_Treatment._—When the worm can be seen at the base of the little ulcer, it may be secured to a piece of match and a small portion may be wound on to the match daily. If attempts are made to forcibly draw it out, it will probably break and violent inflammation will result. During the time that the worm is being wound out, the part should be kept very clean and an antiseptic ointment applied. There are other methods of treatment, but these can only be carried out under medical supervision. _The Hook Worm._—This is the American name for one or other of the species of ankylostomes which infect man. The disease they cause is known as ankylostomiasis, and it is common in many parts of the world, especially in the tropics. It chiefly affects natives, owing to their habits; but it occurs also in Europeans. _Cause._—Hook worms are small, almost cylindrical worms, which inhabit the human small intestine, to the wall of which they attach themselves by means of their mouths, which are furnished with formidable hooks and lancets. They suck blood, and the symptoms they produce are due in part to loss of blood, in part to the destruction of the lining membrane of the bowel, and possibly also in part to the effects of a poison which they are believed to excrete. Their eggs are passed in the excrement, and develop in the infected soil into larvæ, which are able to penetrate the unbroken skin if they come in contact with it. This is the most important route of infection, but it may occur also by means of infected drinking water and from contaminated food. _Symptoms._—The most marked feature of the disease is anæmia, which is often associated with digestive troubles. Palpitation of the heart and shortness of breath are frequently met with. In bad cases the appetite is disordered or depraved. The patient becomes pot-bellied, and there is swelling, chiefly about the face and ankles. The face is frequently puffy, and the skin assumes a peculiar earthy hue. It should be noted that a very early symptom is what is called ground itch. This is a skin eruption, usually on the feet and legs, due to the irritation caused by the larvæ penetrating the epidermis. _Prophylaxis._—The chief measure consists in preventing contamination of the soil by infected excrement. It is therefore important when camping to make proper provision in the way of latrines. Care must also be taken to prevent the fouling of water and food stuffs, such as vegetables, which are eaten uncooked. It is very dangerous to go about bare-foot in regions where the disease occurs, and camping sites should always be thoroughly cleansed.