About gall stones

I remember a while back being recommended to watch a movie by someone
on this group. It was about a doctor around the turn of the century
who discovered or developed something from working with horses (was it
a cure for cancer?) and then the British Medical Association was
formed and he wasn’t allowed to practice medicine and ended up with a
clinic in Mexico. I seem to remember the DVD was in black and white.
Does anyone know what I’m talking about?
Tina