=Treatment.=--As the presence of tick is far from agreeable, the insect may often be removed by painting it with turpentine, which either kills it or causes the claws to be relaxed; in either case the tick loosens its hold and drops to the ground. A tropical variety, carapato, buries the whole head in the flesh of its host before it is perceived, and if turpentine does not loosen its hold, the head must be dug out with a clean needle or knife blade. =LICE= (_Pediculi_).--Head lice are most common. They are gray with black margins, about one-twenty-fifth to one-twelfth inch long, and wingless. The color changes with the host, as the lice are black on the negro, and white in the case of the Eskimos. The female lays fifty to sixty eggs ("nits"), seen as minute, white specks glued to the side of a hair; usually not more than one or two on a single hair. The eggs hatch in six days. The irritation produced by the presence of the parasites on the head leads to general itching, more particularly on the lower part of the back of the head. The constant scratching starts an inflammation of the skin with the formation of pimples, weeping spots, and crusts, from the dried discharge, possessing a bad odor. The denuded spots becoming infected, the neighboring glands enlarge and are felt as tender lumps beneath the skin at the back of the neck, under the jaw, or at either side of the neck. Whenever there are persistent itching and irritation of the scalp, particularly at the back of the head, lice or "nits" should be sought for. Sometimes it is more easy to find them on a fine-tooth comb passed through the hair. Lice are very common in dirty households, and are occasionally seen on the most fastidious persons, who accidentally acquire them in public places or conveyances. =Treatment.=--The hair should be cut short when permissible. Any crusts on the head should be softened by the application of sweet oil, and then removed by washing in soap and warm water. Petroleum or kerosene is a good remedy. It must be rubbed on the head two successive nights, the head being covered by a cap, and washed off each morning with hot water and soap. The patient must be cautioned not to approach an open flame after kerosene has been put on his head. The eggs or "nits" are next to be attacked with vinegar, which is sponged on the hair and the fine-tooth comb plied daily for a week. The remaining irritation of the scalp can be cured by washing the head daily and applying sweet oil. A simpler plan consists of drenching hair and scalp twice with cold infusion of (poisonous) larkspur seed, made by steeping for an hour an ounce of the seed in six ounces of hot water. This treatment will destroy both insects and eggs. After twenty-four hours the hair and scalp must be shampooed with warm water thoroughly.