Friday Hair Metal: Still of the Night

I bought Whitesnake's Greatest Hits this week, and it's easily the best $7.99 I've ever spent.  But I've been wondering ever since what instrument these guys are using for the bridge in the middle of the song.  You know the one I'm talking about.

I mean, they're obviously playing something with a bow.  For the longest time I thought it was a bass, but if you listen closely you can hear a bass-line underneath that bowed section, so... what is it?  Electric cello?  I really want to know.  It's been driving me crazy.

So here's a live version of the song.  Let's hope we can see what these guys are doing.

Bah!  It's a cool version of the song, but the rhythm guitarist plays the bridge in question as a series of three-string power cords using a filter.  That's not what they did in the studio.  Dammit.