A desperate search for a marauding ape and a cure for polio

Released 30 September 1940, The Ape was Boris Karloff’s final film in his six-picture contract with Poverty Row studio Monogram. Despite the studio’s low-budget profile, this film was one of their “top bracket productions” for the 1940–41 cinematic year.

The Ape was based on Adam Hull Shirk’s play of the same name, which débuted in 1924 in Hollywood. The play earned high praise, and was compared to horror film classics The Bat and The Cat and the Canary, Ralph Spence’s play The Gorilla (which was made into several films), and Rudyard Kipling’s short story “The Mark of the Beast.”

In the source material, there’s a prologue in India, depicting a Hindu priest putting a curse on an Englishman who killed a sacred ape. Thirty years later, the Englishman is sent to L.A. to be taken care of by his family, since he’s such a hot mess.

Monogram filmed the play as House of Mystery in 1934, then remade it in 1940 with barely any similarities.

The Los Angeles Times praised the film as engrossing, and Karloff as “the skilled player of slightly eerie but really kindly character roles for which he is famous.”

In a 2015 essay for the British Film Institute, curator Vic Pratt named The Ape as one of Karloff’s ten essential films.

The circus is coming to the small, insular town of Red Creek, which greatly excites four boys who can’t stay away from trouble. After they watch a circus poster going up and excitedly talk about the coming wonders, they decide to go swimming.

On the way there, they pass Dr. Bernard Adrian’s house and begin throwing rocks at his windows. They succeed in breaking some, which greatly upsets Dr. Adrian when he arrives home on his bike.

Almost no one in town likes or trusts Dr. Adrian, who came there ten years ago during a polio epidemic and now spends his time doing unorthodox experiments. He lost his wife and daughter to the dreaded disease, and has made it his life’s mission to find a cure.

Dr. Adrian’s sole patient is Francis Clifford (Maris Wrixon), a young woman who was stricken by polio during the epidemic and now lives in a wheelchair. He feels a special connection to Frances because he lost his own daughter to polio, and doesn’t want anyone in the world to ever suffer such a dreaded disease again.

Though Francis and her mother have faith in Dr. Adrian’s promises of walking again, Francis’s beau Danny is very suspicious. He outright admits he doesn’t like or trust what he doesn’t understand.

That evening, Francis and Danny go to the circus. Though Francis wants Dr. Adrian to come too, he begs off and says his experiments to find a cure are too important to ignore.

Francis is captivated by a female aerialist, and dreams of someday being that mobile and coordinated.

After the circus adjourns, ape Nabu (an obvious person in a gorilla suit) turns on his cruel trainer, whose brother he killed prior. One of the other circus employees rightly points out to the indignant trainer that apes, or any animals, only become so vicious in response to repeated abuse. He wouldn’t act like that if he were treated kindly.

Nabu breaks out of his cage and attacks the trainer when they’re alone, and starts a fire with the trainer’s cigar. During the ensuing panic and commotion, Nabu flees.

The injured trainer is taken to Dr. Adrian, who’s unable to save him. However, the trainer proves very useful to Dr. Adrian’s experiments. Never before has he had spinal fluid from a human subject, something he believes is the key to curing polio.

Dr. Adrian begins giving Francis the injections the very next day, and they seem to have immediate effect. Though Francis has great pains in her legs and finds them like lead weights, this is huge progress. For someone who had no feeling in her legs for ten years, any sensation is positive.

That night, Nabu breaks into Dr. Adrian’s house and attacks him, and here the plot thickens. As the search for Nabu continues, suspicions begin piling up that he’s near Dr. Adrian’s house. More spinal serum is also desperately needed after Nabu destroyed the originals, and another tube accidentally rolled onto the floor and broke.

But no matter what happens, Dr. Adrian is bound and determined to fully cure Francis, both mind and body.