What is the significance of the homosexual encounter at the end of chapter II?
At the end of chapter two, Fitzgerald employs an ellipses, which effectively fastfowards the readers into the next morning. Besides the ideas of the sexual depravity of the time, why is the purpose of this segue from the general plot?
Whoa! This is a loaded question! In short, I think "the purpose of this segue" is to prove that Nick is a normal human being that has flaws and faults like the rest of us, not some superhuman Midwesterner for us to put up on the proverbial pedestal.
Ironically, I just asked about this on the discussion board last week! (I have included a link for you.) I was literally wondering if absolutely anyone would suggest what you surmise. No one responded with that idea. I found "lit24" to be incredibly helpful in that I have always neglected to remember the important quote right smack dab in the middle of the chapter:
I have been drunk just twice in my life and the second time was that afternoon, so everything that happened has a dim hazy cast over it although until after eight o'clock the apartment was full of cheerful sun.
Of course, that doesn't mean that nothing "happened." Still, I do think it's something quite "normal" when someone is truly "wasted," you know? Although, I don't suppose a homosexual encounter would be out of the question either. Ha! In my opinion, the ellipses you speak of are the lapses in and out of consciousness from Nick's drunken stupor. To use Nick's own words, . . . the ellipses are his "dim hazy cast" that he refers to above.
Your guess is as good as mine in regards to what happened during those ellipses. I suppose only Fitzgerald truly knows.