But the Hole ought to be well stopt with Bolsters, because the _Dura Mater_ is sometimes so much inflam'd, that it bursts forth; so that if any Excrescences arise therein, and go out of the Hole, having small Roots, they may be bound and cut; but if their Roots be large, they must be press'd close with little Bolsters steept in Spirituous Medicines. Here it may not be improper to observe, that the Operation of the Trepan ought to be perform'd more gently in Children than in adult Persons, in regard that their Bones are more tender, and that Oily Medicines must not be us'd, but Spirituous. The Exfoliation is made sometimes sooner, and sometimes later; but the _Callus_ usually covers the opening of the Skull within the space of forty or fifty Days, if no ill Accident happens. In great Fractures, where there is no longer any connexion between the Bones, it is requisite to take 'em away. _Of the Bandage of the Trepan._ The proper Bandage to be us'd after the Operation of the Trepan, is the great Kerchief, which is a large Napkin folded into two parts after such a manner that the side which toucheth the Head exceeds that which doth not touch it in the breadth of four Fingers; it is apply'd to the Head in the middle, whilst a Servant holds the Dressing with his Hand: Then the two upper ends of the Napkin being brought under Chin, the Surgeon takes the two lower, and draws 'em streight by the sides, so as that side the Napkin, which is four Fingers broader {214} than the other, may be laid upon the Forehead: Afterward the two ends of the Napkin are cross'd behind the Head, and fasten'd at their Extremities with Pins, without making any Folds, that might hurt the Part; but the ends of the Napkin which fall upon the Shoulders, are rais'd up to the Head near the lesser Corner of the Eyes; and the two ends under the Chin are fasten'd with Pins, or else tied in a Knot. * * * * * CHAP. II. _Of the Operation of the _Fistula Lachrymalis_._ This Operation is perform'd when there is a Fistulous Ulcer in the great Corner of the Eye, after this manner: The Patient being plac'd in a convenient Posture, and having his sound Eye bound up, to take away the sight of the Instruments; the Operator causeth the other Eye to be kept steady with a Bolster held with an Instrument, and makes an Incision with a Lancet in form of a Crescent upon the Tumour, taking care to avoid cutting the Eye-Lid and the little Cartilage which serves as a Pulley to the great Oblique Muscle. If the Bone be putrify'd with a _Caries_, an Actual Cautery may be apply'd thereto, using for that purpose a small Funnel or Tube, thro' the Canal of which the Cautery is convey'd to the Bone. {215} But the Bone must not be pierc'd, for it is exfoliated entire by reason of its smallness; and so the Hole is made without any Perforation. _The Dressing and Bandage of the _Fistula Lachrymalis_._