OSSIFIC DISEASE OF JOINTS. 57 



which it is found growing. When horses, however, come to 

 be worked, to have their joints sprained or otherwise injured, the 

 inflammation consequent thereon, Z5, as has been already shewn, 

 the ordinary precursor of exostoses occurring upon them, or in their 

 immediate vicinity. 



Exostoses occasion Lameness or not, according to the 

 condition, inflammatory or not, of the nidus of callus in which they 

 are forming, as well as the condition, stretched or inflamed, of their 

 periosteal tunics. In general, we know that horses do not go lame 

 from splents; we also know that bone spavin, frequently, of 

 large size even, is present without occasioning lameness. On 

 the other hand, simply a "knot" in the spavin place now and 

 then evidently causes lameness. All this, we repeat, will depend 

 upon the condition, at the time, of the callus and of the periosteum ; 

 though in the case of spavin in particular we must take like- 

 wise into consideration the interference of the tumour with the 

 action of any tendon or joint, as well as any participation of the 

 latter in the diseased action. The extreme soreness which now 

 and then is manifested by horses whenever exostoses of which 

 they are lame are felt or pressed, arises from an inflamed and 

 morbidly sensitive state either of the callus or of the periosteum, 

 or of both. 



The Treatment of Ossific Disease of the Joints will be 

 best considered under the respective heads of particular lamenesses 

 arising therefrom. We shall find it a form of disease which, so 

 far as joints are concerned, is, as we have before observed, frequently 

 complicated with ulceration of the articular cartilages ; which con- 

 sideration it is that has induced us to take general views of both 

 diseases before we proceed to treat of their special forms, under 

 the appellations of spavin, navicular-joint disease, knee-joint dis- 

 ease, &c. 



VOL IV. 



