This may supervene upon acute catarrh, or it may be of more independent origin. The presence of foreign • bodies not infrequently leads to an inveterate discharge from the nares, more especially in children. The prolonged existence of catarrh leads to various changes in the mucous membrane. There may be Atrophy with induration, a process similar to cirrhosis. In this case there is frequently an excessive purulent discharge (Ozasna), which usually has a very foetid smell. In other cases' there is Hypertrophy of the mucous membrane, which may even amount to a distinct polypus (see below). The finer ramifications of the olfactory nerves are injured by these tissue changes and smell is lost or impaired, in many cases permanently.