_Prickly Heat._—This condition is very frequent, especially in the moist tropics. It is due to free sweating, and is accompanied by intense heat and itching. The parts closely covered by clothing are specially apt to be affected. The skin becomes covered with numerous slightly inflamed papules, set close together, and the eruption may remain for months at a time, varying in intensity according to circumstances. _Prophylaxis._—Avoid long drinks, warm clothing, too much exercise, and all conditions producing excessive perspiration. Sea-bathing should be avoided, and soap should not be used in the bath. One should sleep under as hygienic conditions as possible, with a well-ventilated bed and without unnecessary clothing. A dusting powder of equal parts of boric acid, oxide of zinc, and starch is useful. _Treatment._—Ryan strongly recommends the so-called “Sulphaqua” bath charge, which is sold in packets ready for use. The above-mentioned dusting powder is helpful, as is the application of a lotion containing salicylic acid and spirit. Some prefer oily applications. Whatever is used, care should be taken to see that the bowels are well opened at the beginning of an attack, preferably by a saline purge. _Ulcers._—Ulcers are often very troublesome to the traveller, as the healing process is frequently retarded by exposure, dirt and dust, and the chafing of clothes. Want of sufficient animal food greatly favours the spread of large ulcers. A simple dressing of iodoform ointment, or ointment of boric acid, is effective when the ulcer can be protected, and rest can be given to the affected part. When the ulcer is deep and large it may be stimulated to heal by the application of lint or cotton-wool, moistened with carbolic oil, carbolic lotion, or other antiseptics. Large, unhealthy ulcers should be well bathed with some antiseptic such as carbolic acid, one in sixty of water, or a solution of chinosol (1 in 600); and after the sore has been cleansed it may be lightly dusted with iodoform and then covered with a piece of lint moistened with carbolic oil or smeared with iodoform ointment and supported by an evenly applied bandage. Boric ointment, lano-creoline, izal ointment or other antiseptic dressing may take the place of iodoform ointment. In addition to the above general account, certain conditions leading to ulceration require consideration. _Oriental Sore._—This condition is commonly known as Baghdad Boil, Aleppo Button, Frontier Sore, etc. It occurs in various hot countries, such as Egypt, Syria, Asia Minor, Arabia, and Mesopotamia, and has been met with in Europe and Greece. A special form affecting both skin and mucous membranes is widely distributed in South America.