Yes; the upper part of the trunk, especially anteriorly, is the usual seat of the eruption, but in exceptional instances the neck, axillae, the arms, the whole trunk, the genitocrural region and poplitea, and in rare cases even the lower part of the face, may become invaded. #What course does tinea versicolor pursue?# Persistent, but somewhat variable; as a rule, however, slowly progressive and lasting for years. #To what is tinea versicolor due?# To a vegetable fungus--the _microsporon furfur_. The affection is tolerably common, and occurs in all parts of the world. With rare exceptions, it is a disease of adults, and while looked upon as contagious, must be so to an extremely slight degree. [Illustration: Fig. 73. Microsporon Furfur x 400. (_After Duhring._) Showing mycelium in various stages of development, groups of spores and free spores.] #What is the pathology?# The fungus, consisting of mycelium and spores, the latter showing a marked tendency to aggregate, invades the superficial portion of the epidermis. #Is tinea versicolor readily diagnosticated?# Yes; if the color, peculiar characters and distribution of the eruption are kept in mind. It is not to be confounded with vitiligo, chloasma, or the macular syphiloderm. If in doubt, have recourse to the microscope. #State the method of examination for fungus.# The scrapings are taken from a patch, moistened with liquor potassae, and examined with a power of three to five hundred diameters. #State the prognosis of tinea versicolor.# With proper management the disease is readily curable. Relapses are not uncommon. [Illustration: Fig. 74. Tinea versicolor.] #What is the treatment of tinea versicolor?# It consists in daily washing with soap and hot water (and in obstinate cases with sapo viridis instead of the ordinary soap) and application of a lotion of--sulphite or hyposulphite of sodium, a drachm to the ounce; sulphurous acid, pure or diluted; carbolic acid, or resorcin, ten to twenty grains to the ounce of water and alcohol; or corrosive sublimate, one to three grains to the ounce of water. Sulphur and ammoniated-mercury ointments are also serviceable. The following used alone, simply as a soap, or in conjunction with a lotion, is often of special value:-- [Rx] Sulphur, praecip., .................... [dram]iv Saponis viridis, ..................... [dram]xii. M. After the disease is apparently cured, an occasional remedial application should be made for several months, in order to guard against the possibility of a relapse. #Erythrasma.# #Describe erythrasma.#