Karloff and Lugosi - Together again! This is one of those films that casual fans will pass over and tend not to appreciate as much. It's not an all-out horror film like the duo's previous two hits, The Black Cat and The Raven. But, it is very worthy of both's talents and is a fun film when re-visited.<br /><br />The Invisible Ray was directed by Lambert Hillyer, a director who mainly made westerns, but curiously in these final days of the Laemmles' reign at Universal, he found himself helming this and the Laemmles' final horror film, Dracula's Daughter. Both are crisp, clean-cut fantasies that are very light on horror content despite the fantastic elements.<br /><br />Just as Lugosi went wild in The Raven, much needs to be said of Karloff's hamming in The Invisible Ray. The one aspect of the story that is particularly unsatisfying is that Karloff's character, Rukh, acts so madly before he is poisoned by Radium X, that there really isn't much of a change once he starts glowing. This is very similar to the complaint people have about Jack Nicholson in The Shining - He's basically a loony right from the start. There isn't any real transformation. Same here. Halfway through Karloff simply has an added purpose for revenge in his mind. I still enjoyed his performance, though, just as I did Lugosi's over-the-top antics in The Raven.<br /><br />Meanwhile, Lugosi completely surprises you and gives a restrained, and thoughtful turn as Rukh's rival in science, Dr. Benet. Lugosi also has some of the best lines in the film, including a memorable warning to the police trying to catch Rukh, of which I am in alignment with horror film writer John Soister on - "And if he (Rukh) touches anyone?" the inspector inquires. Lugosi hesitatingly replies, in a way that only Lugosi could deliver, "They die". Just as Lugosi could be so off, he could also be more perfect than any actor. This is one of those moments.<br /><br />Therefore, Karloff and Lugosi's interactions are all very good as we get the mad antics of Karloff pared off against the cool logic of Lugosi. Karloff would go on to play similar mad scientists many times, however, one wishes Lugosi would have gotten to play more straight roles like this one. He only had one more chance (Ninotchka).<br /><br />The Invisible Ray is a fun film, and a real treat to the true Karloff and Lugosi fans. It is one of those films that improves on each viewing, not because it is a masterpiece, but because of the charisma and talent of its' stars and how this story complements the darker, more horrific pairings they had. The special effects, by the always innovative John Fulton, are terrific and the supporting actors are all adequate. Frances Drake looks as beautiful as she did in Mad Love and plays a strong woman, something seldom seen in classic horror films. The scene in the end when Karloff stalks her and she doesn't scream is one of the most haunting moments of the film. A terrific, fun film!