Why Famous: Founded the discipline of toxicology. Also known as a revolutionary for insisting upon using observations of nature, rather than looking to ancient texts, in open and radical defiance of medical practice of his day. Credited for giving zinc its name, calling it zincum. Modern psychology often also credits him for being the first to note that some diseases are rooted in psychological illness.
- "Consider that we should call not our brother a fool, since we know not ourselves what we are."