(_b_) =Wounding the tongue.=--This is most likely to occur under nitrous oxide, as the tongue during anæsthesia is generally swollen, and is, moreover, not under the control of the patient. Wounding the tongue is nearly always due to carelessness, and arises generally in using the elevator. When the tongue is _much lacerated_, the overhanging portions should be trimmed off with scissors and the surface kept clean with antiseptic mouth washes. If the _tongue is punctured and the wound does not involve a large branch of the lingual artery_, but yet bleeds freely, the tongue should be drawn forward; if this does not prove successful the insertion of a stitch will generally cause the hæmorrhage to cease. _If the tongue is punctured and a large branch of the lingual artery is involved_, the finger should be placed on the back of the tongue and the organ drawn forward; this compresses the lingual artery against the hyoid bone. The bleeding point must then be sought for and, if found, an attempt made to twist the wounded vessel. If this fails cauterisation may be tried, and as a last resource, if cauterisation does not stop the bleeding, the lingual artery must be tied. (_c_) =Bruising the lower lips.=--This may occur in the removal of upper bicuspids and molars, and is due to having the mouth insufficiently opened, and using forceps of too straight a pattern. (_d_) =Injury of the mandibular nerve.=--The mandibular nerve may be injured during the removal of the lower molars and bicuspids. Loss of sensation over the parts supplied by the nerve, with dribbling of saliva, generally follows the accident. Sensation is, however, usually restored, and in cases of laceration the nerve generally unites. Mr. Sewill records a case in which “the roots of a lower wisdom tooth contained a groove and a foramen, through which the inferior dental nerve had evidently passed.” (_e_) =Hæmorrhage following tooth extraction= is a most important complication, and one which needs prompt treatment. Hæmorrhage is predisposed to by a diathesis known as hæmophylia. Of its pathology but little seems to be definitely known. The blood in this condition is said by Walsham to be deficient in fibrin. Hæmorrhage may occur in people not predisposed to the above-named diathesis; in some instances it is probably due to pathological changes in the artery supplying the tooth, these changes being frequently induced by inflammation around the apex of the root, and the vessel becoming adherent to its bony surrounding, and thus prevented from contracting. Another condition, which may or may not have any practical bearing, is the occurrence of hæmorrhage during the menstrual period. I have, on two occasions, had under notice patients for whom teeth have been extracted during this period, and in whom hæmorrhage followed, but ceased at the termination of the period. Teeth had been extracted for both these patients on previous occasions, without undue hæmorrhage following.