An avid fan, I’m rereading the novel to adequately attain proper levels of disgust and loathing when the movie comes out. I came across this joke I never understood. (I think perhaps it’s a Britishism.)
[Ford] helped Arthur to some peanuts. “How do you feel?” he asked him.
“Like a military academy,” said Arthur, “bits of me keep on passing out.”
At a military academy, cadets are often made to stand at attention for hours on end in the sunlight. Combined with sleep deprivation and dehydration, this sets up a scenario where cadets are very likely to topple over from a standstill with no warning.
One of two things usually causes this:
…and thump, bits of the cadet corps keep passing out.
When I first read it, many years ago, I’m sure I took as the first two replies suggest: a pun on the two senses of “passing out.” I’m quite certain Arthur doesn’t have parts graduating and leaving his body. It’s admirable that he can still make a joke in the situation he’s in. 
Ah. Thanks! 
I thought “passing out” must be some term related to marching in formation.
Mangetout has it, not Jurph. “Passing out” refers to graduating. It’s meant as a play on words, not as a reference to cadets keeling over while standing to attention. Much funnier that way.
Huh… and myself I took it as a reference to millitary cadets partying secretly in the middle of the night and drinking.
I think it’s funnier with the ‘standing at attention’ thing than classes graduating. Arthur feels like different parts of his body at different times are unable to cope with the stress and getting overwhelmed. Except he doesn’t really have ‘bits’ in the same sense as an academy does.
Mangetout
Bloody Americans - don’t appreciate a simple bit of wordplay 
Give them a break, it’s not like they speak English.
It’s a bit like being drunk.
What’s so bad about that?
Ask a glass of water.
Not in the British sense of funny, which is often “Look at this clever play on words”. I have no doubt in my mind that the “graduating” sense is what Douglas Adams had in mind for the joke, otherwise he would have written:
“How do you feel?”
“Like a student house party - bits of me keep passing out”
or something. That would have made the “passing out” sense too obvious, and ruined the “clever” humour of it.
Another good way to ruin the humour, of course, is to dissect and analyse it too much :smack:
Well, you learn something new every day. I always it assumed it referred to parades. Else why would it be a military academy? Maybe it’s because I read Catch-22 before I read Hitchhikers.
–Cliffy