Basil Rathbone is sublime, Nigel Bruce is good but a little theatrical, some of the minor actors are pretty poor. The overall effect is uplifting and makes you want to go and solve some crimes straight away. I think my English is improved for it too. I believe it is a shame there is so little like this now, heroes now have to be superheroes who can fly. I do not think this is better. There is plenty of scope for escapism in a character like Sherlock.
This is the most faithful of the Universal Sherlock Holmes series to the original stories by Arthur Conan Doyle. The premise of the Adventure of the Six Napoleons is intact, though the script elaborates to good effect. It introduces The Creeper played by Rondo Hatton, a huge actor whose features were deformed by acromegaly.
It's tragic his disfigurement meant he was cast as a human monster. But he turned it into a career and even appeared in a couple of spin offs. Someone has hidden the priceless Borgia Pearl in the bust of one of six new plaster Napoleons. The giant killer breaks the spines of all the buyers, scattering their corpses with the broken pottery.
So Sherlock Holmes investigates. Basil Rathbone complained that all his performances as the great detective were just copies of the first. But he's so perfect, that's a good thing. Nigel Bruce isn't the Dr. Watson from the page, but provides comic relief with some expertise. Miles Manders and Evelyn Ankers make excellent villains.
Ankers was frequently cast as support in Universal monster pictures, and there is a conspicuous aura of horror in this. But the big takeaway is how artfully photographed it is. It's just a B feature, but time has been spent on these lighting setups to create an attractive noir look. This is far better than it needed to be.