"Effluvia have an emotional charge that makes them figure prominently in voodoo, sorcery, and other kinds of sympathetic magic. People in many cultures believe that a person can be harmed by mutilating or casting spells on his feces, saliva, blood, nails, and hair, and that a person can be protected from harm if those substances are cursed, buried, drowned, or otherwise ostentatiously discarded. The potency of these substances is people's minds also leads them to be used in medicines or charms, often in homeopathic or purified doses. The emotion of disgust and the psychology of sympathetic magic are entwined. The psychologists Paul Rozin and April Fallon have shown that modern Westerners respect the laws of voodoo in their own disgust reactions, such as recoiling from an object if it merely looks like a disgusting substance or has been in contact with one in the past. Word magic simply extends this chain of associations by one link, and gives the words for effluvia a dreadful power as well." (The Stuff of Thought, p. 345)
