On the witness stand, Dr. Savaard claims that one day it will be possible to take a heart from a person, such as someone killed in an automobile accident, and place it into the body of a person in need of a new heart, while skeptics in the courtroom scoff. Twenty-three years later, on December 3, 1967, the first successful human heart transplant occurred at Groote Schuur Hospital in Cape Town, South Africa. The patient, Louis Washkansky, received the heart of a young woman tragically killed in an automobile accident.
Dr. Savaard's monologue about how medically inducing death would help surgeons treat patients without racing against the clock, predicts the rationale behind medically induced comas that have been used since the 1960s. The basic idea is to induce a body into a reversible coma to slow everything down to a near stop so the body can reduce the amount of energy needed and use all of its energy for healing.
A photo of Boris Karloff as character Dr. Henryk Savaard was used 2 years later as a background image on a lobby card for Más allá de la tumba (1941).
Shooting lasted from June 27-July 12, 1939, released Aug. 17.
This movie incorporates plot elements found in the film it references, "The 9th Guest" (1934) and the novel that film is based upon,
"The Invisible Host", by the husband-and wife team Gwen Bristow and Bruce Manning.