For other uses, see Eidolon. In ancient Greek literature, an eidolon (plural: eidola or eidolons) (Greek Îµá¼´Î´ÏÎ»Î¿Î½: image, idol, double, apparition, phantom, ghost) is a spirit-image of a living or dead person; a shade or phantom look-alike of the human form. The concept of Helen of Troy's eidolon was explored both by Homer and Euripides.
Black hairy tongue is caused by bacteria or fungi in the mouth, which make the tongue appear black and hairy. It's easily remedied by good old-fashioned oral hygiene. A black hairy tongue is caused by too much bacteria or yeast growth in the mouth. The bacteria build up on tiny rounded projections called papillae. These lie along the surface of the tongue. Instead of shedding as they normally do, the papillae start to grow and lengthen, creating hair-like projections.
A black or brown tongue typically is due to the overgrowth of bacteria that normally are present on the tongue. This, too, can be caused by the killing of some bacteria with antibiotics so other bacteria overgrow. But the most common cause of discoloration of the tongue is the overgrowth of a fungus. The most common fungus is called candida. But overgrowth of the candida fungus turns the tongue white. Infection with candida is called candidiasis, and when it happens on the tongue the condition is called thrush.