Iwaited.MyJaguarandLizzie'shelicoptersatuselesslyonthetarmac.Lovelyfasttransportatastandstill.

Quippcamebackquitesoon.

Lizziesaysifyousaythisisurgent,it'surgent.'

'It'surgent,'Isaid.

'Right.Inthatcase,flyuphereontheshuttle.We'llmeetyouatEdinburghAirport.Say...oneo'clock?Soonafter?''Er...'Ibegan.

Orcourseyoucan'tbringthehorsewithyou,'Quippsaid,'justbringsometicks.'

'ButIcan'tactuallyseethem.'

'Quitenormal.They'reverysmall.Usesoap.'

Surreal.

'Wetabarofsoapuntilit'ssticky,'hesaid.'Rubitoverthehorse.Ifyoufindanyroundbrownspecksonthesoap,you'vegotticks.'

'Butwon'ttheydie?'

'Myfriendsaysperhapsnot,ifyoudon'twastetimeonthewayhere,andanyway,itmightnotmatter.Oh,yes,bringabloodsamplefromthehorse.'

IopenedmymouthtosayitwouldtakeanhourormoretogetthevetbutLizzie'svoiceinmyearforestalledme.

'There'sahypodermicneedleandasyringeinmybathroomcupboard,'hesaid.'LeftoverfrommywaspallergydayswhenIlivedathome.Isawittheotherday.Usethat.'

'ButLizzie...'

'Getonanddoit,'shecommanded,andQuipp'svoicesaid'Seeyouonthelunchtimeshuttle.Phoneifyou'regoingtobelater.'

'Yes,'Isaiddazed,andheardthedisconnectingclickattheotherend.Afarfromabsent-mindeddon,Ireflected.Agoodmatchformysister.

WhatPetermanhimselfwouldthinkaboutmystickingneedlesintohimIdreadedtothink.IwentupstairstothelittlepinkandgoldbathroomoffLizzie'sbedroomandfoundthesyringe,a.s.she'dsaid,inthemirror-frontedcabinetthere.Thesyringe,disposable,instructions'forsingleuseonly',wasinsideanopaquewhiteplasticenvelopeandlookedmuchtoosmallforanythingequine.Still,Lizziehadsaidtouseit,soItookitdownstairsalongwithhercakeofsoap,moistenedtostickiness,andapproachedtheoldfellowinthegarden.

Hisapathyseemedcomplete.ImerelyheldhisforelockwhileItracedthevisibleveinrunningalonghislowerjaw,stickingthefineneedleintoitgently.Hisheadremainedstill,asifhe'dfeltnothing.IfoundIneededtwohands,inmyinexperience,topullbacktheplungerinordertodrawbloodintothesyringe,andeventhenheremainedunmoving,asifhalfasleep.Thelittlesyringefilledeasilywiththeredstuff.Ipulledtheneedleoutagain,laidthesyringeaside,pickedupthebarofsoapandwipeditaroundPeterman'sheadanddownhisneck.Despitemydoubtsanddisbelieftherewere,afterthreeorfourpa.s.ses,afewdiscernibledarkbrownpinheaddotsonthesoftwhitesurface.

PetermanwentonpayingnoattentionasIpackedmytrophiesintoanestofscrumpledtissuesinsideaplasticfoodcontainerfromthekitchenandfirmlyclosedthelid.AutomaticallyIraisedahandtopattheoldfellow,tosaythanks,andinmid-gesturestoppeddead.Whatif,Ithought,inpattinghim,Itransferredhistickstomyself?WhatifI'dalreadydoneit?Woulditmatter?Ihadn'teventhoughtofwearingprotectivegloves.

Shrugging,Ileftmyoldfriendunpatted,washedmyhandsinthekitchen,andwithinfiveminutesIwa.s.spinningalongtheroadinthedirectionofHeathrowAirport.

IphonedIsobelontheway.

'You'regoingwhere?shesaid.

'Edinburgh.BeadearandkeepallthephonelinesswitchedtoyouuntilIgetback.Bonus,ofcourse.'

