What is the derivation of the phrase, "The white mouse is dead?"?

Question

This phrase is typically used when one smells a particularly pungent odor. My father has been saying it for years, and he said that his father used to use it. We don't know, however, where it actually came from or what it originally meant or referred to.

Answer 1

I've heard people say " the white rabbit is dead" refering to a woman finding out that she is pregnant. Apparently, people used to inject a rabbit with a womans blood, and if the rabbit died, the woman was pregnant.