Hormesis is a little-known term with huge implications. It refers to a fascinating phenomenon: a favorable biological reaction to low doses of chemical toxins, radiation or some other form of stress that is damaging, even fatal, in higher doses. It was first scientifically noted by German pharmacologist Hugo Schulz in 1887, who found that disinfectants -- which, in large doses, kill yeast -- actually stimulate yeast growth when administered in small doses. Of course, many had observed it anecdotally, and poetically, before that. German philosopher Friedrich Nietzsche famously observed, "What does not destroy me makes me stronger," which gets the gist, but overstates a bit -- a more precise phrasing might be, "What stresses me within certain parameters makes me better adapted."