcopiouslyonextractofmeat;then,growingbigandfat,theydescendedintotheearthbypiercingroundholesinthebird’sskin。Theirpupaemustnowbeinthesandofthepan。
Theyare,inpointoffact,andinsuchnumbersthatIhavetoresorttosiftinginordertocollectthem。IfIusedtheforceps,Ishouldneverhavedonesortingsogreataquantity。Thesandpassesthroughthemeshesofthesieve,thepupaeremainabove。Tocountthemwouldwearoutmypatience。Imeasurethembythebushel,thatistosay,withathimbleofwhichIknowtheholdingcapacityinpupae。Theresultofmycalculationisnotfarshortofninehundred。
Doesthisfamilyproceedfromonemother?Iamquitereadytoadmitit,sounlikelyisitthatthebluebottle,whoissorareinsideourhousesduringtheseverecoldofwinter,shouldbefrequentenoughoutsidetoformintogroupsandtodobusinessincommonwhileanicyblastisraging。Abelatedspecimen,theplaythingofthenorthwind,andonealonemusthavedepositedtheburdenofherovariesontheowl’seyes。Thislayingofninehundredeggs,anincompletelayingperhaps,bearswitnesstothemightypartplayedbytheflyasaliquidatorofcorpses。
Beforethrowingawaythescreechowltreatedbytheworms,letusovercomeourrepugnanceandgiveaglanceinsidethebird。Weseeatortuouscavity,fencedinbynamelessruins。Musclesandbowelshavedisappeared,convertedintobrothandgraduallyconsumedbytheteemingthrong。Ineverypart,whatwaswethasbecomedry,whatwassolidmuddy。Invainmyforcepsransackseverynookandcorner:itdoesnothituponasinglepupa。Allthewormshaveemigrated,all,withoutexception。Fromfirsttolast,theyhaveforsakentherefugeofthecorpse,sosofttotheirdelicateskins;
theyhaveleftthevelvetforthehardground。Isdrynessnecessarytothematthisstage?Theyhaditinthecarcass,whichwasthoroughlydrained。Wouldtheyprotectthemselvesagainstthecoldandrain?Nosheltercouldsuitthembetterthanthethickquiltofthefeathers,whichhasremainedwhollyundamagedonthebelly,thebreastandeverypartthatwasnotintouchwiththeground。Itlooksasthoughtheyhadfledfromcomforttoseekalesskindlydwellingplace。Whenthehouroftransformationcame,alllefttheowl,thatmostexcellentlodging;alldivedintothesand。
Theexodusfromthemortuarytabernaclewasmadethroughtheroundholeswherewiththeskinispierced。Thoseholesaretheworms’
work:ofthatthereisnodoubt;andyetwehavelatelyseenthemothersrefuseasabedfortheireggsanypartwhereatthefleshisprotectedbyaskinofsomethickness。Thereasonisthefailureofthepepsintoactonepidermicsubstances。Intheabsenceofliquefactionatsuchpoints,thenourishinggruelisunprocurable。Ontheotherhand,thetinywormsarenotable——oratleastdonotknowhow——todigthroughtheintegumentwiththeirpairofgutturalharpoons,torenditandreachtheliquefiableflesh。Thenewbornlackstrengthand,aboveall,purpose。But,asthetimecomesfordescendingintotheearth,theworms,nowpowerfulandsuddenlyversedinthenecessaryart,wellknowhowtoeatawaypatientlyandclearthemselvesapassage。Withthehooksoftheirspikestheydig,scratchandtear。Instincthasflashesofinspiration。Whattheanimaldidnotknowhowtodoatthestartitlearnswithoutapprenticeshipwhenthetimecomestopracticethisorthatindustry。Themaggotripeforburialperforatesamembranousobstaclewhichthegrubintentuponitsbrothwouldnotevenhaveattemptedtoattackwitheitheritspepsinoritsgrapnels。
Whydoesthewormquitthecarcass,thatcapitalshelter?Whydoesitgoandtakeupitsabodeintheground?Astheleadingdisinfectorofdeadthings,itworksatthemostimportantmatter,thesuppressionoftheinfection;butitleavesaplentifulresiduum,whichdoesnotyieldtothereagentsofitsanalyticalchemistry。Theseremainshavetodisappearintheirturn。Afterthefly,anatomistscomehastening,whotakeupthedryrelic,nibbleskin,tendonsandligamentsandscrapethebonesclean。
