Q. Why a mouse when it spins?
A. The higher the farther!

Notice it's not "Why is a mouse when it spins," and the answer isn't " The higher the fewer" either. Although both of those are common variants. I'm trying to find a source of the original quotation, which I thought was Lewis Carroll, but no one can find a vetted citation. Which is the correct phrase? Does it really matter? No. But I'm curious.

If you google Why a mouse..., you will see a bunch of references, including http://www.wordwizard.com/clubhouse/founddiscuss1.asp?Num=5902, and
http://answers.google.com/answers/threadview?id=125315.
All well and good; people are trying to take the query seriously. But the trail stops there, and I'm trying to go a step or two further back...any thoughts?

This board has wide exposure - anyone out there have an answer?