220 NAVIX ON THE HORSE. 



served to commence forming immediately in front of the nnion 

 of the head of the S2:)lint-bone with the cannon-bone. This bony 

 tumor may continue to enlarge and extend until it has involved 

 the smaller wedges, which lie nearest its origin, thus destroy- 

 .ing the slight motion of which they admitted, and consolidat- 

 ing them with the bones below. Still continuing its march, 

 it next reaches the upper or large wedge-bone, firmly uniting 

 it to those on which it rests. It may also extend round so as 

 to involve the cube-bone, behind. This extensive ossification 

 may have taken place, consolidating the several bones in- 

 volved into one solid bone, as it were, and yet no great degree 

 of lameness be produced, for the motion of which they ad- 

 mitted was but limited. But a more important joint or articu- 

 lation may be reached, that is, the union between the astraffalus 

 and the thigh-bone, which is the most important joint of the 

 hough, being, in reality, the true hough-joint. When this is 

 the case, the lameness is so great as to render the horse entirely 

 worthless. 



It is proper to remark that the same difficulty may arise 

 from inflammation of the ligaments of any of the small bones 

 of the hough; but such cases are certainly rare, the disease 

 almost always commencing at the point indicated. 



I have thus far described the progress of the bony enlarge- 

 ment, which, in size, may vary very gToatly, but which can 

 easily be detected by the eye or the hand. But it must not be 

 forgotten that some horses have naturally very prominent 

 houghs, and it is not at all impossible for a careless or inexpe- 

 rienced observer to mistake an unusually large and rugged 

 development of the heads of the cannon and splint-bones for 

 spavin. But a careful examination and comparison of both 

 legs will prevent such a blunder. When spavin is forming, 

 the first thing that will likely attract attention is lameness, 

 w^hich may be of slight or very serious character. When this 

 is observed, a careful examination will usually detect a degree 

 of heat and tenderness in the region of the inner splint-bone. 