ThegreatestexpertinthisworkistheDermestesbeetle,anenthusiasticgnawerofanimalremains。Soonerorlater,hewillcometothejointalreadyexploitedbythefly。Nowwhatwouldhappenifthepupaewerethere?Theanswerisobvious。TheDermestes,wholoveshardfood,woulddighisteethintothehornylittlekegsanddemolishthematabite。Eventhoughhedidnottouchthecontents,alivethingwhichheprobablydislikes,hewouldatleasttesttheflavorofthatlifelesssubstance,thecontainer。ThefutureFlywouldbelost,becausehercasingwouldbepierced。Evenso,inthestoreroomsofoursilkmills,acertainDermestes(Dermestesvulpinus,FABR。)digsintothecocoonstoattackthehornycoveringofthechrysalis。
Themaggotforeseesthedangerandmakesitselfscarcebeforetheotherarrives。Inwhatsortofmemorydoesithousesomuchwisdom,indigent,headlesscreaturethatitis,foritisonlybyextensionthatwecangivethenameofheadtotheanimal’spointedforepart?Howdiditlearnthat,tosafeguardthepupa,itmustdesertthecarcassandthat,tosafeguardthefly,itmustnotburyitselftoofardown?
Toemergefromundergroundaftertheperfectinsectishatched,thebluebottle’sdeviceconsistsindisjointingherheadintotwomovablehalves,which,eachdistendedwithitsgreatredeye,byturnsseparateandreunite。Intheinterveningspace,alarge,glassyherniarisesanddisappears,disappearsandrises。Whenthetwomoveasunder,withoneeyeforcedbacktotheright,theothertotheleft,itisasthoughtheinsectweresplittingitsbrainpaninordertoexpelthecontents。Thentheherniarises,bluntattheendandswollenintoagreatknob。Next,theforeheadclosesandtheherniaretreats,leavingvisibleonlyakindofshapelessmuzzle。Inshort,afrontalpouch,withdeeppulsationsmomentarilyrenewed,becomestheinstrumentofdeliverance,thepestlewherewiththenewlyhatchedbluebottlebruisesthesandandcausesittocrumble。Graduallythelegspushtherubbishbackandtheinsectadvancessomuchtowardthesurface。
Ahardtask,thisexhumationbydintoftheblowsofacleftandpalpitatinghead。Moreover,theexhaustingefforthastobemadeatthemomentofgreatestweakness,whentheinsectleavesthatprotectingcasket,itspupa。Itemergesfromitpale,flabbyandunsightly,sorrilycladinthewingswhich,foldedlengthwiseandmadeshorterbytheirscallopededge,onlyjustcoverthetopoftheback。Wildlybristlingwithhairsandcoloredashen—gray,itisapiteoussight。Thelargesetofwings,suitableforflight,willspreadlater。Forthemoment,itwouldonlybeinthewayamidtheobstaclestobepassedthrough。Lateralsowillcomethefaultlessdresswhereintheiridescentindigo—bluestandsoutagainsttheseverityoftheblack。
Thefrontalherniathatcrumblesthesandwithitsimpacthasatendencytomakeplayforsometimeaftertheemergencefromtheground。Takeholdwiththeforcepsofoneofthehindlegsofanewlyreleasedfly。Forthwith,theimplementoftheheadbeginstowork,swellingandsubsidingasenergeticallyasamomentago,whenithadtomakeaholeinthesand。Theinsect,hamperedinitsmovementsaswhenitwasunderground,strugglesasbestitcanagainsttheonlyobstaclethatitknows。Withitsheavingknob,itpoundstheairevenasbutnowitpoundedtheearthybarrier。Inallunpleasantcircumstances,itsoneresourceistocleaveitsheadandproduceitscranialhernia,whichmovesoutandin,inandout。Fornearlytwohours,interspersedwithhaltsduetofatigue,thelittlemachinekeepsthrobbinginmyforceps。
Inthemeantime,however,thedesperateoneishardeningherskin;
shespreadswidethesailofherwingsanddonsherdeepmourningofblackanddarkestblue。Thenhereyes,warpedsideways,cometogetherandresumetheirnormalposition。Thecleftforeheadcloses;thedeliveringblistergoesin,nevertoshowitselfagain。
