Why did Miss Muffet drop her curds and whey?

The "Little Miss Muffet" nursery rhyme first appeared around 1805, and was composed as:

Little Miss Muffet
Sat on a tuffet,
Eating her curds and whey;
Along came a spider,
Who sat down beside her
And frightened Miss Muffet away.

"Curds and whey" being side products of the process of making cheese.

Miss Muffet was scared away by the sight of a spider next to her.