'OK.Howlongw.i.l.l.youbegone?'

'Adayortwo.I'llkeepphoningyou,tostayintouch.'

ByluckIhadaclearruntotheairport,parkedintheshort-staycarparkandcaughtthelastseatonthenoonshuttleatnothingfasterthanaflat-outsprint.Myonlyluggagewasthekitchenfoodcontainerandtheenvelopeofmoneyfromthesafe.MyclotheswerethejeansandsweatshirtI'dworntowork.Everyoneelseontheaircraftseemedtobesportinghugescarlet-and-whitescarvesandloudlysingingbawdysongs.'SwingLow,SweetChariot',withtheobscenestofgestures.Lifegrewsteadilyweirder.Iheldthecontaineronmylapandsleptawaythehourintheair.

Lizziewaswaitingattheotherendbesideamanwholookedmorelikeaskiinstructorthanaprofessoroforganicchemistry,theimpactofhisdarkbeardlessgoodlooksheightenedbyarainbowjacketstraightofftheslopes.

Quipp,'heintroducedhimself,extendingahand.'Isupposeyou'reFreddie.'

AsI'djustkissedLizzie,thisseemedareasonablea.s.sumption.

Itoldhimyou'dgethere,'shesaid.'Heworkedoutthatyoucouldn'tdoitinthetime.Itoldhimyourjockeyinstinctsmadeyoufasteracrosscountrythanahurricane.'

Hurricanesareslowacrosscountry,'Isaid,'actually.'

Quipplaughed.'Sotheyare.Forwardspeed,notmuchmorethantwenty-fivemilesanhour.Right?'

'Right,'Isaid.

'Comeon,then.'Heeyedthekitchencontainer.'You'vebroughtthegoods?We'regoingstraighttothelab.Notimetowaste.'

QuippdroveaRenaultwithavervetomatchhisjacket.Wepulledupatwhatlookedlikeatradesmen'sbackentranceofaprivatehospitalandenteredalightfeaturelesscorridorthatledroundacornertoapairofswingdoorswith'McPhersonFoundation'paintedinblacklettersonnon-see-throughgla.s.s.

Quipppushedfamiliarlythroughthedoors,LizzieandIfollowing,andweenteredfirstavestibule,andthenaroomwindowedsolelybyskylights.

Frompegsinthevestibule,Quipp.i.s.suedtoeachofusawhitelaboverall-coatwhichb.u.t.tonedattheneckandneededtobetiedroundthewaistwithtapes.InsidethelabitselfwemetamansimilarlydressedwhoturnedfromamicroscopeonourarrivalandsaidtoQuipp,'Thishadbetterbegood,yousonofab.i.t.c.h.I'msupposedtobeattheInternationalrugbymatchatMurrayfield.'

Quipp,unabashed,introducedhimtomeasGuggenheim,theresidentnutter.

Guggenheim,whoseemed,likeQuipp,toprefertobeidentifiedsolelybyhislastname,wasaudiblyAmericanandvisiblyaboutasyoungasthecomputerwizard.

'Disregardhisyouth,'Quippadvised.'RememberthatIsaacNewtonwastwenty-fourwhenhediscoveredthebinomialtheoremin1666.'

I'llremember,'Isaiddryly.

I'mtwenty-five,'Guggenheimsaid.'Let'sseewhatyou'vebrought.'

Hetooktheplasticcontainerfrommeandretreatedtooneoftheworkbenchesthatlinedtwoofthewalls.Withtimetolookaround,itseemedtomethatexceptforthemicroscopetherewasn'tasinglepieceofequipmenttherethatIcouldidentify.GuggenheimmovedinthismysteriousterritorywiththecertaintyofaRubikroundhiscube.

Hewa.s.slightinbuildwithlightbrowncrinklyhairandthewell-disciplinedeyesofhabitualconcentration.Hetransferredoneofthebrowndotsfromthesoaptoaslideandtookaquicklookat.i.tunderthemicroscope.

'Well,well,well,wehaveatick.Nowwhatdoyousupposehe'scarrying?'

