The Good Old Days

"Our old cat was the pet of the family.  When we resided in Rochester, on the banks of the Genesee, one winter Pussy began to grow cross, and for some unaccountable reason, her good natured fits became small by degrees and beautifully less, until we were in danger of getting roundly scratched if we meddled with her ladyship in the least.  My mother finally induced me to part with my pet, and the boys carried her in a bag to the bridge which spanned the Genesee, just above the falls. They "let the cat out of the bag," and saw her take the perilous descent over the fall...."   from "The American Agriculturist,"  June, 1862    So that's where that term comes from--those idioms are literal after all.