With hindsight, mercury (which was a major component of his "cures") was an unfortunate choice, but as you said, the prevailing belief at the time in the "four

With hindsight, mercury (which was a major component of his "cures") was an unfortunate choice, but as you said, the prevailing belief at the time in the "four humors" (where you were thought to have too much or too little blood, bile, or what not if you were ill) wasn't really much better.