'Er,'Isaid,but.i.tappearedthatGuggenheim'squestionwasrhetorical.

'Ifitcamefromahorse,'hesaidcheerfully,'perhapsweshouldbelookingforEhrlichiaristicii.Whatdoyouthink?DoesEhrlichiaristiciispringtomind?'

'Itdoesnot,'Isaid.

Guggenheimlookedupfromhismicroscopeingoodhumour.'Isthehorseill?'heasked.

Thehorseisstandingstilllookingdepressed,ifthatdoesn'tsoundfanciful.'

'Depressionisclinical,'hesaid.'Anythingelse?Fever?'

'Ididn'ttakehistemperature.'IthoughtbacktoPeterman'sbehaviourthatmorning.'Hewouldn'teat,'Isaid.

Guggenheimlookedhappy.'Depression,anorexiaandfever,'hesaid,'cla.s.sicsymptoms.'HelookedatLizzie,Quippandmyself.'Whydon'tyouthreegoawayforabit?Givemeanhour.Imightfindyousomeanswers.I'mnotpromising.We'vesomepowerfulmicroscopeshereandwe'redealingwithorganismsontheedgeofvisibility.Anyway...anhour.'

Weretreatedasinstructed,leavingourlabcoatsinthevestibule.Quippdroveustohislodgings,whichweremasculineandbookishbutboreunmistakablesignsofLizzie'soccupation,thoughherexpressionforbademetocomment.Shemadecoffee.Quipptookhiscupwiththemurmuredthanksoffamiliarity.

'How'smylittleRobinson?'Lizzieaskedme.'Stillinthesameplace?'

'Alow-loader'scomingonMondaytobringituphere.'

'Tellthemtobecareful!'

'It'llreachyouincottonwool'

'They'llhavetodisa.s.sembletherotorlinkage...'

Wedrankthecoffee,strongandblack.

ItelephonedIsobel.Allgoingwell,shereported.

'WhatexactlyistheMcPhersonFoundation?'IaskedQuipp.

'Scottishphilanthropist,'Quippsaidsuccinctly.'Alsoatinyuniversitygrant.Smallpublicfunding.Itha.s.state-of-the-artelectronmicroscopesandatpresenttworesidentgeniuses,oneofwhomyoumet.Itpushesouttnefrontiersofknowledge,andpeoplein.o.bscureplacesceasedyingofobscureillnesses.'Hedranksomecoffee.'Guggenheim'sspecialityistheidentificationofthevectorsofEhrlichiae.'

'Idon'tspeakthatlanguage,'Isaid.

'Ah.Thenyouwon'tunderstandthatwhenIaskedhimaboutticksonhorseshewas,forhim,riveted.It'sremotelypossiblethatyou'vesolvedamysteryforhim.NothinglesswouldhavetornhimawayfromMurrayfield.'

'Well...whatareerlic...whateveryousaid?'

'Ehrlichiae'?Theyare,'hesaidwithatouchofmischief,'pleomorphicorganismssymbioticinandtransmittedbyarthropodvectors.Ingeneral,thatis.'

'Quipp!'Lizzieproteted.

Herelented.'They'reparasiticorganismsspreadbyticks.Thebestknownmakedogsandcattleill.GuggenheimdidsomeworkonEhrlichiaeinhorsesbackinAmerica.He'llhavetotellyouabout.i.thimself.AllI'msureofisthathe'stalkingaboutanewdiseasethataroseonlyinthemid-nineteeneighties.'

'Anewdisease?'Iexclaimed.

'Nature'salwaysevolving,'Quippsaid.'Lifeneverstandsstill.Diseasescomeandgo.AIDSisnew.Somethingevenmoredestructivemaybejustroundthecorner.'

'Howfearful,'Lizzieprotested,frowning.

'DearLiz,youknowit'spossible.'Helookedatme.'Guggenheimhasatheorythatthedinosaursdiednotofcataclysmicweatherupheavalsbutoftick-bornerickettsial-likepathogens-andthose,beforeyouask,areparasiticmicroorganismsthatcausefeversliketyphus.Guggenheimthinkstheticksandtheirparasitesdiedwiththeirhosts,leavingnotrace.'

