The Crime of Doctor Crespi (1935)

Dr. Crespi has a festering hatred for Dr. Stephen Ross, the man who married his ex-sweetheart. Ross must undergo surgery and Crespi, sensing an opportunity, seizes it. Ross "appears" to die but Crespi has given him a drug that places the victim in a trance-like state, but leaves him in possession of his senses. Crespi attends the premature burial of his hated colleague. Dr. John Arnold has his suspicions and calls on Dr. Thomas to to help him. They exhume the body and find Ross alive, albeit now a terrified, ghostly figure given to stalking the hospital corridors.