_Tape Worms._—These worms may measure many feet in length; and their presence in the body can only be certainly known by the appearance of some of the segments or portions of the worm in the motions although hunger and dyspepsia may be complained of. _Treatment._—Administer a good aperient overnight so as to empty the bowels; after the aperient nothing should be given by the mouth for eight hours, then give sixty to one hundred and twenty drops of the liquid extract of male fern in one ounce of thin gruel, milk, or gum water, and follow this up in four hours by a good meal, and an aperient to remove the worm, which should now be dead. When the extract of male fern is not available, one tablespoonful of the oil of turpentine may be used in its place. If later on fresh segments appear in the motions, then the treatment must be repeated. _Round Worm._—The round worm resembles the garden worm and is several inches in length; it may be observed in the vomit but more commonly is seen in the motions. The symptoms are similar to those caused by the tape worm and the treatment is the same, except that, instead of the male fern, two to five grains of santonin should be given in a little milk; and the treatment repeated every other day for a week. _Threadworm._—The threadworm is a small round worm usually measuring less than half an inch in length; it inhabits the lower end of the bowel and causes great heat and itching about the outlet, especially at night. _Treatment._—Wash out the lower bowel and inject into it about a third of a pint of tea, or a similar quantity of water containing one teaspoonful of salt, tannin, or alum; then apply a little mercurial ointment around the outlet to diminish irritation. This should be done every third day till the worms have disappeared from the motions. _The Guinea Worm._—The guinea worm often measures several feet in length; it chiefly causes trouble in the feet, ankles, and legs, where in order to obtain an exit from the body it penetrates the skin, causing a small ulcer at its point of exit. Usually the presence of the guinea worm is attended with inflammation and the formation of matter. _Prophylaxis._—Infected persons should be kept away from water supplies, and such sources of water supply as wells and water holes should be protected. In areas where guinea worm occurs, all water should be boiled. If this cannot be managed, it should be filtered through a piece of clean cotton cloth, as this will remove from it the small crustacean in which the larva of the guinea worm develops. Another method of treating infected water is by means of permanganate of potash, one ounce to every 2,000 gallons of well water. Caustic potash and quicklime are also effective.