The stiff upper lip and jaw of Ralph Bates finally come into their own in this nice variation of Jekyll and Hyde, which also mixes in good quantities of Jack the Ripper myth and the famous 17th century grave robbers Burke and Hare. Considerably less stiff is Martine Beswick as the doctor's female alter ego. She is absolutely too loose in her ways, but I am certainly not complaining! Both are just the right persons for their clashing roles and superbly so. The actual physical change between the two supreme parts in one person is shown in subtle manners and without great special effects, which not only was cheaper to do, but also leaves a lot for a viewer to imagine and so makes it in a way easier to accept. A wise decision from the makers.
The plot idea of unifying the two main story lines of such classic origins is nothing short of brilliant. The invention of elixir of human life using female hormones and how to get it by "uncanny goings in late hours" really does the trick. So does the fascinating and at the same time foul results of the experiment, the mixing of selves and struggle for dominance. Of course much more could have been built in and deepened in the script making the story more intriguing and disturbing. Some needed romantic and freshening humor aspect comes from the continuously snooping neighbors with their funnily pretentious "it doesn't concern us" attitude.
In all, this is once again a fun and stylish horror movie from Hammer studios. The bolder style of company's early seventies film is very much present with some slight gore and nudity added in the proceedings. So, now everyone hurry up and see it.
