The alkaloid atropine occurs naturally in plants like deadly nightshade, datura, and henbane. It can keep your heart rate steady after a heart attack, dilate your eyes - think belladonna - or dry up secretions during surgery. Soldiers carry atropine injectors because it's an antidote to nerve gas. But in high doses, it's hallucinogenic and poisonous. Remember the three fates of Greek mythology? One of them, Atropos, determined the mechanism of death for mortals. Atropine is named for her.