Common fungus infections of the skin.

I. Ringworm fungi. This is a very large class, but we need refer only to the following types:(a) Microspora. (b) Trichophyta. (c) Achoria. (d) Epidermophyta. The microspora have small spores in mosaic arrangement, and are found in profusion on the hair surface. They are responsible for most of the scalp ringworm in this country, and are ,either conveyed by human infection (M. audouini-the largest group), or from animals (M. lanosum). Infection with M. audouini tends to -die out at puberty, and only occasionally attacks the glabrous skin. Infection with M. lanosum generally shows more reaction, and on the glabrous skin cause well-marked rings. The trichophyta are large-spored ringworm, and are divided into two groups, the endothrix and the ectothrix. The endothrix group are of human origin and grow in large-spored chains within the hair, but the ectothrix group, of animal origin, grow on the hair surface and within the hair as well. The trichophyta also attack the glabrous skin, beard and nails, and produce a vigorous reaction, frequently going on to pustulation. The Achoria are responsible for the production of favus, characterized by the occurrence of yellowish, cup-shaped scutula. It commonly affects the scalp, but may affect the hair, glabrous skin or nails. The usual organism is A. Schonleini, but the group is nowadays usually placed in the endothrix trichophyta.' The epidermophyta never affect the hair. They are commonly responsible (especially the E. inguinale) for infection of the crural region (Tinea cruris or Dhobie Itch), between the toes and in the nails.