Slowly I turned, step by step, inch by inch...Huh?

Factual Questions
1

"Slowly I turned, step by step, inch by inch…

Okay, I know you’ve all heard someone say this, usually in a sitcom, in any sort of given situation, usually with something scary or mysterious happening, or when someone is trying to reenact a mystery. I don’t know if they ever get beyond the “inch by inch” part.

What is the origin of this phrase?

2

http://www.niagarafallsreporter.com/slowly.html

3

The “Slowwwly I turned” routine was also discussed in this thread.
http://boards.straightdope.com/sdmb/showthread.php?threadid=37531

4

Vaudville, huh? I shoulda guessed.
Okay, thanks!