When the fistula by time becomes callous (and it is impossible to be mistaken in a callosity, because it is hard, and either white or pale) then there is a necessity for stronger medicines. Such as that composition, which contains of poppy tears p. i. *. gum p. iii. *. cadmia p. iv. *. copperas p. viii. *. these are incorporated with water, and made into a collyrium. Or that, which consists of galls p. i. *. verdigrease, sandarach, Egyptian allum, each p. i. *. calcined copperas p. ii. *. Or that, which is composed of chalcitis and stone-lime, to which is added of orpiment less by one half than each of the other ingredients; and these are mixed up with boiled honey. The most expeditious is the prescription of Meges: to reduce to powder of rasile verdigrease p. ii. *. then to dissolve in vinegar, of ammoniacum thymiama p. ii. *. and with this to bring the verdigrease to a consistence: and this is one of the choicest medicines. But though the foregoing compositions are the most efficacious, yet if these are not to be had, it is easy to destroy the callosity by some caustic medicines: and it is sufficient to arm with these a twisted paper reed, or some part of a penecillum, formed after the manner of a collyrium. Squills also boiled, and mixed with lime consume a callus. If the fistula happen to be pretty long, and transverse, after introducing a probe, it is very proper to make an incision over against its origin, and to put in any collyrium you chuse. But if we judge the fistula to have two or more sinuses, provided it be short and confined to the flesh, we ought not to make use of a collyrium, which may cure one part, and not touch the rest; but the same medicines dry are to be put into a writing reed, which being applied to the orifice, the medicines must be blown into the fistula. Or the same things may be dissolved in wine; or if the fistula be somewhat foul, in mulse; if somewhat, callous, in vinegar; and whatever is injected, must be infused in this liquid form. Coolers and repellents must be applied above; for generally the parts about a fistula are a little inflamed. Neither is it improper, when one has removed the dressings, before he make another injection, to wash the fistula by means of a syringe; if there be much matter, with wine; if the callosity be pretty hard, with vinegar; if it is already cleansing, with mulse, or a decoction of vetches in water, with a little honey added to it. It commonly happens that the membrane, which is betwixt the orifice and the sound flesh, being overcome by so many medicines, casts off, and the ulcer is clean below. Whenever this happens, agglutinants are to be applied, and especially spunge armed with boiled honey. I know it is a practice approved of by many in this case, to have lint rolled up into the form of a collyrium, and dipt in honey, introduced for incarning. But this method more quickly agglutinates, than incarns. And there is no fear, that clean flesh brought into