Ipondered.'Couldyoutransporttheseer-pathogens-inviraltransportmedium?Thestuffinthosesmallgla.s.stubes?'

Helookedmomentarilystartledbutdecisivelyshookhishead.'No.Notpossible.Ehrlichiaearen'tviruses.AsfarasIknow,theywon'tliveatallinanysortofmediumoronaculturedish,whichmakestheresearchdifficult.No.Whateverwasinyourvirustransportmedium,itdefinitelydidnotcomefromticks.'

'Thatdoesn't,'Isaidruefully,'makeanythinganyclearer.'

'Lizzieisanastrophysicist,'hesaid,'listeningtothecosmicripplefromthebeginningoftheuniverse,andGuggenheimlooksinwardintoparasiticelementarybodiesdetectableonlybymagnifyingthemamilliontimesinabeamofelectronsinsteadoflight.Outerdeepsandinnerdeeps,withourpunyintellectshereandnowtryingtoseeandunderstandincrediblemysteries.'Hesmiledself-deprecatingly.'Thehumblingtruthisthatwithallourdiscoveries,we'reonlyonthefringeofknowledge.'

'Butfromthepracticalpointofview,'Isaid,'allweneedtoknowisthata.r.s.eniccancuresyphilis.'

'You'renoscientist!'heaccusedme.'YouneedGuggenheimlookalikestofindoutthata.r.s.eniccancuresyphilis.'

Theultimatesquelch,Iacknowledged.Lizziepattedmyshoulderkindly.

'Isupposeyoudidn'tknow,'Quippsaid,'that.i.twasEhrlichhimself,afterwhomEhrlichiaearenamed,whofirstshowedsynthetica.r.s.enictobeactiveagainstsyphilis?'

'No,'Isaid,astonished.'I'veneverheardofEhrlich.'

'Germanscientist.n.o.belprizewinner.Afounderofimmunology,pioneerofchemotherapy.Died,1915.You'llneverforgethim.'

In1915,Ithought,Pommernwonthewar-timeDerby.Thequirksoflifewereendless.

AfteranhourQuippdroveusbacktotheMcPhersonFoundationtofindGuggenheimpaleandtrembling,apparentlyfromexcitement.

'Wheredidthesetickscomefrom?'hedemanded,a.s.soonasweappearedinourwhitegear.'DidtheycomefromAmerica?'

'IthinktheycamefromFrance.'

'When?'

'LastMonday.Onarabbit.'

Hepeeredatme,a.s.sessingthings.'Yes.Yes.Theycouldhavetravelledonarabbit.Theywouldn'tlivelongonsoap.b.u.t.transferthemfromahorsetoarabbitbysoap...there'snoreasonwhytheycouldn'tliveonarabbit...Therabbitwouldn'tbereceptivetothehorseEhrlichiae...therabbitcouldcarrythelivetickswithimpunity.'

Andthenonecouldtransferthetickstoadifferenthorse?'Iasked.

'It'spossible.Yes,yes,Ican'tseewhynot.'

Ican'tseewhy,'Lizziesaid.Whywouldanyonedothat?'

Research,'Guggenheimsaidwithcertainty.

Lizzielookedatmedoubtfullybutdidn'tpursueit.

'See,'hesaidtome,'equineehrlichiosisisknowninAmerica.I'veseenitinMaryland,andPennsylvania,thoughit'saverynewdisease.Nottenyearsoldyet.Rare.Whenit'scausedbyEhrlichiaristiciiit'sbeencalledPotomachorsefever.That'sbecauseit'sbeenfoundmostlynearbigriverslikethePotomac.HowdidtheseticksgettoFrance?'

'FranceimportsracehorsesbredinAmerica.SodoesBritain,cometothat.'

'Thenwhytherabbits?'

'Suppose,'Isaid,'thatyouknowwheretofindtheticksinFrancebutnotinEngland.'