The Ape is a 1940 American horror film directed by William Nigh. The film is based on Adam Hull Shirk's play The Ape, which was previously adapted by Nigh as The House of Mystery (1934). The film stars Boris Karloff as Dr. Bernard Adrian who is seeking to cure a young woman's polio through experiments involving spinal fluid. Meanwhile, a vicious ape has been terrorising the towns locals, and breaking into Adrian's lab. A battle ensues between the two leading to Adrian deciding to skin the ape and disguise himself as the beast in order to get more spinal fluid which was destroyed in the battle.

Plot

Dr. Bernard Adrian is a kindly scientist who was forced to become a small town physician after the medical community rejected his theories. He persists however in pursuing his experiments on nerve regeneration and becomes determined to cure local girl Frances Clifford's polio induced paralysis so she can eventually marry her sweetheart Danny Foster. After much work the doctor determines that all he needs is spinal fluid from another human to complete the formula for his experimental serum. Meanwhile, a vicious circus ape named Nabu mortally wounds his handler before breaking out of his cage and terrorizing the townspeople. After some time on the lamb the ape eventually breaks into Dr. Adrian's lab. The Doctor manages to kill it before any harm can come to himself. However, all the vials of the spinal fluids he requires to perform his experiments are destroyed during the struggle between him and the Ape.