The nails, like any other epidermic tissue, are exposed to the invasion of the trichophyton, yet cases of the kind occur rather rarely. Saubouraud, in the department of the ringworm affections in the Hospital St. Louis, considers onychomycosis trichophytina a rare disease. Neuberger1 referred to the fact that Anderson, in Glasgow, among 11,000 cases of cutaneous diseases, of which 178 were of trichophytic nature, did not have a single case of trichophyties of the nails. White, of Boston, in 5,000 cases of diseases of the skin, with 180 cases of tinea trichophytina, did not have one case of trichophytic onychomycosis. On the other hand, Pellizzari, Arnozan, Dubruille have often seen cases of the kind, and Pick considers this affection of the nails not so rare as stated by the others.
In some cases of onychomycosis trichophytina, the origin of the fungus is clearly found as patches of herpes tonsurans in