Kurtzis, or ratherwas, a Company myth. Before he actuallymeetshim, Marlow hasheard so muchabouthimthat he hasformedhisownideasaboutthislegendary figure, butwhen he finallyseeshim, he describesKurtzaslost in a world to whichnormalstandards do notapply. In the second paragraph MarlowseesKurtzas the supreme example of a man whohasleftcivilisationbehind and hassuccumbed to theappeal of darkness, not just externaldarkness – the jungle with itssavagerites – butinternaldarkness.
Deep down in the recesses of the human mindthere are areaswhich are onlyrevealedwhen the familiarstructures of civilisationdisappear. Here Conrad, through Marlow, directlyconfrontshisreader, warninghimthathisapparentlyunshakeablecivilised life reallystands on weakfoundations.
In the last paragraphcolonialismisjustified in terms of the idea of the ennobling mission of the Europeansin Africa, in a report written by Kurtz some time before. Its high idealismisbetrayed by a hasty noteat the foot of a paragraph: “Exterminateall the brutes”.

From Chapter 2
“And the loftyfrontal bone of MrKurtz! Theysay the hairgoes on growingsometimes, butthis – ah – specimen, wasimpressivelybald. The wilderness1 hadpattedhim on the head, and, behold, itwaslike a ball – an ivoryball; ithadcaressedhim, and – lo! – he hadwithered; ithadtakenhim, lovedhim, embracedhim, gotintohisveins, consumedhisflesh, and sealedhis soul to itsownby the inconceivableceremonies of some devilishinitiation. He wasitsspoiledand pamperedfavourite. [...]
Youshouldhaveheardhimsay, ‘My ivory.’ Oh yes, I heardhim. ‘My Intended,myivory, my station, myriver, my –’ everythingbelonged to him. It made meholdmybreath in expectation of hearing the wildernessburstinto a prodigiouspeal of laughterthatwould shake the fixed stars2 in theirplaces. Everythingbelongedto him – butthatwas a trifle. The thingwas to know what he belonged to,howmanypowers of darknessclaimedhim for theirown. Thatwas the reflectionthat made youcreepyall over. Itwasimpossible – itwasnotgood for oneeither – trying to imagine. He hadtaken a high seatamongst the devils of theland – I meanliterally. Youcan’tunderstand. How couldyou? – with solidpavementunder yourfeet, surrounded by kindneighbours ready to cheeryou or tofall on you, steppingdelicatelybetween the butcher and the policeman, in the holyterror of scandal and gallows3 and lunaticasylums – how can youimaginewhatparticularregion of the first ages a man’suntrammelledfeetmay take himinto by the way of solitude – uttersolitudewithout a policeman – by the way ofsilence – uttersilence, where no warning voice of a kindneighbour can be heardwhispering of public opinion? Theselittlethings make all the greatdifference.
Whenthey are goneyou must fall back uponyourown innate strength, uponyourowncapacity for faithfulness. Of courseyoumay be toomuch of a foolto go wrong – toodulleven to know you are beingassaulted by the powers of darkness. [...]”
“The original Kurtz4hadbeeneducatedpartly in England, and – as he wasgoodenough to sayhimself – hissympathieswere in the right place. His motherwashalf-English, hisfatherwashalf-French. All Europe contributed to the makingof Kurtz; and by-and-by I learnedthat, mostappropriately, the InternationalSociety for the Suppression of Savage Customshadintrustedhim with the makingof a report, for its future guidance. And he hadwrittenit, too. I’veseenit.
I’vereadit. Itwaseloquent, vibrating with eloquence, buttoo high-strung, Ithink. Seventeenpages of closewriting he hadfound time for! Butthis musthavebeenbeforehis – letussay – nerves, went wrong,5 and causedhim to preveryside atcertainmidnightdancesending with unspeakablerites, which – as faras I reluctantlygathered from what I heardatvarioustimes – wereoffered up6 to him – do youunderstand? – to MrKurtzhimself. Butitwas a beautiful pieceof writing. The opening paragraph, however, in the light of later information,7strikes me nowasominous. He began with the argumentthatwewhites, fromthe point of developmentwehadarrivedat, ‘must necessarilyappear to them [savages] in the nature of supernaturalbeings – weapproachthem with the mightas of a deity,’ and so on, and so on. ‘By the simpleexercise of our will8 we can exert a power for goodpracticallyunbounded,’ etc. etc. From that pointhe soared and took me with him. The perorationwasmagnificent, thoughdifficultto remember, you know. Itgave me the notion of an exoticImmensityruledby an augustBenevolence. It made me tingle with enthusiasm. Thiswas theunbounded power of eloquence – of words – of burningnoblewords. Therewere no practical hints9 to interrupt the magiccurrent of phrases, unless a kindof note at the foot of the last page, scrawledevidentlymuch later,10 in an unsteadyhand, may be regardedas the exposition of a method.11Itwasverysimple, and at the end of thatmoving appeal to everyaltruistic sentiment itblazedatyou, luminous and terrifying, like a flash of lightning in a serene sky:
‘Exterminateall the brutes!’”

Notes:

  1. wilderness: the savagesurroundings, to be understood more as the totalabsence of civilisation and the usual moral restraintsthanas a specificgeographicalplace.
  2. fixed stars: stars are so far from earththattheyappearmotionless, unlikeplanets, comets, etc.
  3. holy... gallows: civilised man actscivillybecause he hasbeenbrought up to fearscandal and the penalties of the law.
  4. The originalKurtz: Kurtzas he wasbeforecominghere.
  5. this... wrong: thishappenedbefore he gave the first signs of moral weakness.
  6. offered up: i.e. as to a pagangod.
  7. in the... information: consideringwhat I learnedlater.
  8. By the... will: ifwe just want to.
  9. no practicalhints: Kurtz’s report was full of high words and intentionsbutitcontained no practicalsuggestions on how to exercise the power for goodmentionedabove.
  10. scrawled... muchlater: addedlater by Kurtzhimself.
  11. the exposition... method: i.e. a practicalhint, suggestion.