134 EXAMINATION OF HORSES 



account no doubt of its puffy, boggy feel. Bog-spavin 

 may be due to 



1. Habit of the secreting membrane. 



2. Formation of the hock. 



3. Disease in the joint. 



So that you see it may be an unsoundness, or it may 

 not. When a joint works at a disadvantage, no matter 

 from what cause, it requires more lubrication. If this 

 disadvantage arises from conformation, it is evident that 

 it is permanent, so that the hock will always require 

 more lubrication ; and as you know, there are few parts 

 of the body which do not yield in response to extra 

 calls upon their powers, whether it is a muscle that has 

 to lift more weight, as the blacksmith's biceps ; a skin 

 that has to stand more pressure, as a blacksmith's hoofy 

 hand ; or a membrane that has to endure more friction, 

 as the synovial membrane in question. In this case 

 then you have to determine upon the cause that is 

 giving rise to the increased supply of oil, and if there 

 be no actual disease present, which cannot fail to be in- 

 dicated by lameness, but only mechanical disadvantage, 

 he may be quite sound, however long he may remain so, 

 with which you have nothing to do. 



Formation of hock has much to do with an appear- 

 ance of bog-spavin. It is self-evident that, in a ve-ry 

 straight hock, the ends of the bursa will be wider apart 

 and the bursa stretched more than in a bent hock. In 

 the bent hock there is, as you see by the diagram 



