DISEASES OF THE LATERAL CARTILAGES 339 



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. 



The continued inflammation thus kept in existence has 

 the efi'ect of rendering the skin and subcutaneous tissues 

 in the neighbourhood greatly thickened and indurated. 

 This in time leads to a tumour- like enlargement, and 

 causes the structures of the coronet to greatly overhang 

 the hoof. At the same time the constant inflammation has 

 made its stimulant efl'ects noted in a great increase in the 

 growth of the horn of the wall. 



Although more abundant, however, the quality of the 

 horn is deteriorated. The perioplic ring has become 

 obliterated, and the varnish-like appearance of the healthy 

 wall destroyed. Cracks and fissures in its surface are 

 numerous, and sometimes deep enough to lead to exposure 

 of the sensitive structures beneath, complicating the quittor 

 with a sand-crack of a peculiarly objectionable type. 



Pathological Anatomy of the Diseased Cartilage. — The 

 bulk of observers appear to agree in the statement that in 

 quittor the necrotic cartilage is pea-green in colour, and 

 recognise it by that characteristic. In size the necrotic 

 portion thus recognisable varies from the tiniest speck to 

 a portion the size of a horse-bean. Commonly, however, 

 it is about as large only as a pea. It is seen to be more or 

 less detached from the rest of the cartilage, to which it 

 is adherent by one of its extremities only. In general 

 appearance we can best liken it to the split half of a green 

 pea, whilst others have compared it with the green 

 sprouting of a seed. The portions of cartilage nearest the 

 necrotic piece are also slightly green in colour, thus indi- 

 cating that here also the diseased process has commenced. 

 This peculiar change of colour in the affected cartilage is 



22—2 



