Sentence:  ... Paracelsus and some few other sooty <WSD>Empiricks</WSD>, rather then (as they are fain to call themselves) Philosophers, having their eyes darken'd, and their Brains troubl'd with the smoke of their own Furnaces, began to rail at the Peripatetick Doctrine, which they were too illiterate to understand ... 
Meaning of the word marked with <WSD> tags:  Any unqualified or dishonest practitioner; a charlatan; a quack.