What purpose does the story of the suicidal Swede serve in "Heart of Darkness"?

Question

Reading through Joseph Conrad's Heart of Darkness, I came across this paragraph, containing an anecdote about a passenger who went on to hang himself:

“I had my passage on a little sea-going steamer. Her captain was a Swede, and knowing me for a seaman, invited me on the bridge. He was a young man, lean, fair, and morose, with lanky hair and a shuffling gait. As we left the miserable little wharf, he tossed his head contemptuously at the shore. ‘Been living there?’ he asked. I said, ‘Yes.’ ‘Fine lot these government chaps—are they not?’ he went on, speaking English with great precision and considerable bitterness. ‘It is funny what some people will do for a few francs a month. I wonder what becomes of that kind when it goes upcountry?’ I said to him I expected to see that soon. ‘So-o-o!’ he exclaimed. He shuffled athwart, keeping one eye ahead vigilantly. ‘Don’t be too sure,’ he continued. ‘The other day I took up a man who hanged himself on the road. He was a Swede, too.’ ‘Hanged himself! Why, in God’s name?’ I cried. He kept on looking out watchfully. ‘Who knows? The sun too much for him, or the country perhaps.’
_{Heart of Darkness, chapter 1}

I'm a couple pages past that, and the hanged Swede doesn't seem to be mentioned again. Why, then, is this story brought up? How does this contribute to the narrative?

What purpose does this setion serve in the narrative of Heart of Darkness?

Answer 1

"Heart of Darkness" describes how people from the "civilized world", i.e. European countries, decide to go to Africa to bring "civilization" to the people there and how they fail. They end up exploiting the natives, thinking only of money, they become cruel, even turn to primitive rituals. The jungle, the climate, the loneliness and a lack of social control turns them into primitive beings, more primitive than the natives they intended to "civilize". During his journey, the I-narrator gets more and more disaffected, until he finally finds out that even the intelligent, gifted Kurtz has turned into a monster in the jungle.

The Swede who hanged himself perfectly fits into this pattern. He is one of those who loses his mind in the jungle, and a hint towards the end of the story, the discovery and death of Kurtz.