Butthereisoneprecautiontobetakenfirst。Withitsfronttarsi,theinsectcarefullybrushesthebumpabouttodisappearfromview,lestgritshouldlodgeinthecraniumwhenthetwohalvesoftheheadarejoinedforgood。
Themaggotisawareofthetrialsthatawaititwhen,asafly,itwillhavetocomeupfromunderground;itknowsbeforehandhowdifficulttheascentwillbewiththefeebleinstrumentatitsdisposal,sodifficult,infact,astobecomefatalshouldthejourneybeatallprolonged。Itforeseesthedangersaheadofitandavertsthemaswellasitcan。Giftedwithtwoironshodsticksinitsthroat,itcaneasilydescendtosuchdepthsasitpleases。Theneedforgreaterquietandalesstryingtemperaturecallsforthedeepestpossiblehome:thelowerdownitis,thebetterforthewelfareofthewormandthepupa,onconditionthatdescentbepracticable。Itis,perfectly;andyet,thoughfreetoobeyitsinspiration,thegrubrefrains。Irearitinadeeppan,fulloffine,drysand,easytoexcavate。Theintermentnevergoesveryfar。Aboutahand’sbreadthisallthatthemostprogressivediggerventuresupon。Mostoftheinterredremainnearerstilltothesurface。Here,underathinlayerofsand,thegrub’sskinhardensandbecomesacoffin,acasket,whereinthetransformationsleepisslept。Afewweekslater,theburiedoneawakes,transfiguredbutweak,havingnaughtwherewithtounearthherselfbutthethrobbingherniaofheropenforehead。
Whatthemaggotdeniesitselfitisopentometorealize,shouldI
caretoknowthedepthwhencetheflyisabletomount。Iplacefifteenbluebottlepupae,obtainedinwinter,atthebottomofawidetubeclosedatoneend。Abovethepupaeisaperpendicularcolumnoffine,drysand,theheightofwhichvariesindifferenttubes。Aprilcomesandthehatchingbegins。
Atubewithsixcentimetersofsand,theshallowestofthecolumnsunderexperiment,yieldsthebestresult。Ofthefifteensubjectsinterredinthepupastage,fourteeneasilyreachthesurfacewhentheybecomeflies。Onlyoneofthemperishes,onewhohasnotevenattemptedtheascent。Withtwelvecentimetersofsand,fouremerge。Withtwentycentimeters,two,nomore。Theotherflies,jadedwiththeirexertions,havediedatahigherorlowerstageoftheroad。Lastly,withyetanothertubewhereinthecolumnofsandmeasuredsixtycentimeters,Iobtainedtheliberationofonlyasinglefly。Thepluckycreaturemusthavehadahardstruggletomountfromsogreatadepth,fortheotherfourteendidnotevenmanagetoburstthelidoftheircaskets。
Ipresumethattheloosenessofthesandandtheconsequentpressureineverydirection,similartothatexercisedbyfluids,haveacertainbearingonthedifficultiesoftheexhumation。Twomoretubesareprepared,butthistimesuppliedwithfreshmould,lightlyheapedup,whichhasnottheincoherenceofsand,withtheattendantdrawbackofpressure。Sixcentimetersofmouldgivemeeightfliesforfifteenpupaeburied;twentycentimetersgivemeonlyone。Thereislesssuccessthanwiththesandycolumn。Mydevicehasdiminishedthepressure,but,atthesametime,increasedthepassiveresistance。Thesandfallsofitselfundertheimpactofthefrontalrammer;theunyieldingmoulddemandsthecuttingofagallery。Infact,Iperceive,ontheroadfollowed,ashaftwhichcontinuesindefinitelysuchasitis。Theflyhasboreditwiththetemporaryblisterthatthrobsbetweenhereyes。
Ineverymedium,therefore,whethersand,mouldoranyearthycombination,greatarethesufferingsthatattendtheexhumationofthefly。Andsothemaggotshunsthedepthswhichadesireforadditionalsecuritymightseemtorecommend。Thewormhasitsownprudence:foreseeingthedangersahead,itrefrainsfrommakinggreatdescentsthatmightpromotethewelfareofthemoment。Itneglectsthepresentforthesakeofthefuture。
CHAPTERXVIAPARASITEOFTHEMAGGOT
