新概念英語第四冊課文

新觀點英語第四冊課文Word格式的文本，已排版。Wecanreadofthingsthathappened5,000yearsagointheNearEast,wherepeoplefirstlearnedtowrite.Buttherearesomepartsoftheworldwhereevennowpeoplecannotwrite.Theonlywaythattheycanpreservetheirhistoryistorecountitassagas--legendshandeddownfromonegenerationofstory-tellerstoanother.Theselegendsareusefulbecausetheycantellussomethingaboutmigrationsofpeoplewholivedlongago,butnonecouldwritedownwhattheydid.AnthropologistswonderedwheretheremoteancestorsofthePolynesianpeoplesnowlivinginthePacificIslandscamefrom.ThesagasofthesepeopleexplainthatsomeofthemcamefromIndonesiaabout2,000yearsago.Butthefirstpeoplewhowerelikeourselveslivedsolongagothateventheirsagas,iftheyhadany,areforgotten.Soarchaeologistshaveneitherhistorynorlegendstohelpthemtofindoutwherethefirst'modernmen'camefrom.Fortunately,however,ancientmenmadetoolsofstone,especiallyflint,becausethisiseasiertoshapethanotherkinds.Theymayalsohaveusedwoodandskins,butthesehaverottedaway.Stonedoesnotdecay,andsothetoolsoflongagohaveremainedwheneventhebonesofthemenwhomadethemhavedisappearedwithouttrace.Why,youmaywonder,shouldspidersbeourfriends?Becausetheydestroysomanyinsects,andinsectsincludesomeofthegreatestenemiesofthehumanrace.Insectswouldmakeitimpossibleforustoliveintheworld;theywoulddevourallourcropsandkillourflocksandherds,ifitwerenotfortheprotectionwegetfrominsect-eatinganimals.Weowealottothebirdsandbeastswhoeatinsectsbutallofthemputtogetherkillonlyafractionofthenumberdestroyedbyspiders.Moreover,unlikesomeoftheotherinsecteaters,spidersneverdotheleastharmtousorourbelongings.Spidersarenotinsects,asmanypeoplethink,norevennearlyrelatedtothem.Onecantellthedifferencealmostataglanceforaspideralwayshaseightlegsandaninsectnevermorethansix.Howmanyspidersareengagedinthisworkonourbehalf?OneauthorityonspidersmadeacensusofthespidersinagrassfieldinthesouthofEngland,andheestimatedthatthereweremorethan2,250,000inoneacre,thatissomethinglike6,000,000spidersofdifferentkindsonafootballpitch.Spidersarebusyforatleasthalftheyearinkillinginsects.Itisimpossibletomakemorethanthewildestguessathowmanytheykill,buttheyarehungrycreatures,notcontentwithonlythreemealsaday.IthasbeenestimatedthattheweightofalltheinsectsdestroyedbyspidersinBritaininoneyearwouldbegreaterthanthetotalWord格式的文本，已排版。weightofallthehumanbeingsinthecountry.T.H.*IESparethatSpiderfromTheListenerModernalpiniststrytoclimbmountainsbyaroutewhichwillgivethemgoodsport,andthemoredifficultitis,themorehighlyitisregarded.Inthepioneeringdays,however,thiswasnotthecaseatall.Theearlyclimberswerelookingfortheeasiestwaytothetopbecausethesummitwastheprizetheysought,especiallyifithadneverbeenattainedbefore.Itistruethatduringtheirexplorationstheyoftenfaceddifficultiesanddangersofthemostperilousnature,equippedinamannerwhichwouldmakeamodernclimbershudderatthethought,buttheydidnotgooutoftheirwaytocourtsuchexcitement.Theyhadasingleaim,asolitarygoal--thetop!Itishardforustorealizenowadayshowdifficultitwasforthepioneers.ExceptforoneortwoplacessuchasZermattandChamonix,whichhadrapidlybecomepopular,Alpinevillagestendedtobeimpoverishedsettlementscutofffromcivilizationbythehighmountains.Suchinnsastherewereweregenerallydirtyandflea-ridden;thefoodsimplylocalcheeseaccompaniedbybreadoftentwelvemonthsold,allwasheddownwithcoarsewine.Oftenavalleyboastednoinnatall,andclimbersfoundshelterwherevertheycould--sometimeswiththelocalpriest(whowasusuallyaspoorashisparishioners),sometimeswithshepherdsorcheesemakers.Invariablythebackgroundwasthesame:dirtandpoverty,andveryuncomfortable.Formenaccustomedtoeatingseven-coursedinnersandsleepingbetweenfinelinensheetsathome,thechangetotheAlpsmusthavebeenveryhardindeed.IntheSovietUnionseveralcaseshavebeenreportedrecentlyofpeoplewhocanreadanddetectcolourswiththeirfingers,andevenseethroughsoliddoorsandwalls.Onecaseconcernsan'eleven-year-oldschoolgirl,VeraPetrova,whohasnormalvisionbutwhocanalsoperceivethingswithdifferentpartsofherskin,andthroughsolidwalls.Thisabilitywasfirstnoticedbyherfather.Onedayshecameintohisofficeandhappenedtoputherhandsonthedoorofalockedsafe.Suddenlysheaskedherfatherwhyhekeptsomanyoldnewspaperslockedawaythere,andevendescribedthewaytheyweredoneupinbundles.Vera'scurioustalentwasbroughttothenoticeofascientificresearchinstituteinthetownofUIyanovsk,nearwhereshelives,andinAprilshewasgivenaseriesoftestsbyaspecialcommissionoftheMinistryofHealthoftheRussianFederalRepublic.Duringthesetestsshewasabletoreadanewspaperthroughanopaquescreenand,strangerstill,bymovingherelbowoverachild'sgameofLottoshewasabletodescribethefiguresandcoloursprintedonit;Word格式的文本，已排版。and,inanotherinstance,wearingstockingsandslippers,tomakeoutwithherfoottheoutlinesandcoloursofapicturehiddenunderacarpet.Otherexperimentsshowedthatherkneesandshouldershadasimilarsensitivity.DuringallthesetestsVerawasblindfold;and,indeed,exceptwhenblindfoldshelackedtheabilitytoperceivethingswithherskin.ltwasalsofoundthatalthoughshecouldperceivethingswithherfingersthisabilityceasedthemomentherhandswerewet.Peoplearealwaystalkingabout'theproblemofyouth'.Ifthereisone--whichItakeleavetodoubt--thenitisolderpeoplewhocreateit,nottheyoungthemselves.Letusgetdowntofundamentalsandagreethattheyoungareafterallhumanbeings--peoplejustliketheirelders.Thereisonlyonedifferencebetweenanoldmanandayoungone:theyoungmanhasagloriousfuturebeforehimandtheoldonehasasplendidfuturebehindhim:andmaybethatiswheretherubis.WhenIwasateenager,IfeltthatIwasjustyounganduncertain--thatIwasanewboyinahugeschool,andIwouldhavebeenverypleasedtoberegardedassomethingsointerestingasaproblem.Foronething,beingaproblemgivesyouacertainidentity,andthatisoneofthethingstheyoungarebusilyengagedinseeking.Ifindyoungpeopleexciting.Theyhaveanairoffreedom,andtheyhavenotadrearycommitmenttomeanambitionsorloveofcomfort.Theyarenotanxioussocialclimbers,andtheyhavenodevotiontomaterialthings.Allthisseemstometolinkthemwithlife,andtheoriginsofthings.It'sasiftheywereinsomesensecosmicbeingsinviolentandlovelycontrastwithussuburbancreatures.AllthatisinmymindwhenImeetayoungperson.Hemaybeconceited,illmannered,presumptuousoffatuous,butIdonotturnforprotectiontodrearyclichésaboutrespectforelders--asifmereagewereareasonforrespect.Iacceptthatweareequals,andIwillarguewithhim,asanequal,ifIthinkheiswrong.IamalwaysamazedwhenIhearpeoplesayingthatsportcreatesgoodwillbetweenthenations,andthatifonlythecommonpeoplesoftheworldcouldmeetoneanotheratfootballorcricket,theywouldhavenoinclinationtomeetonthebattlefield.Evenifonedidn'tknowfromconcreteexamples(the1936OlympicGames,forinstance)thatinternationalsportingcontestsleadtoorgiesofhatred,onecoulddeduceitfromgeneralprinciples.Nearlyallthesportspractisednowadaysarecompetitive.Youplaytowin,andthegamehaslittlemeaningunlessyoudoyourutmosttowin.Onthevillagegreen,whereyoupickupsidesandnofeelingoflocalpatriotismisinvolved,itispossibletoplaysimplyforthefunandexercise:butassoonWord格式的文本，已排版。