In the opening chapter of The Adventures of Tom Sawyer, we find Aunt Polly trying to dupe Tom into revealing that he skipped school to go for a swim. To preempt a potential line of questioning, Tom volunteers that his head is damp since he pumped some water on it earlier, presumably to cool down. Then his aunt says:
“Tom, you didn’t have to undo your shirt collar where I sewed it, to pump on your head, did you? Unbutton your jacket!”
Now it's been a few years since the 1800s, so what does this actually mean? I was trying to look online for some understanding of what type of collar and what sort of sewing is being suggested here, but I couldn't turn up anything.
Then, Tom's web of lies unravels when Sid detects that his collar is now sewed using black thread instead of the white that Aunt Polly originally sewed it with. Tom grumbles that:
She’d never noticed if it hadn’t been for Sid. Confound it! sometimes she sews it with white, and sometimes she sews it with black. I wish to gee-miny she’d stick to one or t’other—I can’t keep the run of ’em.
How would it be possible for Tom not to know what color thread the collar was originally sewed with? Assuming he rips off the collar, wouldn't the broken pieces of thread be more than enough to tell? I guess this goes back to the question of how this sewing of the collar is done in the first place.