During his stay at the leper colony, Ernesto turns 24. He sees this as a big milestone, because he’s been alive for almost a quarter century, and he says that life, “all things considered, has not treated me badly.” Dr. Bresciani organizes a huge dinner and party in the colony’s dining room. Drunk on pisco, Ernesto makes a speech in which he thanks his hosts effusively and then says that all South Americans are part of “a single mestizo race” and that divisions between countries are false. He makes a toast to Peru and to “a United Latin America.”
The birthday is a turning point in Ernesto’s life, marking the end of his youth and the beginning of a more mature adulthood. This maturity is evident in the speech he makes, which doesn’t focus on himself but expresses his nascent political ideology. It’s notable that this milestone occurs at the leper colony, which is a microcosm of his ideal society. Seeing the equality of people at the colony has inspired him to speak publicly about politics for the first time.
The next day, accompanied by the doctors, Ernesto and Alberto visit a local Indian tribe, the Yaguas. He notes that their way of life combines traditional practices (like the way they construct their huts) with modern influences (like European clothes).
The Yaguas manage to adapt to the modern world while preserving their ancient customs. They are an example of how South American societies could function in the world while limiting foreign influences and maintaining the unique identity of their indigenous people.
After enjoying the hospitality of the colony for a few more days, Ernesto and Alberto prepare to depart. They build a raft on which they plan to sail further down the river. The colony throws them another huge party. The patients cobble together a small orchestra and anxiously give speeches thanking the young doctors for their visit. Alberto also starts giving a speech, but becomes too emotional to finish it. The next day, everyone watches while Ernesto and Alberto cast off down the river in their improvised raft.
Ernesto has achieved his original goal of visiting a leper colony, but he learned different things from what he expected to learn. Instead of confirming his aspirations as a doctor, the colony has solidified and allowed him to express his new commitment to political activism. That he and Alberto depart the colony in a highly unorthodox manner highlights the fact that their lives are also diverging from the conventional paths they had planned.