NAVICULAR DISEASE. 335 



and the animal may be sound. Again, botli fore feet are 

 sometimes apparently contracted without lameness, but if 

 examined closely, they will be found to be small and not con- 

 tracted ; the bones of the limbs will participate in the peculi- 

 arity of conformation ; they will be narrow from side to side, 

 and in all probability the hind feet will be small also. The 

 contraction of the feet due to navicular disease wiU be found 

 in the foot or feet that are lame, and it is an atrophied con- 

 dition, resulting from diminished function, disappearing by 

 degrees if the original disease, or the pain resulting therefrom, 

 can be eradicated ; for example, if the original freedom of action 

 is restored to the parts by neurotomy, the disease still being 

 present, the foot or feet contracted will regain their original 

 dimensions. 



II. Sprain or Laceration of the Fibres of the Perforans 

 Tendon. — This was the theory taught by Professor Dick, and 

 accepted by myself and the great majority of his pupils. He 

 said — " I have endeavoured to demonstrate that primary and 

 permanent disease is established in the synovial capsule, between 

 the tendon and navicular bone, and arises from strain and over- 

 extension of the tendon, where it passes under the navicular bone. 

 It has predisposing causes, such as want of paring, shoeing, and, 

 still more, bad shoeing ; hereditary tendency of particular breeds, 

 and high condition, for it is a disease rarely of the agricultural, 

 but of the high-bred horse. In like manner, it has manifest 

 exciting causes, such as strain of the tendon and over-exertion, 

 pressure on the sole, as from travelling with a stone in the foot ; 

 and there is the tight shoe, exciting irritation of the foot, 

 which, hot and uneasy in the stable, is aggravated by occa- 

 sional and violent exercise." Towards the end of Professor 

 Dick's career, the idea that the disease was due to laceration of 

 the tendon became more firmly held by him, and that this was 

 caused by bad shoeing, that is to say, by allowing the toe of the 

 foot to be too long, and applying a shoe, thick and irregular at 

 the toe, which, by increasing the resistance of the foot, when 

 implanted upon the ground, to the action of the flexor muscles, 

 threw an additional strain on the tendon where it passes under 

 the navicular bone. 



During the last five years I have made numerous post m&rtem 

 examinations of navicular disease, and am convinced that strain 



