Did You Know?

In notes taken during a voyage to South America on HMS Beagle in the 1830s, Charles Darwin described an illness that he believed was caused by "miasma" emanating from stagnant pools of water. For him, "miasma" had the same meaning that it did when it first appeared in English in the 1600s: an emanation of a vaporous disease-causing substance. ("Miasma," by the way, comes from Greek miainein, meaning "to pollute.") But while Darwin was at sea, broader applications of "miasma" were starting to spread. Nowadays, we know germs are the source of infection, so we're more likely to use the newer, more figurative sense of "miasma," which refers to something destructive or demoralizing that surrounds or permeates.