Symbolism, Imagery, Allegory
You know all about representative government from social studies class, but you might not know about representative mourning. In Out of Africa, when something bad happens, according to Dinesen, the Natives let one person stand in for and experience their pain, like a senator or state representative stands in for her constituents.
Dinesen calls that representative a brass-serpent, in reference to the Nehushtan, a symbol from the Bible. The New Testament, John 3:14-15 to be exact, says that Jesus would be lifted up like the serpent was in the desert. And that's a reference to Numbers 21:4-9, which is where the brass serpent was lifted up so that people who looked at it could be cured. Wait, what?
Let's break it down. Jesus is considered to be the scapegoat for humanity in Christianity, a religion which Dinesen lightly adheres to. So that means that he is sacrificed for everybody. The brass serpent, too, was sort of like a lightning rod for sickness, taking all the disease in so the people could be cured. Which brings us to Africa, finally.
The Baroness claims that the Natives would be really worked up about something until they had a brass-serpent to let it all fall on, which freed them up to go about their ordinary lives. So, for example, when a pest of grasshoppers comes to ruin all the crops, everybody's in a tizzy until they find out that Lord Delamere is upset too:
Their hearts broke, they panted, or howled like dying dogs, they ran their heads against a wall in the air before them. I then happened to tell them how I had driven through Delamere's farm and had seen the hoppers on it, all over the place, in his paddocks and on his grazing land, and I added that Delamere had been in great rage and despair about them. At that same moment the listeners became quiet and almost at ease. (2.2.26)
The Natives have found their brass-serpent, so they can let him suffer in their place. Dinesen tries to explain it:
They can turn you into a symbol. I was well aware of the process, and for my own use I had a word for it—in my mind I called it that they were brass-serpenting me. (2.2.24)
And the Baroness herself uses the method, using her brother's direct experience in the war as a brass serpent to ease her own anxiety.
The brass serpent image comes from the Judeo-Christian tradition, but Dinesen applies it to African culture, as though she's trying to find something in common between the different religions and beliefs.