[FIG. 3.--The author's esophagoscopes of the sizes he has standardized for all ordinary requirements. He uses various other lengths and sizes for special purposes, but none of them are really necessary. A gastroscope, 10 mm. X 70 cm., is useful for adults, especially in cases of gastroptosis. Drainage canals are placed at the top or at the side of the tube, next to the light-carrier canal. A, Adult's size, 10 mm. X 53 cm.; B, child's size, 7 mm. X 45 cm.; C and D, full lumen, with both light canal and drainage canal outside the wall of the tube, to be used for passing very large bougies. This instrument is made in adult, child, and adolescent (8 mm. by 45 cm.) sizes. Gastroscopes and esophagoscopes of the sizes given above (A) and (B), can be used also as gastroscopes. A small form of C, 5 mm. X 30 cm. is used in infants, and also as a retrograde esophagoscope in patients of any age. E, window plug for ballooning gastroscope, F.] [FIG. 4.--Author's short esophagoscopes and esophageal specula A, Esophageal speculum and hypopharyngoscope, adult's size; B, esophageal speculum and hypopharyngoscope, child's size; C, heavy handled short esophagoscope; D, heavy handled short esophagoscope with drainage.] [FIG. 5.--Cross section of full-lumen esophagoscope for the use of largest bourgies. The canals for the light carrier and for drainage are so constructed that they do not encroach upon the lumen of the tube.] [25] The special sized esophagoscopes most often useful are the 8 mm. X 30 cm., the 8 mm. X 45 cm., and the 5 mm. X 45 cm. These are made with the drainage canal in various positions. For operations on the upper end of the esophagus, and particularly for foreign body work, the esophageal speculum shown at A and B, in Fig. 4, is of the greatest service. With it, the anterior wall of the post-cricoidal pharynx is lifted forward, and the upper esophageal orifice exposed. It can then be inserted deeper, and the upper third of the esophagus can be explored. Two sizes are made, the adult's and the child's size. These instruments serve, very efficiently as pleuroscopes. They are made with and without drainage canals, the latter being the more useful form. [FIG. 6.--Window-plug with glass cap interchangeable with a cap having a rubber diaphragm with a perforation so that forceps may be used without allowing air to escape. Valves on the canals (E, F, Fig. 3) are preferable.] _Gastroscopes_.--The gastroscope is of the same construction as the esophagoscope, with the exception that it is made longer, in order to reach all parts of the stomach. In ordinary cases, the regular esophagoscopes for adults and children respectively will afford a good view of the stomach, but there are cases which require longer tubes, and for these a gastroscope 10 mm. X 70 cm. is made, and also one 10 mm. X 80 cm., though the latter has never been needed but once.