Black hairy tongue (nigrities) is a hypertrophy which may involve all or part of the filiform papillae of the medial part of the dorsum of the tongue. It was first described by Rayer in 1835 under the termdiscolorations pigmentaires. In 1869 Raynaud reported several cases of it as a new entity and described the appearance of the tongue as a field of corn laid low by the wind. Raynaud ascribed a parasitic cause to black hairy tongue, and this theory was confirmed by Laveau, Lancereaux and Dessois between 1876 and 1878. Gallois, Richter and Fereol, on the other hand, maintained that the presence of spores and mycelium was accidental rather than etiologic. Dessois, in 1878, and Gettheil, in 1889, unsuccessfully carried out inoculation experiments on their own tongues. Rayer, in his original description in 1835, mentioned the impossibility of inoculation and stated that spores morphologically similar to those present