THE HOESE AND ITS DISEASES. 67 



parts adjoining the ix)wel swell, and, at the end of that 

 time, there appears a discharge of yellowish matter, 

 which gradually becomes thicker and whiter in three 

 days, at farthest ; the part must be examined, and the 

 plug removed from the hole to allow the matter to flow 

 out. The rowel is now complete, and may be continued 

 as long as found necessary. The action of the rowel is 

 easily explained — the leather introduced excites a degree 

 of inflammation between the skin and flesh, and by no 

 means taken to check this, it goes on like most other 

 inflammations of fleshy parts to suppuration ; thus a 

 discharge is produced from the part, which is found to 

 have considerable eff'ect in checking inflammation of 

 some more important organ near which the rowel has 

 been inserted. 



Setons. 



Setons are very useful to drain off matter gradually 

 from large abscesses, or suppurating tumors. It is a 

 piece of cord or tape passed thi^ough the base of such 

 ulcers as have deep sinuses between the skin and muscles. 

 This is effected by means of an instrument resembling 

 a needle, and the seton is kept in its place by tying both 

 ends together. The tape should be moved several times 

 during the day, and wetted with turpentine, spirits of 

 wine, or some acrid liquid, in order to keep u^) the 

 inflammation, and promote the discharge of matter, 

 which is the purpose for which setons are used. 



Setons are often useful in increasing a discharge in 

 the places contiguous to inflammation, and thus carrying 

 ofl" th it superfluity of fluid matter which would distend 

 the vessels of those parts, and keep up the inflammation ; 

 for example — in inflammation of the eye, a seton in the 

 cheek will act with much advantage, on the principle of 

 counter irritation. In deep-seated inflammation, many 

 favourable results have been experienced in the use of 

 the setons ; for example — in inflammation of the navi- 

 cular joint, great advantage has been derived from a 



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