Fervishly??

I notice this word in books a lot, often mistaking it for the word "feverishly". I wonder what it means. But the story goes on, and I forget to look it up. Until a few days ago.
I used my Meriam Webster dictionary app on my iPod Touch. And... no results. I was confused. I decided to look it up on the internet when I got a chance. Naturally, I didn't remember to until now. The stupid Google search bar decided I meant "feverishly". NO. I meant "fervishly". Why would I write "feverishly or feverishly"????? Anyway, here are my results:

This is when I noticed.

Whoa. Fervishly is like, not a word. Like, literally. WHAT. I have seen it in at least 50 books! Hm.