This painfully-bad Monogram feature wastes the talents of two of horrordoms finest -- star Boris Karloff and co-writer Curt Siodmak (who would write the horror classic The Wolf Man for Universal the same year). The goofy plot involves the efforts of one Dr. Adrian (Karloff) to procure human spinal fluid for his polio-vaccine research by donning the pelt of a slain circus ape and slaughtering innocent people. The fact that hes snapping spines in the interest of medicine doesnt really help to clear the moral waters (he never does find a cure, anyway). Filmed during a particularly grueling year for Karloff, this marks the end of his lengthy stir with Monogram (after a tedious string of Mr. Wong potboilers). Without Karloff to kick around, the studio concentrated their humiliating efforts on Bela Lugosi, who appeared in a virtual remake, The Ape Man, three years later. ~ Cavett Binion, All Movie Guide