This piece was probably written for the autobiography that Wilder never finished, and it's not clear to me that these pages are themselves finished. But they are fascinating.
The notes to this page tell the bare-bones of the story: the Wilders traveled to China, where Papa Wilder was a consul, and Baby Wilder (well, one of the many Wilders) got sent to boarding school in China. So not only is Wilder facing the culture shock of China, he's facing the culture shock of English-style boarding school.
From a narrative stance, there's a great character structure here with semi-outsider Thornton not-really-befriending an American who is an outsider in the school (in his way--there's really no bullying here, which is a huge change in boarding school stories from today, I think) but also an insider in his own way with Chinese culture: his main goal is to escape the school for a night and go into the Chinese area of the city. There's hints of his adaptation to China, as when he prizes a gift from his Chinese nanny and speaks Chinese to an old man visiting a graveyard. Otherwise, the boy simply says that he wants to get into town to make money.
As a story, there's also an interesting format that I think Wilder gets away with only because of the semi-memoiristic nature of the piece: the first section is all about China, told from several different POVs telling their stories about how it's great to be a rich European in China and terrible to be Chinese because of all the famine, etc. There's also some psychologizing of the Chinese: they are so multitudinous (like locusts or stars) that they are indifferent to the life of a single person. Considering that Wilder is writing this in the 1960s, the fact that he sounds like McNamara talking about the inscrutable Vietnamese is an unfortunate coincidence.
But once we get past the world-building, the set-up of nested culture-shocks is very interesting: Wilder isn't just shocked by Englishness and Chineseness but even by some types of Americanness, as for instance the Tennesseans who are hard to understand. And the position of an old man looking back on his youth gives the Wilder-narrator the authority to very rarely dip in with some post-incident knowledge, as when he describes a boy's smile--both what he thought then and what he knows now:
At first it seemed to have nothing behind it except brazen impertinence. I wrote in my journal that it was like the reflection of a winter sun on a sheet of polished tin. I was to understand later that it was a mask to conceal despair.
There's no real end to this piece; and the front-loaded world-building would get this tossed out of many science fiction/fantasy slush-piles that would read this as pure story. But the story is very interesting when we finally get to it; and the story even allows for some interesting general comments, as when the narrator notes the war between students and masters in the school, and their shifting sense of what constitutes fair play.