The Incisions are to be made with the Incision-Knife, and that too boldly when there are no Sinkings; but if there be any, too much weight must not be laid upon 'em: Thus the Incision being finish'd, the Lips of the Skull are to be separated either with the Fingers, or some convenient Instrument; Then if there be no urgent Occasion to apply the Trepan, it may be deferr'd till the next Day, the Wound being dress'd in the mean time with Plaisters, Bolsters, Pledgets, and a large Kerchief or upper Dressing, the use of which we shall shew hereafter.
The Operation is begun with the Perforative, to make a little Hole for the fixing of the Pyramid or Pin which is in the Round; afterward the Round is to be apply'd, holding the Handle of the Trepan with the Left-hand, and turning with the other very fast in the beginning; but when the Round hath made its way, it is lifted up to remove the Pin, lest this Point shou'd hurt the Dura Mater: Thus the Round being taken off from time to time, to be cleans'd from the Filings that stick thereto, is set on again, and the Operator begins his Work of turning anew, which must be carry'd on gently when any Blood appears, to the end that the first Table of the piece of Bone which is remov'd may not fly from the second: When it comes near the Dura Mater, the Operator must proceed, in like manner, gently, searching with a Feather round about the Bone, to observe whether he still continueth his Course in the Skull. He must also often lift up the Trepan to search the Hole, to cleanse the Instrument, and to keep
it from growing hot. As often as the Trepan is taken off, let him search with a Feather, to see whether the Bone be cut equally; and if it be not, he must lean more on that side which is least cut. If it be necessary to make use of the Terebella, the Hole must be made in the beginning, whilst the Bone is as yet firm; and when the Piece begins to move, the Terebella is to be put very gently into its Hole, without pressing the Bone, to draw it out; or else it may be taken away with the Myrtle-Leaf, which is an Instrument made of a firm Silver-Plate somewhat crooked. When the Piece is thus remov'd, the uneven Parts that remain at the bottom of the Hole, are to be cut with the Lenticula; and if there be any Sinkings, they may be rais'd with the Elevatory. Whereupon the Dura Mater may be compress'd a little with the Lenticula, to facilitate the running out of the Blood, the Wounded Person being oblig'd to stoop with his Head downward, stopping his Nose and Mouth, and holding his Breath for a while, to cause the Matter to run out: Then the Dura Mater may be wip'd with Lint; but if any Pus or corrupt Matter lies underneath, it must be pierc'd with a Lancet wrapt up in a Tent, that it may not be perceiv'd by the Assistants. Afterward a Sindon or very fine Linnen Rag dipt in a proper Medicament, is put between the Dura Mater and the Skull; the Hole is fill'd with small Bolsters steept in convenient Medicinal Liquors; and the Wound is dress'd with Pledgets, a Plaister, and a Kerchief.
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
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.