DR RENAULT'S SECRET: the last two letters are silent

The secret no one ever discovers is that the L and T in Dr Renault's name are silent. Not even Dr Renault knows it for he never corrects the villagers when they insist on calling him Dr Ren-alt instead of Dr Ren-O.

However, it's the other secret that everyone involved in this low budget horror is more concerned about - who or what is Noel, the doctor's strangely simian servant, and why does he have tissue paper stuffed under his upper lip?

There's nothing particularly original about this 1942 b-movie from 20th Century Fox.but it still succeeds in being reasonably entertaining. The Doctor (the wonderful George Zucco) lives in a stately chateau in a small French village, tended to by Noel (J.Carrol Naish), who dotes on the Doctor's attractive young niece Madelon.(Lynne Roberts). Madelon is engaged to Larry Forbes (Shepperd Strudwick), a young doctor with a disturbingly prominent overbite, who shares his future father-in-law's fascination with the workings of the human brain. 
Dr Forbes arrival in the village to visit Madelon is the trigger for a series of increasingly brutal murders - but who is to blame? Is it the socially awkward Noel or Dr Renault's burly gardener Ragell (played by Mike Mazurki as the least convincing Frenchman in history)?
The fun to be had here is not only in watching the cast taking this patent nonsense with deadly seriousness, but also in the low - very low - production values. These include not spending any money on a continuity girl (who would ensure shots matched up) or on re-taking shots where the action wasn't quite right. The most glaring example of this is the scene where a villager has been attacked and knocked out by the 'monster' who then picks him up to throw him through a window. The 'monster's' a little on the short side and  clearly struggling to lift his victim off the floor so the unconscious man very obviously puts his arm around the monster's neck to help.
All this in less than an hour!
DR RENAULT'S SECRET is creaky, cheap, cliched and corny. It's the kind of product one would have expected from Monogram rather than a studio of Fox's status. But it's also undeniably charming in a creaky, cheap, cliched and corny kind of way.