Watched this last night.
And what a special FX tour-de-force it is! Laser beams, glowing men, fizzing rocks, spontaneous combustion! It had it all. Add a trip to Africa and a wonderful gothic opening into the mix, and you have yet another classic Universal film.
This is included in the Bela Lugosi box set in R1, but let's face it, it's a Karloff film really - Lugosi is relegated to secondary status. Still, he's good in it, and just to see Karloff with that somewhat silly mop of curly hair is easily enough to justify the film.
I really enjoyed this, yet another wonderful slice of entertainment.