_Night blindness and snow blindness_ are due to exposure to the glare either of the sun or of the snow. To avoid these complaints tinted glasses should be worn. Travellers in snowy regions should be provided with smoked glasses; if these get broken or lost, some opaque substance may be smeared over the surface of an ordinary pair, leaving a narrow horizontal slit of clear glass—in the Esquimaux fashion, as shown in the accompanying illustration. On snow it must be remembered that the perforated wire gauze sides are essential for protection from the reflected rays of the sun. Elastic may be substituted with advantage for the ordinary metallic attachments, between the glasses as well as around the head. _Jaundice._ Jaundice, which is a condition in which the skin and mucous membranes assume a yellow colour, may be due to various causes. One of the commonest forms is that known as catarrhal jaundice, which is induced by chill, exposure, dietetic disturbances, etc. It should be treated by calomel and salines. Violent purges are to be avoided. Bismuth and bicarbonate of soda should be given, and the diet should be regulated and should consist of simple and bland articles of food, free, as far as possible, from fats. There is a form of jaundice associated with infective conditions, such as the enteric fevers, dysentery, malaria, relapsing fever and yellow fever. In these cases the jaundice is to be treated like the catarrhal form, and the accompanying condition requires attention. In addition to the above there is a camp or infectious jaundice, the nature of which is somewhat obscure, but which is associated with a considerable degree of illness. _Symptoms._—The condition commonly begins with shivering, a rise of temperature, headache, giddiness, general malaise, sleeplessness, loss of appetite, nausea, and it may be vomiting. The tongue is coated, and there may be pains in the back and legs. The jaundice usually lasts from seven to nine days, and about the fifth day the temperature falls, though there may be a secondary fever. _Prophylaxis._—So far as we know at present this is a question of enforcing good sanitary surroundings, and paying special attention to the hygiene of food and drinks, which should be guarded from the access of flies. _Treatment._—This is entirely symptomatic and should be that of any ordinary febrile attack, together with the measures employed in catarrhal jaundice. There is a severe form of jaundice of an infective nature which is associated with the presence of a parasite in the blood, very like that of yellow fever, and which apparently is derived from infected rats. This form of jaundice is, however, not very common and need not be further considered, especially as it requires skilled medical attendance. _Laryngitis, or Inflammation of the Upper Part of the Windpipe._ The organ of the voice is called the “larynx.”