Quote 97
"I had then, as you remember, just returned to London after a lot of Indian Ocean, Pacific, China Seas - a regular dose of the East - six years or so, and I was loafing about, hindering you fellows in your work and invading your homes, just as though I had got a heavenly mission to civilize you." (1.16)
Marlow makes fun of the colonist's motto—to civilize savages—by comparing it to an idle traveler imposing himself on hosts too generous to make him leave. The implication is that the colonists' arrival with all their rhetoric of civilization is ultimately undesired by the native African inhabitants. What, you mean the native Africans don't actually want to be civilized?
Quote 98
"Good heavens! and I was going to take charge of a twopenny-half-penny river-steamboat with a penny whistle attached! It appeared, however, I was also one of the Workers, with a capital—you know. Something like an emissary of light, something like a lower sort of apostle. There had been a lot of such rot let loose in print and talk just about that time, and the excellent woman [Marlow's aunt], living right in the rush of all that humbug, got carried off her feet. She talked about "weaning those ignorant millions from their horrid ways," till, upon my word, she made me quite uncomfortable." (1.27)
Marlow finds that his aunt expects him to be something of a missionary—a man on the way to Africa to teach the native Africans—but all this talk makes Marlow uncomfortable. He knows that he's not traveling for altruistic ends.
Quote 99
[On the black slaves at the first station]: "[…] but these men could by no stretch of imagination be called enemies. They were called criminals and the outraged law, like the bursting shells, had come to them, an insoluble mystery from over the sea. All their meager breasts panted together, the violently dilated nostrils quivered, the eyes stared stonily up-hill. They passed me within six inches, without a glance, with that complete, deathlike indifference of unhappy savages." (1.36)
Ooooh, how scary: a bunch of beaten, abused slaves are such a threat that the overseers still somehow think it necessary to chain them up. But how could these men be considered dangerous enemies.