RINGWORM is a popular term for several distinct forms of skin-disease which occur in patches of a circular or annular form on the body, and especially on the scalp. Thus, a species of lichen (q.v.), known to dermatologists as lichencireumscriptus, in which the papules assume a circular arrangement, is commonly regarded as ringworm; and the two species of herpes (q.v.), known as herpes cireinatus and M. iris, in which the vesi cles occur in circular patches and in concentric rings, are usually included in the same term. None of these are, however, cases of true ringworm (tinea ton dens), which is a disease dependent on the presence 9f a, special vegetable (fungous) parasite, now known to botanists as the trichophyton tonsurans, or hair-plant, and discovered in 1845 by Malm sten. It consists of oval transparent spores or globules, about of an in. in diam eter, for the most part isolated, but sometimes connected by articulated filaments. This fungus is seated in the interior of the hair-roots, and the hairs and the fungi simul taneously increase in size. The diseased hairs lose their elasticity and break when they have risen a line or two above the scalp. In these cases the short stump of hair soon loses all its characteristics. If the hair breaks before emerging from the scalp, a little prominence isformed, consisting of fungus.epidermis,and sebaceous matter, and the assem blage of such /tale prominences gives the scalp the rough appearance known as goose skin. This parasite exists, according to Dr. Aitken—whose Science and Practice of Xed icine contains an excellent abstract of all that is known regarding parasitic diseases—" in the herpes tonsurans of Cazenave, which is the porrigo scutulata of Willan, the liners tonsurans of Bazin, and the trichosis ,fulfurans of Erasmus Wilson and Dr. Wood." There are three varieties 'of true ringworm, which are described by Aitken under the following names: 1. Ringworm of the body ((Inca cirmnatus); 2. Ringworm of the scalp (tinea tonsurans); and 3. Ringworm of the beard (tinca sycosis).
1. Ringworm cf the body first appears as a rose-colored and slightly elevated spot about the size of a fourpenuy-piece, on which a bran-like desquamation of epidermis soon begins, accompanied by slight itching. This spot gradually increases in size, but
retains its circular form; and as it extends, the healing process commences at the center, so that the circular red patch is converted into a inclosing a portion of healthy skin; and a ring thus formed may continue to increase till it reaches a diameter of four in., or even more. It is apt to affect the face, the neck, the back, and the outside of the wrist. This form of ringworm frequently terminates spontaneously.
2. Ringworm of the scalp usually occurs in children, and is especially prevalent when the nutrition is defective, or there is a scrofulous mint in the constitution. It appears in the form of round, scaly, irritable patches on different parts of the head; and the irrita tion often occasions the formation of minute vesicles. The hairs at these spots become dry and twisted, and are easily extracted; and when the disease advances, they break close to the scalp if an attempt is made to extract them. The stumps, and the epider mis surrounding them, become covered with a characteristic grayish-white powder, con sisting of the sporules of the fungus. The diseased parts are slightly elevated and puffy, and differ from the healthy scalp in color, being bluish or slate-colored in dark persons, and grayish-red or yellow iu fair patients. The inflammation will last as long as the growth of the fungi continues; and even when they die spontaneously, as sometimes occurs, the affected spots remain permanently bald, in consequcuce of the hair-bulbs having become obliterated.
3. Ringworm of the beard is chiefly met with on the chin,lairy part of the cheeks, and upper lips of men; but it occasionally attacks the axilhe, and pubic region of women. It commences like ringworm of the body, but when the deeper structures become affected, pustular indurations, resembling acne (q.v.), occur, and the hails become read ily detached. On examining the hairs under the microscope, it is seen that they am thickened; that their bulbs are partially disorganized; and that the medullary portion is atrophied.