Quote 4
[The brickmaker to Marlow]: "There was an old hippo that had the bad habit of getting out on the bank and roaming at night over the station grounds. The pilgrims used to turn out in a body and empty every rifle they could lay hands on at him. Some even had sat up o' nights for him. All this energy was wasted, though. 'That animal has a charmed life,' he said; 'but you can say this only of brutes in this country. No man - you apprehend me?—no man here bears a charmed life.'" (1.68)
In case you had any doubts about which side Nature is on, this passage should clear things up: the animals'.
Quote 5
[The brickmaker]: "'The same people who sent him [Kurtz] specially also recommended you. Oh, don't say no. I've my own eyes to trust.' Light dawned upon me. My dear aunt's influential acquaintances were producing an unexpected effect upon that young man." (1.59)
Here, we find out that the brickmaker is trying to get in good with the Company bigwigs, the friends of Marlow's aunts. And we also find out that Kurtz was recommended by the same people as Marlow. Hmmm. That's an interesting parallel.