> in the first story in Grimm's Fairy Tales
It's the second story. The first is the "frog prince".
> The cat then proceeds to eat the mouse.
Even the english Wikipedia article does not mention the most important part:
When she beholds the empty pot, enlightenment dawns on the mouse: "First 'Top-off,' " she murmurs, "then 'Half-gone,' and then ..." The cat warns her to say no more, but the mouse persists. The cat pounces on the mouse and eats her up.
The mouse says "All-gone" and is than eaten because of that. And the first version does not contain the phrase
"And that is the way of the world," the story closes.