To facilitate catherization the pharynx and epiglottic region may be cocainized with a 5 per cent. solution before induction. Hill’s endoscope (Fig. 34) is distally illuminated by a small electric lamp, which is connected with a small pocket battery. A useful modification of this has been devised by Mr Dott. In it, the catheter is passed along a separate compartment, so that the view of the glottis is undisturbed. The point of the catheter comes into view at the distal extremity of the endoscope and can be guided between the cords into the trachea. [Illustration: FIG. 34.--Hill’s Direct Laryngoscope.] It is essential before attempting intubation, that there should be thorough relaxation. The lower jaw should be so slack that a gag is not required. The head is then placed in the occipito-shoulder position, or is allowed to hang over the end of the table. The tongue is controlled by forceps, and the endoscope passed slowly along its dorsum until the epiglottis comes into view. The point of the endoscope is then passed sufficiently far below the tip of the epiglottis to ensure that it will not slip; too deep insertion must be avoided. The endoscope being held in the left hand, the hyoid bone is lifted up by a tilting movement of the hand. The glottis is thus brought into view. The catheter stiffened by means of a probe is then passed through the glottis into the trachea and the endoscope withdrawn. The bifurcation of the trachea in the adult is at a distance of about 26 cm. from the incisor teeth. The catheter should be marked accordingly, and inserted to a point just short of this. The probe is then withdrawn, and connection made with the air current. It occasionally happens that unexpected difficulty is met with on attempting to pass the catheter by direct vision. The larynx may be so fixed that the glottis does not readily come into view; or in the case of an intraoral neoplasm the view may be obstructed by the presence of blood. In such cases the catheter can be introduced by the indirect method. The middle finger of the left hand is passed along the dorsum of the tongue until the epiglottis is felt. The index finger is then used to guide the point of the catheter to the glottis through which it is then passed. No undue force must be used. A stilette should be inserted into the catheter which should be moulded almost to a right angle at its terminal third. If the stilette is withdrawn when the point of the catheter is over the mouth of the glottis, the instrument will, as a rule, slip easily into the trachea. Occasionally the tube passes into the œsophagus. With care and adequate relaxation such a mistake should not occur, but the possibility of it should be kept in mind. If the operator will abstain from attempting to pass the catheter until such time as he has a satisfactory view of the glottis, mistakes of this kind will seldom occur. The essentials are a good illumination and an adequate relaxation.