Page:Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 1.djvu/307

Rh Prognosis.—The general health is not affected. The patient chiefly complains of the disfigurement, which is very great, and of the pruritis, which in the hot season may be unbearable. The disease has no tendency to spontaneous recovery. Treatment is difficult, and cases apparently cured often show a return of the eruption after a few months.

Diagnosis.—T. imbricata, once seen, cannot be confused with any other dermatomycosis : the development in concentric rings fringed with tissue-paper like scales is absolutely characteristic.

Etiology.—The affection is caused by a trichophyton first discovered and described by Manson.

Trichophyton concentricum (Blanchard, 1901) : syn. Trichophyton mansoni (Castellani, 1905).

Description of the Fungus.—In all the cases observed by me, the morphological characters corresponded with those given by Manson, rather than with the description of later observers. The fungus is very abundant, and it grows between the epidermis and the rete Malpighi. Fresh preparations of scales in Liq. potassae show a diffuse mass of interlacing mycelium. The segments of the mycelium vary greatly in length; their breadth is between 3 and 4 microns. They are generally straight and of regular outline, without swellings or constrictions; the spores are rather large (4 to 5 microns), oval or somewhat rectangular. Aspergillar fructifications have never been observed by me, and I have never succeeded in growing the fungus. Strong very recently informed me that he also had been unable to grow the fungus in the Philippine Islands. According to Nieuwenhuis, however, the fungus may be grown on various sugar media. The latter observer states that the growth is slow and that the colonies are thick, crateriform, of a darkish colour. By inoculating the cultures in a European he reproduced the disease.