•210 THE PRACTICE OF VETERINARY MEDICINE. 



effect a cure, throws out an exudate which, becoming ossi- 

 fied, firmly unites the diseased osseous structures, constitut- 

 ing anchylosis, which, when completed, is usually followed 

 by cessation of irritation, etc. The inflammation is set up 

 in the cancellated tissue, but extends to and involves the 

 articular lamellae, which gradually undergo destruction, 

 and anchylosis, as described above, finally occurs. As 

 a rule, there is no enlargement to be seen in connection 

 with high spavin ; any enlargement that occurs being 

 seen usually in connection with low spavin. The high 

 spavin is usually associated with caries of the articular sur- 

 faces of the bones, and destruction of the articular carti- 

 lages. In some cases the ossific matter is deposited between 

 the bones, and not the slightest external enlargement can 

 be discovered. On the other hand enormous deposits, ex- 

 tending completely around the articulation, are often met 

 with. So long as the true articulation escapes, the animal 

 may go comparatively sound ; after the hock has once suf- 

 fered from spavin, it can never be restored to its natural 

 condition. There are many nostrums sold for the purpose 

 of removing and curing spavin ; but such an object cannot 

 be eff'ected by any power with which we are acquainted. 



Causes. — The causes of spavin are predisposing and exciting. 

 The predisposing causes are, an hereditary tendency — heavi- 

 ness of body, especially when such a body is associated with 

 light limbs ; and in some cases there may be an ossific dia- 

 thesis. Certain conformations predispose, as that of a horse 

 possessing weak hocks and abnormally long metatarsal bones, 

 .such a horse being considered to be more liable to spavin 

 than a horse of diff'erent conformation. A horse having a 

 hock narrow from before backward is also considered to be 

 predisposed. The exciting causes are hard and fast -work. 

 In the case of an injury to one of the hind limbs, causing 

 the animal to stand upon the sound limb, the latter be- 



