When a cold is confined to the head it can usually be cut short by retiring to bed early, taking a ten-grain dose of Dover’s powder, followed by hot drinks to encourage the perspiration which the action of this drug produces, together with the use of as many additional bed-clothes as can be borne. Care must be taken to avoid chill on the following morning. Once it is established the condition is difficult to cure, but marked relief will often be afforded by washing out the nose with a solution made from naso-pharyngeal products. In fact, a simple nasal glass douche should form part of the traveller’s outfit, at least, if he is liable to bad colds in the head. In tropical regions five grains of quinine should be added to the dose of Dover’s powder. When there is a liability to colds in the head the use of preventive vaccines is recommended, but these should not be employed without the advice of a medical man. _Cystitis, or Inflammation of the Bladder._ _Causes._—Injury or the result of operations, extension of inflammations such as gonorrhœa, retention and decomposition of urine; debilitated or gouty persons are especially liable to this affection. _Symptoms._—Intense pain in the lower part of the belly, and in the crutch, continual desire to pass water, with frequent passage of small quantities. The urine is scanty, high-coloured, foul-smelling, and occasionally blood-stained, and there may be some fever. _Treatment._—Hot baths, leeches, or fomentations to the crutch, and a sedative, such as opium (preferably given by the bowel), will be required. If the disease continues the bladder should be washed out through a catheter with weak boric acid solution, five grains to the ounce, or chinosol (1 in 2000), twice a day. Urotropin, ten grains, and copaiba or sandal-wood oil in ten-drop doses. The diet should be restricted to milk. _Dengue._ This disease, also known as dandy fever and break-bone fever, occurs in many parts of the world, and it is most common along littorals, probably because the Stegomyia mosquito which carries the infection is usually numerous in sea-coast places. _Cause._—The organism of dengue fever is unknown, but the infection has been proved to be carried by at least one species of mosquito.