asthequestionofprestigearises,assoonasyoufeelthatyouandsomelargerunitwillbedisgracedifyoulose,themostsavagecombativeinstinctsarearoused.Anyonewhohasplayedeveninaschoolfootballmatchknowsthis.Attheinternationallevelsportisfranklymimicwarfare.Butthesignificantthingisnotthebehaviouroftheplayersbuttheattitudeofthespectators:and,behindthespectators,ofthenations.whoworkthemselvesintofuriesovertheseabsurdcontests,andseriouslybelieve--atanyrateforshortperiods--thatrunning,jumpingandkickingaballaretestsofnationalvirtue.Notallsoundsmadebyanimalsserveaslanguage,andwehaveonlytoturntothatextraordinarydiscoveryofecho-locationinbatstoseeacaseinwhichthevoiceplaysastrictlyutilitarianrole.Togetafullappreciationofwhatthismeanswemustturnfirsttosomerecenthumaninventions.Everyoneknowsthatifheshoutsinthevicinityofawalloramountainside,anechowillcomeback.Thefurtheroffthissolidobstructionthelongertimewillelapseforthereturnoftheecho.Asoundmadebytappingonthehullofashipwillbereflectedfromtheseabottom,andbymeasuringthetimeintervalbetweenthetapsandthereceiptoftheechoesthedepthoftheseaatthatpointcanbecalculated.Sowasborntheecho-soundingapparatus,nowingeneraluseinships.Everysolidobjectwillreflectasound,varyingaccordingtothesizeandnatureoftheobject.Ashoaloffishwilldothis.Soitisacomparativelysimplestepfromlocatingtheseabottomtolocatingashoaloffish.Withexperience,andwithimprovedapparatus,itisnowpossiblenotonlytolocateashoalbuttotellifitisherring,cod,orotherwell-knownfish,bythepatternofitsecho.Afewyearsagoitwasfoundthatcertainbatsemitsqueaksandbyreceivingtheechoestheycouldlocateandsteerclearofobstacles--orlocateflyinginsectsonwhichtheyfeed.Thisecho-locationinbatsisoftencomparedwithradar,theprincipleofwhichissimilar.ChickensslaughteredintheUnitedStates,claimofficialsinBrussels,arenotfittograceEuropeantables.No,saytheAmericans:ourfowlarefine,wesimplycleantheminadifferentway.Thesedays,itisdifferencesinnationalregulations,farmorethantariffs,thatputsandinthewheelsoftradebetweenrichcountries.Itisnotjustfarmerswhoarecomplaining.AnelectricrazorthatmeetstheEuropeanUnion’ssafetystandardsmustbeapprovedbyAmericantestersbeforeitcanbesoldintheUnitedStates,andanAmerican-madedialysismachineneedstheEU’sokaybeforeithitsthemarketinEurope.Asithappens,arazorthatissafeinEuropeisunlikelytoelectrocuteAmericans.So,askbusinessesonbothsidesofWord格式的文本，已排版。theAtlantic,whyhavetwolotsoftestswhereonewoulddo?Politiciansagree,inprinciple,soAmericaandtheEUhavebeentryingtoreachadealwhichwouldeliminatetheneedtodouble-testmanyproducts.TheyhopetofinishintimeforatradesummitbetweenAmericaandEUonMay28th.Althoughnegotiatorsareoptimistic,thedetailsarecomplexenoughthattheymaybehard-pressedtogetadealatall.Why?Onedifficultyistoconstructtheagreements.TheAmericanswouldhappilyreachoneaccordonstandardsformedicaldevicesandthenhammeroutdifferentpactscovering,say,electronicgoodsanddrugmanufacturing.TheEU-followingfinecontinentaltraditions―wantsagreementongeneralprinciples,whichcouldbeappliedtomanytypesofproductsandhaveextendedtoothercountries.AlfredtheGreatactedashisownspy,visitingDanishcampsdisguisedasaminstrel.Inthosedayswanderingminstrelswerewelcomeeverywhere.Theywerenotfightingmen,andtheirharpwastheirpassport.Alfredhadlearnedmanyoftheirballadsinhisyouth,andcouldvaryhisprogrammewithacrobatictricksandsimpleconjuring.WhileAlfred'slittlearmyslowlybegantogatheratAthelney,thekinghimselfsetouttopenetratethecampofGuthrum,thecommanderoftheDanishinvaders.ThesehadsettleddownforthewinteratChippenham:thitherAlfredwent.Henoticedatoncethatdisciplinewasslack:theDaneshadtheselfconfidenceofconquerors,andtheirsecurityprecautionswerecasual.Theylivedwell,ontheproceedsofraidsonneighbouringregions.Theretheycollectedwomenaswellasfoodanddrink,andalifeofeasehadmadethemsoft.AlfredstayedinthecampaweekbeforehereturnedtoAthelney.TheforcethereassembledwastrivialcomparedwiththeDanishhorde.ButAlfredhaddeducedthattheDaneswerenolongerfitforprolongedbattle:andthattheircommissariathadnoorganization,butdependedonirregularraids.So,facedwiththeDanishadvance,Alfreddidnotriskopenbattlebutharriedtheenemy.Hewasconstantlyonthemove,drawingtheDanesafterhim.Hispatrolshaltedtheraidingparties:hungerassailedtheDanisharmy.NowAlfredbeganalongseriesofskirmishes--andwithinamonththeDaneshadsurrendered.Theepisodecouldreasonablyserveasauniqueepicofroyalespionage!TechnologytrendsmaypushSiliconValleybacktothefuture.CarverMead,apioneerinintegratedcircuitsandaprofessorofcomputerscienceattheCaliforniaInstituteofTechnology,notestherearenowworkstationsthatenableengineerstodesign,testandproducechipsrightontheirdesks,muchthewayaneditorcreatesanewsletteronaMacintosh.AsthetimeandcostofmakingachipdriptoaWord格式的文本，已排版。fewdaysandafewhundreddollars,engineersmaysoonbefreetolettheirimaginationssoarwithoutbeingpenalizedbyexpensivefailures.Meadpredictsthatinventorswillbeabletoperfectpowerfulcustomizedchipsoveraweekendattheoffice―spawninganewgenerationofgaragestart-upsandgivingtheU.S.ajumponitsforeignrivalsingettingnewproductstomarketfast.

‘We’vegotmoregarageswithsmartpeople,’Meadobserves.‘Wereallythriveonanarchy.

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AndAsians.Already,orientalsandAsianAmericansconstitutethemajorityoftheengineeringstaffsatmanyValleyfirms.AndChinese,Korean,FilipinoandIndianengineersaregraduatingindrovesfromCalifornia’scolleges.Asthheadsofnext-generationstart-ups,theseAsianinnovatorscandrawoncustomsandlanguagestoforgetighterlinkswithcrucialPacificRimmarket.Forinstance,AlexAu,aStanfordPh.D.fromHongKong,hassetupaTaiwanfactorytochallengeJapannear’locksonthememory-chipmarket.India-bornN.DamodarReddy’stinyCaliforniacompanyreopenedanATTchipplantinKansasCitylastspringwithfinancingfromthestateofMissouri.Beforeitbecomesaretirementvillage,SiliconValleymayproveaclassroomforbuildingaglobalbusiness.Someoldpeopleareoppressedbythefearofdeath.Intheyoungthereisajustificationforthisfeeling.Youngmenwhohavereasontofearthattheywillbekilledinbattlemayjustifiablyfeelbitterinthethoughtthattheyhavebeencheatedofthebestthingsthatlifehastooffer.Butinanoldmanwhohasknownhumanjoysandsorrows,andhasachievedwhateverworkitwasinhimtodo,thefearofdeathissomewhatabjectandignoble.Thebestwaytoovercomeit-soatleastitseemstome----istomakeyourinterestsgraduallywiderandmoreimpersonal,untilbitbybitthewallsoftheegorecede,andyourlifebecomesincreasinglymergedintheuniversallife.Anindividualhumanexistenceshouldbelikeariver--smallatfirst,narrowlycontainedwithinitsbanks,andrushingpassionatelypastbouldersandoverwaterfalls.Graduallytherivergrowswider,thebanksrecede,thewatersflowmorequietly,andintheend,withoutanyvisiblebreak,theybecomemergedinthesea,andpainlesslylosetheirindividualbeing.Themanwho,inoldage,canseehislifeinthisway,willnotsufferfromthefearofdeath,sincethethingshecaresforwillcontinue.Andit,withthedecayofvitality,wearinessincreases,thethoughtofrestwillbenotunwelcome.Ishouldwishtodiewhilestillatwork,knowingthatotherswillcarryonwhatIcannolongerdo,andcontentinthethoughtthatwhatwaspossiblehasbeendone.Whenanyoneopensacurrentaccountatabank,heislendingthebankmoney,repaymentofwhichhemaydemandatanytime,eitherincashorbydrawingachequeinfavourWord格式的文本，已排版。