Such deformities as absence of the nose and its cavities, and stenosis, are usually parts of a general malformation, chiefly Cyclopia (see p. 49). In Clefts of the lip and palate, the nasal cavities are in communication to a greater or less extent with the mouth. This communication renders the mucous membrane of the nares liable to inflammation. Normally, the nasal passages are protected against any irritation except that of the air passing through them, and the mucous membrane is correspondingly sensitive. We know how the accidental passage of a piece of solid food into the nares causes great irritation, and we shall afterwards see that the existence of a foreign body in the nares is a frequent cause of prolonged catarrh. In cases of cleft palate the food and secretions of the mouth readily pass into the nares, and, although a certain tolerance may be established, persons so affected are peculiarly liable to catarrh of the nares.