Pin Worm (Oxyuris Vermicularis), a nema-toid parasitic worm sometimes inhabiting the rectum of the human subject, especially in young children. This worm is white and filamentous; the male one eighth of an inch long, the female rather less than half an inch. They frequently accumulate in the rectum in considerable numbers, some being always visible in the evacuations. Under these circumstances they are apt to produce a great amount of distressing irritation in the anus and its neighborhood, especially at night after the patient has retired to rest, when they make their way out through the anus and cause a pricking, burning, and itching sensation in the delicate mucous membrane, which is sometimes almost intolerable. The disease is usually temporary, being confined as a general rule to infancy and early childhood, and disappearing spontaneously after a time. During this period, however, it may cause great discomfort, and when exaggerated in intensity may even induce serious disturbance of the health. The parasites are troublesome principally by their numbers, and the proper treatment accordingly is to evacuate them from time to time by the administration of anthelmintic remedies, or, what is better, by the habitual use of ene-mata, consisting of soap and water, or salt and water, repeated every two or three days until the symptoms are relieved.