(c) Caries of the Bones. - Portions of the os pedis, more especially of its wings, and therefore usually occurring in conjunction with necrosed cartilage, become carious in quittor. In many cases it is impossible to say with certainty when this has occurred. In a few instances, however, the exuding discharge gives evidence of what has happened. It is thin, but extremely offensive, with the characteristic odour of decayed bone or tooth, and with a feel that is gritty with contained particles of broken-up bone. If, with a discharge of this nature present, the probe also conveys to the fingers the sensation that bone is reached, then diagnosis may be sure.

(d) Ossification of the Cartilage. - This may take place in part or in whole. It, of course, constitutes Side-bone, a fuller description of which will be found in a later portion of this chapter.

(e) Penetration of the Articulation. - This may occur either as a result of the suppurative changes or as an accident in excision of the diseased cartilage. Unless it is followed by a severe purulent arthritis, it is not so grave a complication as at first sight it would appear.

(f) Synovitis and Arthritis (Purulent). - Should this complication arise, the case is a most serious one. Beyond here mentioning the fact that it may occur, we shall not dwell on it. Fuller consideration is given to it in Chapter XII (Diseases Of The Joints[A]).

Treatment. - The various treatments adopted for the cure of sub-horny quittor offer the veterinary surgeon a large number to select from. We will describe them in the order in which they are, perhaps, most commonly practised.

Poultices and Hot Baths. - As in cutaneous quittor, and as in coronitis, when the pus formation is only suspected, and has not yet broken out at the coronet or elsewhere, then the first indication in treatment is the use of warm poultices or of hot baths. Their application is in most cases productive of pointing at the coronet.

Directly this appears it is a wise plan to thin the wall down with the rasp immediately below the swelling. To some extent it relieves the pressure of the inflammatory products within, and at the same time paves the way for operative measures which may be necessary later on.

With the breaking of the abscess and the discharging of its contents, we may in some measure ascertain the condition we have to deal with. The probe is used, and the abscess cavity explored. The size of the wound, its depth below the upper margin of the wall, the structures involved, and other information, may be thus obtained.

At first, however, the nature of the wound, and the character of the discharges, must largely guide us as to the treatment we adopt. In many cases, even where the abscess cavity is far below the upper margin of the wall, and is presumably in an unfit position to drain and heal, a a regular application of an astringent and antiseptic dressing is sufficient to bring about resolution. If, however, the discharge from the wound continues to be liquid, and the wound itself at one spot refuses to heal, it may be judged that a portion of necrotic tissue is situated under the wall, and affecting the laminae, the cartilage, or ligament, as the case may be. If this is so, then operative measures must be determined on (see Removal of the Wall, p. 349).

Blisters. - Instead of the poultice and hot baths, the pointing of the abscess and the casting off of the slough may be brought about by the application of a sharp cantharides blister. We have, in fact, seen many cases where this treatment was adopted prior to the formation of a fistula, and also in cases where one or more fistulous openings already existed, where repeated blisters to the coronet have alone been sufficient to effect a cure.

We are bound to admit, however, that the treatments of poulticing and blistering are only expectant - we might almost say empirical. At any rate, we admit to ourselves that what we have advised and carried out is not in itself curative, but only a means of assisting Nature to satisfactorily work her own ends. Empirical or not, however, we believe that in every case of quittor it is wise in practice to at first adopt some such simple measure, for in nearly every instance where operative measures are practised, the patient must be laid aside for at least several weeks, whereas in this way he may be kept at work and a cure effected at the same time.