BOOK VII. 4. 1-3

the same way with the probe and knife; so also when they present multiple branchings. When the end of the fistula is reached, all the callus hardened tissue should be cut out, then pins original: "a" are inserted through the skin margin, and agglutinating medicaments spread over all. But if it runs straight inwards, after its chief direction has been explored by means of the probe, that cavity ought to be excised, then a pin is to be inserted through the skin opening, and agglutinating medicaments applied as above; or if there is more corrupt ulceration, which is at times the case when there is disease of bone, after the bone original: "b" has been treated, suppuratives are put on.

Now it is common for fistulae to have their exit between ribs; when this is the case the rib must be cut across on either side at that spot, and the segment removed lest anything diseased be left within. Fistulae which have passed between the ribs often involve the transverse septum original: "c" the membrane separating the viscera above from the intestine. This can be recognized by the position of the fistula and the severity of the pain, and because at times, air with frothy humour escapes from the fistula, especially when the patient has held his breath. In that case there is no opportunity for the medical art. But in the case of other fistulae near the ribs which are curable, greasy medicaments are objectionable but anything else which suits wounds may be used; the best, however, is lint put on dry, or after soaking in honey if anything has to be cleaned.

There is no bone in the abdomen, but all the same fistulae there are so dangerous that Sostratus thought them incurable. Experience, however, shows that this is not always the case. Indeed—and this may