donation. 1  an act or instance of presenting something as a gift, grant, or contribution. 2  a gift, as to a fund; contribution.
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.
While dry mouth is typically the most likely cause of your white tongue, it could also result from a condition known as leukoplakia. Basically, this means the your mouth cells are overproducing, causing them to cluster on your tongue. Rather than a consistent film, people whose tongues are white from leukoplakia typically have more noticeable patches where surplus cells have gathered. These white spots can also form in other areas of your mouth.