The cannula is passed along the nares till the end reaches the pharynx, then the stylet is protruded and arches forward till it reaches the teeth, when a thread is passed through the hole, and the stylet being withdrawn, the thread is carried with it into the pharynx and through the nostril, where it can be used to draw the plug into its place at the posterior nares. =Tooth Drawing.=—A surgeon is frequently required to draw a tooth on emergency, and should be provided with instruments (see fig. 75). Seven pairs of forceps and an elevator are sufficient for all he is likely to deal with. They are differently shaped for the different teeth, which vary much at the neck, the part grasped in the forceps. [Illustration: Fig. 75.—Tooth Forceps.] For the operation the patient should be seated in a high-backed chair; the surgeon stands at his right side, holds the jaw with his left hand, while with the right he thrusts the beaks of the forceps between the gum and the tooth on its lingual and buccal aspects; having reached the neck, he holds the tooth firmly, pushing it inwards and outwards with a rotary motion of the wrist (except for the molar teeth). Sudden tugs break the tooth and leave the fang behind; when loosened by rotation and lateral motion, the forceps readily lift the tooth out of its socket. For the _upper incisors_ the beaks of the forceps are straight, slightly hollowed inside, to give them hold of the teeth, and have crescentic edges (see fig. 76). The _upper incisors_ and _canines_ can be drawn by the same pair, as the shape of these teeth at the neck varies to a small extent. For the _lower incisors_ a very narrow forceps is necessary. The beaks (fig. 77) should be curved at the joint sufficiently to form an angle of 25° with the handles, that the latter may clear the upper jaw. The edge of the beaks is crescentic, similar to that of the upper incisors. These forceps are also very useful for removing roots, as their fineness enables them to sink between the stump and the alveolus with ease. [Illustration: Fig. 76.—Upper incisor tooth and forceps.] [Illustration: Fig. 77.—Lower central incisor and forceps.] [Illustration: Fig. 78.—External aspect of upper bicuspid tooth, and bicuspid forceps.] For the _bicuspids_, beaks with crescentic edges also are used, but the inside of the beak is more hollowed to fit the round neck of these teeth (see fig. 78). All the bicuspids can be drawn with the same pair, but it is convenient to have forceps bent at the joint to clear the upper jaw when extracting a lower bicuspid (see fig. 79). [Illustration: Fig. 79.—Lower bicuspid forceps.] For the _upper molars_ two forceps are required, one for each side of the jaw; the beaks of these are well hollowed to admit the crown of the tooth. The inner beak terminates in a crescentic border to fit the large internal fang (see figs. 80 & 81); the outer beak has two smaller grooves separated by a point, that passes between the two external fangs.