ofanotherperson.Primarily,thebanker-customerrelationshipisthatofdebtorandcreditor--whoiswhichdependingonwhetherthecustomer'saccountisincreditorisoverdrawn.But,inadditiontothatbasicallysimpleconcept,thebankanditscustomerowealargenumberofobligationstooneanother.Manyoftheseobligationscangiverisetoproblemsandcomplicationsbutabankcustomer,unlike,say,abuyerofgoods,cannotcomplainthatthelawisloadedagainsthim.Thebankmustobeyitscustomer'sinstructions,andnotthoseofanyoneelse.When,forexample,acustomerfirstopensanaccount,heinstructsthebanktodebithisaccountonlyinrespectofchequesdrawnbyhimself.Hegivesthebankspecimensofhissignature,andthereisaveryfirmrulethatthebankhasnorightorauthoritytopayoutacustomer'smoneyonachequeonwhichitscustomer'ssignaturehasbeenforged.Itmakesnodifferencethattheforgerymayhavebeenaveryskilfulone:thebankmustrecognizeitscustomer'ssignature.Forthisreasonthereisnorisktothecustomerinthemodernpractice,adoptedbysomebanks,ofprintingthecustomer'snameonhischeques.Ifthisfacilitatesforgeryitisthebankwhichwilllose,notthecustomer.Thedeepestholesofallaremadeforoil,andtheygodowntoasmuchas25,000feet.Butwedonotneedtosendmendowntogettheoilout,aswemustwithothermineraldeposits.Theholesareonlyborings,lessthanafootindiameter.Myparticularexperienceislargelyinoil,andthesearchforoilhasdonemoretoimprovedeepdrillingthananyotherminingactivity.Whenithasbeendecidedwherewearegoingtodrill,weputupatthesurfaceanoilderrick.Ithastobetallbecauseitislikeagiantblockandtackle,andwehavetolowerintothegroundandhauloutofthe.groundgreatlengthsofdrillpipewhicharerotatedbyanengineatthetopandarefittedwithacuttingbitatthebottom.Thegeologistneedstoknowwhatrocksthedrillhasreached,soeverysooftenasampleisobtainedwithacoringbit.Itcutsacleancylinderofrock,fromwhichcanbeseenhestratathedrillhasbeencuttingthrough.Oncewegetdowntotheoil,itusuallyflowstothesurfacebecausegreatpressure,eitherfromgasorwater,ispushingit.Thispressuremustbeundercontrol,andwecontrolitbymeansofthemudwhichwecirculatedownthedrillpipe.Weendeavourtoavoidtheold,romanticideaofagusher,whichwastesoilandgas.Wewantittostaydowntheholeuntilwecanleaditoffinacontrolledmanner.Beyondtwoorthreedays,theworld’sbestweatherforecastsarespeculative,andbeyondsixorseventheyareworthless.Word

格式的文本，已排版。TheButterflyEffectisthereason.Forsmallpiecesofweather

―aaglobalforecaster,smallcanmeanthunderstormsandblizzardsCanypredictiondeterioratesrapidly.Errorsanduncertaintiesmultiply,cascadingupwardthroughachainofturbulentfeatures,fromdustdevilsandsquallsuptocontinent-sizeeddiesthatonlysatellitescansee.Themodernweathermodelsworkwithagridofpointsoftheorderofsixtymilesapart,andevenso,somestartingdatahastobeguessed,sincegroundstationsandsatellitescannotseeeverywhere.Butsupposetheearthcouldbecoveredwithsensorsspacedonefootapart,risingatone-footintervalsallthewaytototopoftheatmosphere.Supposeeverysensorgivesperfectlyaccuratereadingsoftemperature,pressure,humidity,andanyotherquantityameteorologistwouldwant.Preciselyatnoonaninfinitelypowerfulcomputertakesallthedataandcalculateswhatwillhappenateachpointat12.01,then12.02,then12.03.ThecomputerwillstillbeunabletopredictwhetherPrinceton,NewJersey,willhavesunorrainonadayonemonthaway.Atnoonthespacesbetweenthesensorswillhidefluctuationsthatthecomputerwillnotknowabout,tinydeviationsfromtheaverage.By1.201,thosefluctuationswillalreadyhavecreatedsmallerrorsonefootaway.Soontheerrorswillhavemultipliedtotheten-footscale,andsoonuptothesizeoftheglobe.Twofactorsweighheavilyagainsttheeffectivenessofscientificinindustry.Oneisthegeneralatmosphereofsecrecyinwhichitiscarriedout,theotherthelackoffreedomoftheindividualresearchworker.Insofarasanyinquiryisasecretone,itnaturallylimitsallthoseengagedincarryingitoutfromeffectivecontactwiththeirfellowscientistseitherinothercountriesorinuniversities,oreven,oftenenough,inotherdepartmentsofthesamefirm.Thedegreeofsecrecynaturallyvariesconsiderably.Someofthebiggerfirmsareengagedinresearcheswhichareofsuchgeneralandfundamentalnaturethatitisapositiveadvantagetothemnottokeepthemsecret.Yetagreatmanyprocessesdependingonsuchresearcharesoughtforwithcompletesecrecyuntilthestageatwhichpatentscanbetakenout.Evenmoreprocessesareneverpatentedatallbutkeptassecretprocesses.Thisappliesparticularlytochemicalindustries,wherechancediscoveriesplayamuchlargerpartthantheydoinphysicalandmechanicalindustries.Sometimesthesecrecygoestosuchanextentthatthewholenatureoftheresearchcannotbementioned.Manyfirms,forinstance,havegreatdifficultyinobtainingtechnicalorscientificbooksfromlibrariesbecausetheyareunwillingtohavetheirnamesenteredashavingtakenoutsuchandsuchabookforfeartheagentsofotherfirmsshouldbeabletotracethekindofresearchtheyarelikelytobeundertaking.Word格式的文本，已排版。Intheorganizationofindustriallifetheinfluenceofthefactoryuponthephysiologicalandmentalstateoftheworkershasbeencompletelyneglected.Modernindustryisbasedontheconceptionofthemaximumproductionatlowestcost,inorderthatanindividualoragroupofindividualsmayearnasmuchmoneyaspossible.Ithasexpandedwithoutanyideaofthetruenatureofthehumanbeingswhorunthemachines,andwithoutgivinganyconsiderationtotheeffectsproducedontheindividualsandontheirdescendantsbytheartificialmodeofexistenceimposedbythefactory.Thegreatcitieshavebeenbuiltwithnoregardforus.Theshapeanddimensionsoftheskyscrapersdependentirelyonthenecessityofobtainingthemaximumincomepersquarefootofground,andofofferingtothetenantsofficesandapartmentsthatpleasethem.Thiscausedtheconstructionofgiganticbuildingswheretoolargemassesofhumanbeingsarecrowdedtogether.Civilizedmenlikesuchawayofliving.Whiletheyenjoythecomfortandbanalluxuryoftheirdwelling,theydonotrealizethattheyaredeprivedofthenecessitiesoflife.Themoderncityconsistsofmonstrousedificesandofdark,narrowstreetsfullofpetrolfumes,coaldust,andtoxicgases,tornbythenoiseofthetaxi-cabs,lorriesandbuses,andthrongedceaselesslybygreatcrowds.Obviously,ithasnobeenplannedforthegoodofitsinhabitants.IntheearlydaysofthesettlementofAustralia,enterprisingsettlersunwiselyintroducedtheEuropeanrabbit.ThisrabbithadnonaturalenemiesintheAntipodes,sothatitmultipliedwiththatpromiscuousabandoncharacteristicofrabbits.Itoverranawholecontinent.Itcauseddevastationbyburrowingandbydevouringtheherbagewhichmighthavemaintainedmillionsofsheepandcattle.Scientistsdiscoveredthatthisparticularvarietyofrabbit(andapparentlynootheranimal)wassusceptibletoafatalvirusdisease,myxomatosis.Byinfectinganimalsandlettingthemlooseintheburrows