bronchoscope is in situ. Furthermore, the instruments must be of the proper model and well made; otherwise difficulties and dangers will attend attempts to see them.

Laryngoscopes.—The regular type of laryngoscope shown in Fig. I (A, B, C) is made in adult's, child's, and infant's sizes. The instruments have a removable slide on the top of the tubular portion of the speculum to allow the removal of the laryngoscope after the insertion of the bronchoscope through it. The infant size is made in two forms, one with, the other without a removable slide; with either form the larynx of an infant can be exposed in but a few seconds and a definite diagnosis made, without anesthesia, general or local; a thing possible by no other method. For operative work on the larynx of adults, such as the removal of benign growths, particularly when these are situated in the anterior portion of the larynx, a special tubular laryngoscope having a heart-shaped lumen and a beveled tip is used. With this instrument the anterior commissure is readily exposed, and because of this it is named the anterior commissure laryngoscope (Fig. 1, D). The tip of the anterior commissure laryngoscope can be used to expose either ventricle of the larynx by lifting the ventricular band, or it may be passed through the adult glottis for work in the subglottic region. This instrument may also be used as an esophageal speculum and as a pleuroscope. A side-slide laryngoscope, used with or without the slide, is occasionally useful.

Bronchoscopes.—The regular bronchoscope is a hollow brass tube slanted at its distal end, and having a handle at its proximal or ocular extremity. An auxiliary canal on its under surface contains the light carrier, the electric bulb of which is situated in a recess in the beveled distal end of the tube. Numerous perforations in the distal part of the tube allow air to enter from other bronchi when the tube-mouth is inserted into one whose aerating function may be impaired. The accessory tube on the upper surface of the bronchoscope ends within the lumen of the bronchoscope, and is used for the insufflation of oxygen or anesthetics, (Fig. 2, A, B, C, D).

For certain work such as drainage of pulmonary abscesses, the lavage treatment of bronchiectasis and for foreign-body or other cases with abundant secretions, a drainage-bronchoscope is useful The drainage canal may be on top, or on the under surface next to the light-carrier canal. For ordinary work, however, secretion in the bronchus is best removed by sponge-pumping (Q.V.) which at the same time cleans the lamp. The drainage bronchoscope may be used in any case in which the very slightly-greater area of cross section is no disadvantage; but in children the added bulk is usually objectionable, and in cases of recent foreign-body, secretions are not troublesome.

As before mentioned, the lower air passages will not tolerate dilatation; therefore, it is necessary never to use tubes larger than the size of the passages to be examined. Four sizes are sufficient for any possible case, from a newborn infant to the largest adult. For infants under one year, the proper tube is the 4 mm. by 30 cm.; the child's size, 5 mm. by 30 cm., is used for children aged from one to five years. For children six years or over, the 7 mm. by 40 cm. bronchoscope (the adolescent size) can be used unless the smaller bronchi are to be explored. The adult bronchoscope measures 9 mm. by 40 cm.

The author occasionally uses special sizes, 5 mm. x 45 cm., 6 mm. x 35 cm., 8 mm. x 40 cm.

Esophagoscopes.-The esophagoscope, like the bronchoscope, is a hollow brass tube with beveled distal end containing a small electric light. It differs from the bronchoscope in that it has no perforations, and has a drainage canal on its upper surface, or next to the light-carrier canal which opens within the distal end of the tube. The exact size, position, and shape of the drainage outlets is important on bronchoscopes, and to an even greater degree on esophagoscopes. If the proximal edge of the drainage outlet is too near the distal end of the endoscopic tube, the mucosa will be drawn into the outlet, not only obstructing it, but, most important, traumatizing the mucosa. If, for instance, the esophagoscope were to be pushed upon with a fold thus anchored in the distal end, the esophageal wall could easily be torn. To admit the largest sizes of esophagoscopic bougies (Fig. 40), special esophagoscopes (Fig. 5) are made with both light canal and drainage canal outside the lumen of the tube, leaving the full area of luminal cross-section unencroached upon. They can, of course, be used for all purposes, but the slightly greater circumference is at times a disadvantage. The esophageal and stomach secretions are much thinner than bronchial secretions, and, if free from food, are readily aspirated through a comparatively small canal. If the canal becomes obstructed during esophagoscopy, the positive pressure tube of the aspirator is used to blow out the obstruction. Two sizes of esophagoscopes are all that are required—7 mm. X 45 cm. for children, and 10 mm. X 53 cm. for adults (Fig. 3, A and B); but various other sizes and lengths are used by the author for special purposes.* Large esophagoscopes cause dangerous dyspnea in children. If, it is desired to balloon the esophagus with air, the window plug shown in Fig. 6, is inserted into the proximal end of the esophagoscope, and air insufflated by means of the hand aspirator or with a hand bulb. The window can be replaced by a rubber diaphragm with a perforation for forceps if desired. It will be noted that none of the endoscopic tubes are fitted with mandrins. They are to be introduced under the direct guidance of the eye only. Mandrins are obtainable, but their use is objectionable for a number of reasons, chief of which is the danger of overriding a foreign body or a lesion, or of perforating a lesion, or even the normal esophageal wall. The slanted end on the esophagoscope obviates the necessity of a mandrin for introduction. The longer the slant, with consequent acuting of the angle, the more the introduction is facilitated; but too acute an angle increases the risk of perforating the esophageal wall, and necessitates the utmost caution. In some foreign-body cases an acute angle giving a long slant is useful, in others a short slant is better, and in a few cases the squarely cut-off distal end is best. To have all of these different slants on hand would require too many tubes. Therefore the author has settled upon a moderate angle for the end of both esophagoscopes and bronchoscopes that is easy to insert, and serves all purposes in the version and other manipulations required by the various mechanical problems of foreign-body extraction. He has, however, retained all the experimental models, for occasional use in such cases as he falls heir to because of a problem of extraordinary difficulty.

* A 9 mm. X 45 cm. esophagoscope will reach the stomach of almost all adults and is somewhat easier to introduce than the 10 mm. X 53 cm., which may be omitted from the set if economy must be practiced.

[FIG. I.—Author's laryngoscopes. These are the standard sizes and fulfill all requirements. Many other forms have been devised by the author, but have been omitted from the list as unnecessary. The infant diagnostic laryngoscope (C) is not for introducing bronchoscopes, and is not absolutely necessary, as the larynx of any infant can be inspected with the child's size laryngoscope (B).

A Adult's size; B, child's size; C, infant's diagnostic size; D, anterior commissure laryngoscope; E, with drainage canal; 17, intubating laryngoscope, large lumen. All the laryngoscopes are preferred without drainage canals.]

[FIG. 2.—The author's bronchoscopes of the sizes regularly used. Various other lengths and diameters are on hand for occasional use for special purposes. With the exception