Re: @dkjd Medical doctor (GP) not a scientist?
My understanding was - when a Doctor completes their initial education, they have the Bachelor of Medicine or Bachelor of Surgery degrees. They can then go out to be a GP or whatever. They can then go on to get further education - usually done while working - to become an MD.
If they decide to specialise, doing Research to cure cancer etc via a PhD program, they have to renounce the Doctor title in the medical sense, as they are no longer a general Doctor, they aren't keeping up to date in the wide field of general medicine - hence why if you are really screwed illness wise, you suddenly start meeting very highly paid specialist consultants with the title Mr...
To further muddy the waters though, there are a lot of surgeons who as members of the RCS are referred to as Mr...
Short version, if you're in hospital, and you suddenly start being seen by medical professionals who aren't surgeons but are being called Mr, you're probably very ill...