LV. If the Caries is in the greater Bones, and lyes deep, or is subject to the inflowing of Matter; the readiest way will be by Ma∣nual Operation, viz. either by Instrument, or the Actual Cautery.
LVI. If you can easily come at the Bone to scrape it, as in the Cranium, that way will be most proper: and you are to scrape 'till you find it firm, and that you discern ruddiness in the Bone, and not only 'till it looks white, for that is the natural colour of the outward Cortex or Shell.
LVII. Yet in some it is frequently found porous and carious, whil'st it retains that colour; and if you do not rasp, scrape, or pare that away, the Callus will be slow in thrusting out, and putting off the rotten part: and if you do scrape it, the deeper you enter into it, the browner and softer the Bone will be.
LVIII. But you ought to be cau∣tious in the Work, that you pene∣trate not to the Marrow of the Bone; when possibly you need not take away more than the external Shell of it.
LIX. The Bone is to be scraped, (if the corruption of it is small) with an Instrument for that purpose, called the Scraping-Instrument: or, (if the corru∣ption and foulness is great) by rasping it with a Raspatory, or by shaving, or paring it with a Chizel; or else by perforation of it with a Wimble, or Auger, or Terebellum.
LX. If you do it with the Chizel and Mallet (a Leaden one will be best) the Bone is then to be made smooth and even with a Raspa∣tory: this being done, some of the aforegoing Medicaments, or some drying Sarcotick must be applied, according to the Con∣stitution of the Patient, by which you ought to be guided.