[17] CHAPTER I—INSTRUMENTARIUM Direct laryngoscopy, bronchoscopy, esophagoscopy and gastroscopy are procedures in which the lower air and food passages are inspected and treated by the aid of electrically lighted tubes which serve as specula to manipulate obstructing tissues out of the way and to bring others into the line of direct vision. Illumination is supplied by a small tungsten-filamented,... more...