Thedangersoftheexhumationarenottheonlyones;theBluebottlemustbeacquaintedwithothers。Life,whenallissaid,isaknacker’syardwhereinthedevoureroftodaybecomesthedevouredoftomorrow;andtherobberofthedeadcannotfailtoberobbedofherownlifewhenthetimecomes。IknowthatshehasoneexterminatorinthepersonofthetinySaprinusbeetle,afisheroffatsausagesontheedgeofthepoolsformedbyliquescentcorpses。
Hereswarmincommonthegrubsofthegreenbottle,thefleshflyandthebluebottle。TheSaprinusdrawsthemtohimfromthebankandgobblesthemindiscriminately。Theyrepresenttohimmorselsofequalvalue。
Thisbanquetcanbeobservedonlyintheopencountry,undertheraysofahotsun。Sapriniandgreenbottlesneverenterourhouses;thefleshflyvisitsusbutdiscreetly,doesnotfeelathomewithus;theonlyonewhocomesfussingalongisthebluebottle,whothusescapesthetributeduetotheconsumerofplumpsausages。But,inthefields,whereshereadilylayshereggsuponanycarcassthatshefinds,she,aswellastheothers,seesherverminsweptawaybythegluttonousSaprinus。
Inaddition,graverdisastersdecimateherfamily,if,asIdonotdoubt,wecanapplytothebluebottlewhatIhaveseenhappeninthecaseofherrival,thefleshfly。Sofar,IhavehadnoopportunityofactuallyperceivingwiththefirstwhatIhavetotellofthesecond;still,Idonothesitatetorepeatabouttheonewhatobservationhastaughtmeabouttheother,forthelarvalanalogiesbetweenthetwofliesareveryclose。
Herearethefacts。Ihavegatheredanumberofpupaeofthefleshflyinoneofmyverminjars。Wishingtoexaminethepupa’shinderend,whichishollowedintoacupandscallopedintoacoronet,I
staveinoneofthelittlebarrelsandforceopenthelastsegmentswiththepointofmypocketknife。ThehornykegdoesnotcontainwhatIexpectedtofind:itisfulloftinygrubspackedoneatoptheotherwiththesameeconomyofspaceasanchoviesinabottle。
Savefortheskin,whichhashardenedintoabrownshell,thesubstanceofthemaggothasdisappeared,changedintoarestlessswarm。
Therearethirty—fiveoccupants。Ireplacethemintheircasket。
Therestofmyharvest,wherein,nodoubt,areotherpupaesimilarlystocked,isarrangedintubesthatwilleasilyshowmewhathappens。Thethingtodiscoveriswhatgenusofparasitesthegrubsenclosedbelongto。Butitisnotdifficult,withoutwaitingforthehatchingoftheadults,torecognizetheirnaturemerelybytheirmodeoflife。TheyformpartofthefamilyofChalcididae,whoaremicroscopicravagersoflivingentrails。
Notlongago,inwinter,Itookfromthechrysalisofagreatpeacockmothfourhundredandforty—nineparasitesbelongingtothesamegroup。Thewholesubstanceofthefuturemothhaddisappeared,allbutthenymphalwrapper,whichwasintactandformedahandsomeRussia—leatherwallet。Thewormgrubswerehereheapedupandsqueezedtogethertothepointofstickingtooneanother。Thehairpencilextractstheminbundlesandcannotseparatethemwithoutsomedifficulty。Theholdingcapacityisstrainedtotheutmost;thesubstanceofthevanishedMothwouldnotfillitbetter。Thatwhichdiedhasbeenreplacedbyalivingmassofequaldimensions,butsubdivided。Thepriceofthiscolony’sexistenceistheconversionofthechrysalisintoasortofmilkfoodofdoubtfulconstitution。Theenormousudderhasbeendrainedoutright。
Youshudderwhenyouthinkofthatbuddingfleshnibbledbitbybitbyfourorfivehundredgormandizers;thehorrifiedimaginationrefusestopicturetheanguishsufferedbythetorturedwretch。
Butistherereallyanypain?Wehaveleavetodoubtit。Painisapatentofnobility;itismorepronouncedinproportionasthesuffererbelongstoahigherorder。Inthelowerranksofanimallife,itmustbegreatlyreduced,perhapsevennil,especiallywhenlife,inthethroesofevolution,hasnotyetacquiredastableequilibrium。Thewhiteofaneggislivingmatter,butendurestheprickofaneedlewithoutaquiver。Woulditnotbethesamewiththechrysalisofthegreatpeacock,dissectedcellbycellbyhundredsofinfinitesimalanatomists?Woulditnotbethesamewiththepupaofthefleshfly?Theseareorganismsputbackintothecrucible,revertingtotheeggstateforasecondbirth。Thereisreasontobelieve,therefore,thattheirdestructioncrumbbycrumbismerciful。
