COMPLICATIONS—­(a) Necrosis of the Lateral Cartilage.—­This is the so-called ‘cartilaginous quittor’ of other writers.  In all probability it is the condition generally understood when the word ‘quittor’ is used by one practitioner to the other.  Its tendency to keep the disease existing in a chronic form renders it of grave importance, and for that reason we give it first mention among the complications.

It may occur as a sequel either of cutaneous or of sub-horny quittor, and may result either from actual wounding and infection of the cartilage, or from an attack on it of septic matter originating elsewhere.

Unless there has been discovered a fistula, which on probing is seen to lead direct to the position in which we know the cartilage to be, we know of no precise means by which the existence of this condition may be diagnosed.  When free from other complications, the horse with his foot in this state may travel fairly sound.  This is so when the necrosis is situate in the posterior half of the cartilage, in which case the irritation set up by the disease is confined to the comparatively non-sensitive tissues of the cartilage itself and the fibrous mass of the plantar cushion.  When attacking the anterior half of the cartilage, the close contiguity of the joint renders the disease of a more serious nature.  It is then that we have acute pain, and with it extreme lameness, for in this position it is more than likely that we have involved either the synovial membrane of the articulation or the tops of the sensitive laminae.  It will be remembered that here the synovial membrane protrudes as a small sac between the antero- and postero-lateral ligaments of the joint.  More or less easily then it is bound to come into intimate contact with the septic matter attending the necrosis of the cartilage, and so share in the inflammatory processes, afterwards communicating them to the interior of the articulation.

With necrosis of the lateral cartilage is always swelling and thickening of the skin and subcutaneous structures of the coronet.  This is the greater the longer the disease has been in existence.  Upon the swelling is seen the mouth of the fistula, or it may be the mouths of several, and from them all a discharge of pus.

The mouth of each fistula is generally filled with a mulberry-like granulation tissue, standing above the level of the skin, and bleeding easily if touched.  The exuding pus is thin and pale gray in appearance, gritty to the touch, and generally free from pronounced smell.  At other times its colour is reddened with contained blood, and floating in it are tiny particles of a pale-green substance, which when picked up and rubbed between the fingers are seen to be small fragments of the diseased cartilage.

Should the mouth of a fistula become occluded with the granulations filling it, and the discharge prevented from escaping, it soon happens that we have close to the fistula that has closed a tender fluctuating swelling.  This points and breaks, and pus is again discharged from another opening.  In this manner is accounted for the multiplicity of scars and fistulas seen on the swelling of an old-standing quittor.