The third collaboration for Karloff and Lugosi sees a move away from Poe and into the realm of the science fiction serial. Karloff plays Dr. Janos Rukh, creator of a device that can capture light rays through his telescope in the Carpathian Mountains and translate them into pictures that form a visual history of the universe.<br /><br />Before several guests, including Lugosi as Dr. Benet, an astro-chemist who had previously scoffed at Rukh's theories, he demonstrates the existence of an unknown radioactive element, here termed "Radium X", contained in a meteor that fell to Earth in darkest Africa several thousand years ago. Karloff joins the expedition to prove his theories, but Radium X is a tricky compound - it levels mountains at long range, and cures blindness at short range. Rukh is careless, however, and poisons himself, glowing in the dark rather like those old Ready Breck commercials! Dr. Benet is on hand to devise a counter-active for the radiation, but combination of poison and cure drives Rukh insanely paranoid. Convinced he has been cheated, he seeks out the members of the expedition in Paris, including his estranged wife, and his very touch while in his radioactive state means death...<br /><br />Along the way we get the old pseudo-scientific idea that a dead person's eyes record the image of their killer (a remarkably distinct Karloff!) and the Radium X device used to symbolically melt statues that represent the expedition members. And even a touch of James Whale in a cockney landlady in Paris!<br /><br />The Invisible Ray is great fun, aside from the Gothic opening it's interesting to see Universal move the action around to Africa and Paris. The film lacks pace, but is always absorbing. Karloff slightly overdoes his performance but Lugosi is terrific. Universal used the basic story outline again in Man Made Monster, this time with Lon Chaney Jr. as the glowing menace (this time caused by electricity) and Lionel Atwill as a much madder doctor than Lugosi is here. The Invisible Ray is a sombre and clever little film with much to admire. Not as famous as other Universal Horrors, perhaps, but it works and is highly entertaining.