TowardstheendofAugust,theparasiteofthefleshfly’sgrubsmakesherappearanceoutofdoorsintheadultform。SheisaChalcidid,asIexpected。Sheissuesfromthebarrelthroughoneortwolittleroundholeswhichtheprisonershavepiercedwithapatienttooth。Icountsomethirtytoeachpupa。Therewouldnotbeenoughroomintheabodeifthefamilywerelarger。
Theimpisaslimandelegantcreature,butoh,howsmall!Shemeasureshardlytwomillimeters。Hergarbisbronzedblack,withpalelegsandaheartshaped,pointed,slightlypedunculateabdomen,withneveratraceofaprobeforinoculatingtheeggs。
Theheadistransversal,thewidthexceedingthelength。
Themaleisonlyhalfthesizeofthefemale;heisalsoverymuchlessnumerous。Perhapspairingishere,asweseeelsewhere,asecondarymatterfromwhichitispossibletoabstain,inpart,withoutinjuringtheprospectsoftherace。Nevertheless,inthetubewhereinIhavehousedtheswarm,thefewmaleslostamongthecrowdardentlywoothepassingfair。Thereismuchtobedoneoutside,aslongasthefleshfly’sseasonlasts;thingsareurgent;andeachpigmyhurriesasfastasshecantotakeupherpartasanexterminator。
Howistheparasite’sinroadintothefleshfly’spupaeeffected?
Truthisalwaysveiledinacertainmystery。Thegoodfortunethatsecuredmetheravagedpupataughtmenothingconcerningthetacticsoftheravager。IhaveneverseentheChalcididexplorethecontentsofmyappliances;myattentionwasengagedelsewhereandnothingissodifficulttoseeasathingnotyetsuspected。
But,thoughdirectobservationbelacking,logicwilltellusapproximatelywhatwewanttoknow。
Itisevident,tobeginwith,thattheinvasioncannothavebeenmadethroughthesturdyamourofthepupae。Thisistoohardtobepenetratedbythemeansatthepigmy’sdisposal。Naughtbutthedelicateskinofthemaggotslendsitselftotheintroductionofthegerms。Anegglayingmother,therefore,appears,inspectsthesurfaceofthepoolofsaniesswarmingwithgrubs,selectstheonethatsuitsherandperchesonit;then,withthetipofherpointedabdomen,whenceemerges,foraninstant,ashortprobekepthiddenuntilthen,sheoperatesonthepatient,perforatinghispaunchwithadexterouswoundintowhichthegermsareinserted。
Probably,anumberofpricksareadministered,asthepresenceofthirtyparasitesseemstodemand。
Anyway,themaggot’sskinispiercedateitheronepointormany;
andthishappenswhilethegrubisswimminginthepoolsformedbytheputridflesh。Havingsaidthis,wearefacedwithaquestionofseriousinterest。Tosetitforthnecessitatesadigressionwhichseemstohavenothingtodowiththesubjectinhandandisneverthelessconnectedwithitintheclosestfashion。Withoutcertainpreliminaries,theremainderwouldbeunintelligible。Sonowforthepreliminaries。
IwasinthosedaysbusywiththepoisonoftheLanguedocianscorpionanditsactionuponinsects。Todirectthestingtowardthisortheotherpartofthevictimandmoreovertoregulateitsemissionwouldbeabsolutelyimpossibleandalsoverydangerous,aslongasthescorpionswereallowedtoactastheypleased。I
wishedtobeablemyselftochoosetheparttobewounded;I
likewisewishedtovarythedoseofpoisonatwill。Howtosetaboutit?Thescorpionhasnojarlikereceptacleinwhichthevenomisaccumulatedandstored,likethatpossessed,forinstance,bythewaspandthebee。Thelastsegmentofthetail,gourdshapedandsurmountedbythesting,containsonlyapowerfulmassofmusclesalongwhichliethedelicatevesselsthatsecretethepoison。