Unfortunately I don’t have the full-length version (i.e. the Severin DVD release illustrating this post), just the markedly shorter public domain version that circulates on Youtube and Archive.org (where I downloaded the copy I watched this evening). I did find one source on Youtube for the full-length version, but it was only in Italian and not subtitled, which is fairly useless to me… The English dubbing is fairly useless too, albeit in a different way, but on the upside (?) at least Barbara Steele got to use her own voice in the English version, which she apparently rarely got to do in her Italian-made films. Director Mario Caiano was apparently a bit of a devotee of gothic literature, and I see the word “gothic” mentioned in relation to this film quite a lot; certainly the film gives the impression of trying to emulate Mario Bava—whose Black Sunday is, of course, the very model of the filmic equivalent to the gothic novel—without ever actually succeeding in doing so. The plot is melodramatic enough, and comparatively convoluted for something with so few characters: a scientist kills his wife after finding her cavorting with her lover the groundskeeper, but she’s left her fortune to her sister, who has mental problems, so the good doctor marries her with the intentions of driving her mad to get at the money so he can continue his experiments in rejuvenating his lover. And then there’s the ghost of the dead woman as well… Despite all this plot activity, the film actually does kind of sag a bit, though I do wonder if the pacing issues are due to the film having had chunks cut from it for its first American release (although the full-length version was fully dubbed in English, distributors at the time settled for a version that lost about 25 minutes). Going to look out for the Severin disc, which should at least be a more watchable viewing experience; I must admit to finding the version I watched (linked above) hard to appraise properly.
UPDATE (9/4/2015): So I got the Severin disc, watched it tonight, and can’t really say that my opinion of the film has changed that much; the dubbing is still meh and it still sags like hell, and it really is too long for its own good. I did, however, come away with a different appreciation for the look of the film, which is quite extraordinary, and, according to director Caiano in the DVD interview, resulted largely from the film’s low budget; he couldn’t afford colour shooting, and his cameraman only had limited lighting, but it wound up being perfect for this black and white gothic tale. It’s a better-looking film (if not, unfortunately, an actually better film) in Severin’s presentation than it is in the public domain versions you can find online.