AS TO SOUNDNESS. 



almost always in the epiphysal cartilage at the lower 

 end of the femur in young men and women at a time 

 — according to anatomical text-books — when the epi- 

 physal cartilage is being converted into bone (Gray 

 gives it at the twentieth year). We could easily multiply 

 these examples, but you will already have learned the 

 fact as one of the fundamental principles in physiology- 

 Then if you find that these bones have little movement 

 one on the other, and have a tendency to become con- 

 solidated, as has been abundandy proved ; and that 

 during the process of consolidation the functional 

 activity of their nutrient parts is intensified, and that 

 under full functional activity a part is soon thrown into 

 a state of disease, — I say, if you grant all this, why need 

 we look for ''concussion" acting upon healthy bones 

 as the cause of spavin, as is usually done? You will 

 perhaps have heard of the theory that spavin is produced 

 by the concussion to which these parts are subjected 

 when the horse sets his foot down, and that it occurs 

 on the inner rather than on the outer side, because the 

 inner side is more under the centre of gravity. Now 

 this is just nonsense. Look at any hock, and you will 

 find that the direction of weight is from within outwards, 

 and not from without ifiwa?'ds. This is evident to all 

 who examine the hip joint, also direction of the articular 

 surface of the astragalus ; but most evident of all when 

 you watch a horse that is either standing or moving. 

 Gentlemen, spavin is caused by concussion, but it is 

 the concussion of extreme flexiori ; and this is why we find 



