and the fungus remains quiescent until the return of the next hot weather.
Diagnosis.— The diagnosis of mycotic dermatitis is usually easily made. The festooned margin is almost conclusive. In the case of pemphigus contagiosus the characteristic blebs, the smooth, raw, or glazed surfaces, and undermined epidermic rings are usually very apparent and render diagnosis easy. When doubt exists, recourse to the microscope may be necessary; but, owing to the inflamed condition of the parts, there may be much difficulty in finding fungus elements even when the case is certainly epiphytic. A negative result is, therefore, not always conclusive against ringworm.
I am convinced that many cases of dhobie's itch are produced by Microsporon minutissimum, and that they are really inflamed erythrasma and not trichophyton ringworm. During cold weather one often sees, on the site of what, during the summer, had been a troublesome dhobie's itch, a brownish furfuraceous discoloration of the crutch or axilla. The same appearance I have remarked in Europe in Europeans who had suffered from dhobie's itch in the East, and on examining scrapings from the parts have found M. minutissimum in abundance. It would seem, therefore, that during the heat and moisture of a tropical summer this generally very unirritating parasite becomes more active and excites dermatitis. The same may sometimes be seen in pityriasis versicolor. I believe that those cases of Microsporon— furfurand minutissimum— dhobie's itch are more easily cured than the trichophyton varieties.
Treatment. After a thorough use of soap and water, the application of Vlemingkx's solution of sulphuret of calcium (1 oz. quicklime, 2 oz. precipitated sulphur, 15 oz. water, boiled together in an earthenware vessel till reduced to 1 oz.; decant the clear sherry-coloured fluid after subsidence) every night for three or four times generally brings about a rapid cure. If the parts are inflamed and tender the solution should be diluted to half or one-quarter strength for the first two applications. A preliminary
