This film was by all means a head of its times with heart transplants and mechanical parts in the year 1939. This films success was encouraged by a Dr. Robert Cornish who was a biochemist hired by Columbia pictures who present the idea of a mechanical heart. Columbia signed Karloff for several more films in the same theme, staring the actor onto his second "crazed scientist" cycle. It is unbelievable that for more than twenty-five years later, human lives were successfully prolonged by surgical heart transplants. Karloff looks less menacing that he has been in the past. Karloff as usual, turns in his usual good performance.