208 DISEASES OF THE FEET. 



because the animals which most frequently contract this disease, 

 do their work at that pace. 



An upright and concave form of foot, with strong heels, is 

 usually supposed to be conducive to navicular disease. As this 

 conclusion has been arrived at in most cases, after the complaint 

 has become fully manifest, and as the peculiar gait of navicular 

 disease induces the shape which in popular opinion confers liability 

 to this ailment ; this supposition cannot be accepted without 

 further proof. 



ALLEGED CAUSES. — Those usually advanced by veterinary- 

 authorities are: 1. Concussion. 2. Sprain of that portion of the 

 perforans tendon which passes over the navicular bone. 3. The 

 employment of high heels or calkins. 4. Compression, through 

 the weight of the body on one side, and the pressure of the 

 perforans tendon on the other. 5. Rheumatism. 6. Heredity. 

 7. Direct injury from stones, nails, etc., " picked up " by the feet. 



1. Concussion. To decide between the respective claims of a 

 number of alleged causes of a disease, it is but reasonable to give 

 priority to the one which is found, most commonly, to affect the 

 sufferers. Harness horses used for quick road work, are, above all 

 other classes, peculiarly subject to this disease ; and owing to the 

 nature of their labour, are proportionately exposed to the ill effects 

 of concussion on their feet and legs ; their feet being especially 

 liable to navicular disease ; and, their legs, to splints. Long 

 journeys, at a fast pace, will make almost any horse groggy. Bad 

 shoeing and want of stable care both help ; but they alone never 

 produce grogginess. The horse must go far and fast ; if his feet 

 be neglected, or shoeing bad, a slower pace and a shorter distance 

 will do the mischief; but there is nothing in the world will make 

 a horse groggy except driving him far enough and fast enough, to 

 alter the synovial secretion of the navicular joint. Cart-horses are 

 quite exempt ; horses working in the omnibuses about Glasgow, 

 always on the stones, and often at ten miles an hour, but nevei 

 more than a mile without stopping, are nearly exempt. The 

 horses most liable are those which work long and fast stages 

 Many tolerably confirmed cases of navicular disease may be 

 hunted, except when the ground be hard, supposing, of course, 

 that tliey are kept off the road ; but no plan of management will 

 enable them to bear the jars incidental to harness work oi 

 hacking. I think that men of experience will bear me out in 

 saying, that the cab horses — which furnish the highest percentage 

 of sufferers from this complaint — of places, in which the roads are 

 laid down with paving stones, are much more subject to navicular 

 disease, than are similarly employed animals in parts where the 