,localepidemicsofthisdiseasecouldbecreated.Lateritwasfoundthattherewasatypeofmosquitowhichactedasthecarrierofthisdiseaseandpasseditontotherabbits.Sowhiletherestoftheworldwastryingtogetridofmosquitoes,Australiawasencouragingthisone.Iteffectivelyspreadthediseasealloverthecontinentanddrasticallyreducedtherabbitpopulation.ltlaterbecameapparentthatrabbitsweredevelopingadegreeofresistancetothisdisease,sothattherabbitpopulationwasunlikelytobecompletelyexterminated.Therewerehopes,however,thattheproblemoftherabbitwouldbecomemanageable.Ironically,Europe,whichhadbequeathedtherabbitasapesttoAustraliaacquiredthisman-madediseaseasapestilence.AFrenchphysiciandecidedtogetridofthewildrabbitsonhisownestateandintroducedmyxomatosis.ItWord格式的文本，已排版。didnot,however,remainwithintheconfinesofhisestate.ItspreadthroughFrancewherewildrabbitsarenotgenerallyregardedasapestbutasasportandausefulfoodsupply,anditspreadtoBritainwherewildrabbitsareregardedasapestbutwheredomesticatedrabbits,equallysusceptibletothedisease,arethebasisofaprofitablefurindustry.ThequestionbecameoneofwhetherMancouldcontrolthediseasehehadinvented.Therehaslongbeenasuperstitionamongmarinersthatporpoiseswillsavedrowningmenbypushingthemtothesurface,orprotectthemfromsharksbysurroundingthemindefensiveformation.MarineStudiobiologistshavepointedoutthat,howeverintelligenttheymaybe,itisprobablyamistaketocreditdolphinswithanymotiveoflife-saving.Ontheoccasionswhentheyhavepushedtoshoreanunconscioushumanbeingtheyhavemuchmorelikelydoneitoutofcuriosityorforsport,asinridingthebowwavesofaship.In1928someporpoiseswerephotographedworkinglikebeaverstopushashoreawaterloggedmattress.If,ashasbeenreported,theyhaveprotectedhumansfromsharks,itmayhavebeenbecausecuriosityattractedthemandbecausethescentofapossiblemealattractedthesharks.Porpoisesandsharksarenaturalenemies.Itispossiblethatuponsuchanoccasionabattleensued,withthesharksbeingdrivenawayorkilled.Whetheritbebird,fishorbeast,theporpoiseisintriguedwithanythingthatisalive.Theyareconstantlyaftertheturtles,theFerdinandsofmarinelife,whopeacefullysubmittoallsortsofindignities.Oneyoungcalfespeciallyenjoyedraisingaturtletothesurfacewithhissnoutandthenshovinghimacrossthetanklikeanaquaplane.Almostanydayayoungporpoisemaybeseentryingtoturna300-poundseaturtleoverbystickinghissnoutundertheedgeofhisshellandpushingupfordearlife.Thisisnoteasy,andmayrequiretwoporpoisesworkingtogether.Inanothergame,astheturtleswimsacrosstheoceanarium,thefirstporpoiseswoopsdownfromaboveandbuttshisshellwithhisbelly.Thisknockstheturtledownseveralfeet.Henosoonerrecovershisequilibriumthanthenextporpoisecomesalongandhitshimanothercrack.Eventuallytheturtlehasbeenbuttedallthewaydowntothefloorofthetank.Heisnowsatisfiedmerelytotrytostandup,butassoonashedoessoaporpoiseknockshimflat.Theturtleatlastgivesupbypullinghisfeetunderhisshellandthegameisover.Itisfairlyclearthatthesleepingperiodmusthavesomefunction,andbecausethereissomuchofitthefunctionwouldseemtobeimportant.Speculationsaboutitsnaturehavebeengoingonforliterallythousandsofyears,andoneoddfindingthatmakestheproblempuzzlingisthatitlooksverymuchasifsleepingisnotsimplyamatterofgivingtheWord格式的文本，已排版。