circuit bronchoscopy battery. 6 rubber covered conducting cords for battery. 1 box bronchoscopic sponges, size 4. 1 box bronchoscopic sponges, size 5. 1 box bronchoscopic sponges, size 7. 1 box bronchoscopic sponges, size 10. 1 bite block, 1 adult. 1 bite block, child. 2 dozen extra lamps for lighted instruments. 1 extra light carrier for each instrument.* 4 yards of pipe-cleaning, worsted-covered wire.

[* Messrs. George P. Pilling and Sons who are now making these instruments supply an extra light carrier and 2 extra lamps with each instrument.]

Care of Instruments.—The endoscopist must either personally care for his instruments, or have an instrument nurse in his own employ, for if they are intrusted to the general operating room routine he will find that small parts will be lost; blades of forceps bent, broken, or rusted; tubes dinged; drainage canals choked with blood or secretions which have been coagulated by boiling, and electric attachments rendered unstable or unservicable, by boiling, etc. The tubes should be cleansed by forcing cold water through the drainage canals with the aspirating syringe, then dried by forcing pipe-cleaning worsted-covered wire through the light and drainage canals. Gauze on a sponge carrier is used to clean the main canal. Forceps stylets should be removed from their cannulae, and the cannulae cleansed with cold water, then dried and oiled with the pipe-cleaning material. The stylet should have any rough places smoothed with fine emery cloth and its blades carefully inspected; the parts are then oiled and reassembled. Nickle plating on the tubes is apt to peel and these scales have sharp, cutting edges which may injure the mucosa. All tubes, therefore, should be unplated. Rough places on the tubes should be smoothed with the finest emery cloth, or, better, on a buffing wheel. The dry cells in the battery should be renewed about every 4 months whether used or not. Lamps, light carriers, and cords, after cleansing, are wiped with 95 per cent alcohol, and the light-carriers with the lamps in place are kept in a continuous sterilization box containing formaldehyde pastilles. It is of the utmost importance that instruments be always put away in perfect order. Not only are cleaning and oiling imperative, but any needed repairs should be attended to at once. Otherwise it will be inevitable that when gotten out in an emergency they will fail. In general surgery, a spoon will serve for a retractor and good work can be done with makeshifts; but in endoscopy, especially in the small, delicate, natural passages of children, the handicap of a defective or insufficient armamentarium may make all the difference between a success and a fatal failure. A bronchoscopic clinic should at all times be in the same state of preparedness for emergency as is everywhere required of a fire-engine house.

[PLATE I—A WORKING SET OF THE AUTHOR'S ENDOSCOPIC TUBES FOR LARYNGOSCOPY, BRONCHOSCOPY, ESOPHAGOSCOPY, AND GASTROSCOPY: A, Adult's laryngoscope; B, child's laryngoscope; C, anterior commissure laryngoscope; D, esophageal speculum, child's size; E, esophageal speculum, adult's size; F, bronchoscope, infant's size, 4 mm. X 30 cm.; G, bronchoscope, child's size, 5 mm. X 30 cm.; H, aspirating bronchoscope for adults, 7 mm. X 40 cm.; I, bronchoscope, adolescent's size, 7 mm. x 40 cm., used also for the deeper bronchi of adults; J, bronchoscope, adult size, g mm. x 40 cm.; K, child's size esophagoscope, 7 mm. X 45 cm.; L, adult's size esophagoscope, full lumen construction, 9 mm. x 45 cm.; M, adult's size gastroscope. C, I, and E are also hypopharyngoscopes. C is an excellent esophageal speculum for children, and a longer model is made for adults. If the utmost economy must be practised D, E, and M may be omitted. The balance of the instruments are indispensable if adults and children are to be dealt with. The instruments are made by Charles J. Pilling & Sons, Philadelphia.]

[52] CHAPTER II—ANATOMY OF LARYNX, TRACHEA, BRONCHI AND ESOPHAGUS, ENDOSCOPICALLY CONSIDERED

The larynx is a cartilaginous box, triangular in cross-section, with the apex of the triangle directed anteriorly. It is readily felt in the neck and is a landmark for the operation of tracheotomy. We are concerned endoscopically with four of its cartilaginous structures: the epiglottis, the two arytenoid cartilages, and the cricoid cartilage. The epiglottis, the first landmark in direct laryngoscopy, is a leaf-like projection springing from the anterointernal surface of the larynx and having for its function the directing of the bolus of food into the pyriform sinuses. It does not close the larynx in the trap-door manner formerly taught; a fact easily demonstrated by the simple insertion of the direct laryngoscope and further demonstrated by the absence of dysphagia when the epiglottis is surgically removed, or is destroyed by ulceration. Closure of the larynx is accomplished by the approximation of the ventricular bands, arytenoids and aryepiglottic folds, the latter having a sphincter-like action, and by the raising and tilting of the larynx. The arytenoids form the upper posterior boundary of the larynx and our particular interest in them is directed toward their motility, for the rotation of the arytenoids at the cricoarytenoid articulations determines the movements of the cords and the production of voice. Approximation of the arytenoids is a part of the mechanism of closure of the larynx.

The cricoid cartilage was regarded by esophagoscopists as the chief obstruction encountered on the introduction of the esophagoscope. As shown by the author, it is the cricopharyngeal fold, and the inconceivably powerful pull of the cricopharyngeal muscle on the cricoid cartilage, that causes the difficulty. The cricoid is pulled so powerfully back against the cervical spine, that it is hard to believe that this muscles is inserted into the median raphe and not into the spine itself (Fig. 68).

The ventricular bands or false vocal cords vicariously phonate in the absence of the true cords, and assist in the protective function of the larynx. They form the floor of the ventricles of the larynx, which are recesses on either side, between the false and true cords, and contain numerous mucous glands the secretion from which lubricates the cords. The ventricles are not visible by mirror laryngoscopy, but are readily exposed in their depths by lifting the respective ventricular bands with the tip of the laryngoscope. The vocal cords, which appear white, flat, and ribbon-like in the mirror, when viewed directly assume a reddish color, and reveal their true shelf-like formation. In the subglottic area the tissues are vascular, and, in children especially, they are prone to swell when traumatized, a fact which should be always in mind to emphasize the importance of gentleness in bronchoscopy, and furthermore, the necessity of avoiding this region in tracheotomy because of the danger of producing chronic laryngeal stenosis by the reaction of these tissues to the presence of the tracheotomic cannula.

The trachea just below its entrance into the thorax deviates slightly to the right, to allow room for the aorta. At the level of the second costal cartilage, the third in children, it bifurcates into the right and left main bronchi. Posteriorly the bifurcation corresponds to about the fourth or fifth thoracic vertebra, the trachea being elastic, and displaced by various movements. The endoscopic appearance of the trachea is that of a tube flattened on its posterior wall. In two locations it normally often assumes a more or less oval outline; in the cervical region, due to pressure of the thyroid gland; and in the intrathoracic portion just above the bifurcation where it is crossed by the aorta. This latter flattening is rhythmically increased with each pulsation. Under pathological conditions, the tracheal outline