Dr. Cyclops 1940

In his primitive laboratory somewhere in the Peruvian jungle, a mad scientist named Dr. Alexander Thorkel, Albert Dekker, pursues a radical plan to shrink humanity in order to reduce its impact on the environment. He summons a team of expert biologists from America to examine a specimen under his microscope, since his eyesight is too poor for him to do so himself. One of them identifies iron crystal contamination, a finding that seems to please him. He thanks them for their services and asks them to leave. Annoyed that they have traveled thousands of miles for nothing, the scientists set up camp in Thorkel’s stockade. There, they discover the area is rich with pitchblende, an ore of uranium and radium. Thorkel reveals that he is shrinking living creatures, using radiation piped in from a radium deposit down a deep shaft. He invites the biologists to observe his apparatus, then locks them inside his radiation chamber, where they are shrunk to twelve inches in height.

Later, when Thorkel discovers their shrunken state is only temporary, he grows angry and suffocates one of them. The rest flee into the jungle, and he sets out to hunt them so they cannot report him to the authorities. After he shoots one of them, the others hide in one of Thorkel’s specimen cases and are brought back undetected to his lab. There, they conspire to kill Thorkel with his own shotgun when he lies down on his bed. Instead, he falls asleep at his desk. They do manage to smash one lens of his glasses before he awakens. Thorkel chases the shrunken group to the mineshaft and is left hanging by a rope when a plank he is lying on breaks. One of them cuts the rope, and Thorkel plunges to his death. In time, the survivors are restored to their original size and begin their trek back to America.