Professor Charles Conway (John Carradine) is a Mad Scientist attempting to develop the proverbial Fountain of Youth by creating "the 17th gland". Ignoring all aspects of scientific ethics, his research subjects are people who have no family and are under the impression that Conway can cure their depression. However, his research hasn't been successful and his subjects are turned into grotesque zombies. Some of Conway's patients begin to catch on to his scheme and intend to stop him.
- Hoist by Their Own Petard: Conway is stabbed to death by his earlier test subject Harry Jethro, who turns out to be Not Quite Dead.
- Immortality Immorality: He hasn't actually achieved it yet, but Conway keeps up his gruesome glandular experiments trying to figure it out.
- Mad Scientist: Professor Conway, of course.
- Ominous Pipe Organ: Conway treats his guest to the Toccata and Fugue on his living room Hammond.
- Public Domain Soundtrack: Several of the musical cues in this film would reappear in Bloodlust.
- Redemption Equals Death: Danny Green's first appearance is a temperamental one, abusing the other patients and Lobo. He only becomes truly sympathetic when he sacrifices himself in helping Mark escape.
- The "The" Title
- We Will Use Manual Labor in the Future: Conway has a bunch of cavemen in his basement, turning some sort of power turbine to keep his machines running. It's not made clear if they were his first failures or the source of his glands.