_Lens-system ballooning gastroscopy_ may possibly afford additional information after all possible data from open-tube gastroscopy has been obtained. Care must be exercised not to exert an injurious degree of air-pressure. The distended portion of the stomach assumes a funnel-like form ending at the apex in a depression with radiating folds, that leads the observer to think he is looking at the pylorus. The foreshortening produced by the lens system also contributes to this illusion. The best lens-system gastroscope is that of Henry Janeway, which combines the open-tube and the lens system. _Gastroscopy for Foreign Bodies_.--The great majority of foreign bodies that reach the stomach unassisted are passed per rectum, provided the natural protective means are not impaired by the administration of cathartics, changes in diet, etcetera. This, however, does not mean that esophageal foreign bodies should be pushed into the stomach by blind methods, or by esophagoscopy, because a swallowed object lodged in the esophagus can always be returned through the mouth. Foreign bodies in the stomach and intestines should be fluoroscopically watched each second day. If an object is seen to lodge five days in one location in the intestines, it should be removed by laparotomy, since it will almost certainly perforate. Certain objects reaching the stomach may be judged too large to pass the pylorus and intestinal angles. These should be removed by gastroscopy when such decision is made. It is to be remembered that gastric foreign bodies may be regurgitated and may lodge in the esophagus, whence they are easily removed by esophagoscopy. The double-planed fluoroscope of Manges is helpful in the removal of gastric foreign bodies, but there is great danger of injury to the stomach walls, and even the peritoneum, unless forceps are used with the utmost caution. [277] CHAPTER XXXVI--ACUTE STENOSIS OF THE LARYNX _Etiology_.--Causes of a relatively sudden narrowing of the lumen of the larynx and subjacent trachea are included in the following list. Two or more may be combined. 1. Foreign body. 2. Accumulation of secretions or exudate in the lumen. 3. Distension of the tissues by air, inflammatory products, serum, pus, etc. 4. Displacement of relatively normal tissues, as in abductor paralysis, congenital laryngeal stridor, etcetera. 5. Neoplasms. 6. Granulomata.