bodyarest.'Rest',intermsofmusclerelaxationandsoon,canbeachievedbyabriefperiodlying,orevensittingdown.Thebody'stissuesareself-repairingandself-restoringtoadegree,andfunctionbestwhenmoreorlesscontinuouslyactive.Infactabasicamountofmovementoccursduringsleepwhichisspecificallyconcernedwithpreventingmuscleinactivity.Ifitisnotaquestionofrestingthebody,thenperhapsitisthebrainthatneedsresting?Thismightbeaplausiblehypothesiswereitnotfortwofactors.Firsttheelectroencephalograph(whichissimplyadeviceforrecordingtheelectricalactivityofthebrainbyattachingelectrodestothescalp)showsthatwhilethereisachangeinthepatternofactivityduringsleep,thereisnoevidencethatthetotalamountofactivityisanyless.Thesecondfactorismoreinterestingandmorefundamental.Inl960anAmericanpsychiatristnamedWilliamDementpublishedexperimentsdealingwiththerecordingofeye-movementsduringsleep.Heshowedthattheaverageindividual'ssleepcycleispunctuatedwithpeculiarburstsofeye-movements,somedriftingandslow,othersjerkyandrapid.Peoplewokenduringtheseperiodsofeye-movementsgenerallyreportedthattheyhadbeendreaming.Whenwokenatothertimestheyreportednodreams.Ifonegroupofpeopleweredisturbedfromtheireye-movementsleepforseveralnightsonend,andanothergroupweredisturbedforanequalperiodoftimebutwhentheywerenotexhibitingeye-movements,thefirstgroupbegantoshowsomepersonalitydisorderswhiletheothersseemedmoreorlessunaffected.Theimplicationsofallthiswerethatitwasnotthedisturbanceofsleepthatmattered,butthedisturbanceofdreaming.Howitcameaboutthatsnakesmanufacturedpoisonisamystery.Overtheperiodstheirsaliva,amild,digestivejuicelikeourown,wasconvertedintoapoisonthatdefiesanalysiseventoday.Itwasnotforceduponthembythesurvivalcompetition;theycouldhavecaughtandlivedonpreywithoutusingpoisonjustasthethousandsofnon-poisonoussnakesstilldo.Poisontoasnakeismerelyaluxury;itenablesittogetitsfoodwithverylittleeffort,nomoreeffortthanonebite.Andwhyonlysnakes?Cats,forinstance,wouldbegreatlyhelped;norunningrightswithlarge,fierceratsortussleswithgrownrabbitsjustabiteandnomoreeffortneeded.Infactitwouldbeanassistancetoallthecarnivorae--thoughitwouldbeatwo-edgedweapon-Whentheyfoughteachother.But,ofthevertebrates,unpredictableNatureselectedonlysnakes(andonelizard).OnewondersalsowhyNature,withsomesnakesconcoctedpoisonofsuchextremepotency.Intheconversionofsalivaintopoisononemightsupposethatafixedprocesstookplace.Itdidnot;somesnakesmanufacturedapoisondifferentineveryrespectfromthatofothers,asdifferentasarsenicisfromstrychnine,andhavingdifferenteffects.Onepoisonactsonthenerves,theotherontheblood.Word格式的文本，已排版。Themakersofthenervepoisonincludethemambasandthecobrasandtheirvenomiscalledneurotoxic.Vipers(adders)andrattlesnakesmanufacturethebloodpoison,whichisknownashaemolytic.Bothpoisonsareunpleasant,butbyfarthemoreunpleasantisthebloodpoison.Itissaidthatthenervepoisonisthemoreprimitiveofthetwo,thatthebloodpoisonis,sotospeak,anewerproductfromanimprovedformula.Bethatasitmay,thenervepoisondoesitsbusinesswithmanfarmorequicklythanthebloodpoison.This,however,meansnothing.Snakesdidnotacquiretheirpoisonforuseagainstmanbutforuseagainstpreysuchasratsandmice,andtheeffectsontheseofviperinepoisonisalmostimmediate.WilliamS.Hartwas,perhaps,thegreatestofallWesternstars,forunlikeGaryCooperandJohnWayneheappearedinnothingbutWesterns.From1914to1924hewassupremeandunchallenged.ItwasHartwhocreatedthebasicformulaoftheWesternfilm,anddevisedtheprotagonistheplayedineveryfilmhemade,thegood-badman,theaccidental,nobleoutlaw,orthehonestbutframedcowboy,orthesheriffmadesuspectbyviciousgossip;inshort,theindividualinconflictwithhimselfandhisfrontierenvironment.UnlikemostofhiscontemporariesinHollywood,Hartactually'knewsome