The oesophagus lined with gastric mucous membrane.

Peptic oesophagitis and peptic ulceration of the squamous epithelium of the oesophagus are secondary to regurgitation of digestive juices, are most commonly found in those patients where the competence ofthe cardia has been lost through herniation of the stomach into the mediastinum, and have been aptly named by Barrett (1950) " reflux oesophagitis." In the past there has been some discussion about gastric heterotopia as a cause of peptic ulcer of the oesophagus, but this point was very largely settled when the term reflux oesophagitis was coined. It describes accurately in two words the pathology and aetiology of a condition which is a common cause of digestive disorder. In the same paper Barrett for the first time drew a sharp distinction between the above and lesions which had previously been described by pathologists as peptic ulcers of the oesophagus, but which in fact were gastric ulcers occurring in gastric mucous membrane lining a viscus which, from the outside, looked like oesophagus. In retrospect it is now easy to see how the confusion had arisen. Peptic ulcer of the oesophagus is associated with dense submucous fibrosis. The ulcer itself tends to remain superficial; it may ooze blood, but rarely causes severe and sudden bleeding and does not perforate. It causes fibrous stenosis. Patients with this condition may die at home, but if they come to necropsy the stricture may be missed, the hernia is almost certainly missed, and the lesion, if found, is described as a simple stricture. There is little that seems worthy ofpreservation in a museum, especially when the lesion is made even more insignificant by severe post-mortem digestion. When a part of the oesophagus is lined with gastric mucous membrane, and a gastric ulcer occurs within this area, it behaves, as Barrett has shown, like an ulcer in the abdominal stomach; it may cause stenosis, it may bleed profusely, and it may perforate. A lesion such as this that perforates into the pleura immediately attracts the attention of the pathologist, and is