DISEASES OF DOMESTIC ANIMALS. 139 



Flemmings thinks it commences in the tendon. I believe it may com- 

 mence in either of the three, and if it comes on slowly, it begins in 

 the bone or bursse ; but if it is suddenly produced, it begins in the 

 tendon ; for we find that after a punctured wound in the foot, it is 

 sometimes the case that the animal remains lame from navicular 

 disease. It is then in most cases the result of inflammation in the 

 cancellated structure of the navicular bone, which extends and inter- 

 feres with the nutrition of the articular cartilage, giving rise to caries. 

 The bursa is destroyed and the tendon becomes attached to the bone. 

 The tendonous fibres may become destroyed to some extent, which 

 accounts for the tendon giving way after neurotomy. Contraction of 

 the foot may be caused by a slight irritation of the sole, and sensitive 

 laminae, and it is difficult to say whether it is this or navicular disease, 

 until after a time the symptoms become plain, ii it is navicular disease. 



Causes. — Hard and fast work are the exciting causes. In some ani- 

 mals there is an hereditary tendency — a short upright pastern, with a 

 stubby, imperfect action, and a very high action, which pounds the 

 ground ; allowing the toes to grow too long, cutting down the heel at 

 every shoeing, etc. We find it is rare in racing,hunting, and even in the 

 trotting horses, so long as they are used upon the turf, although they are 

 subject to hard and fast exertion, for they are shod so as to keep the feet 

 in a natural shape. But when they are shod with high heels and toes, 

 and are driven upon hard roads, then they are liable to have navicular dis- 

 ease. Injury to the perforans tendon and irregular exercise tends to 

 produce it. 



Symptoms. — There is usually more or less lameness — very sudden 

 and severe in some cases, in others slight and gradual — and perhaps 

 for weeks or months it may be somewhat transient before it becomes 

 permanent. Just when brought out in the morning he goes lame 

 for a few steps, and then it disappears. He may be used in this 

 manner for some time, and then grow very lame, then navicular 

 disease is well established, the foot is pointed, etc. This may only 

 be a habit, but when a horse has been used moderately, and is in 

 good health, pointing is suspicious, and it may be present for some 

 time before there is any well marked lameness or tenderness. If 

 both feet are affected and he is suffering pain, then he throws the 

 weight first upon one foot and then the other, and when brought 

 from the stable he goes with a kind of groggy action, hence it has 

 been termed grogginess. Another well marked symptom is atrophy 

 of the muscles of the limb, which extends and involves the muscles 

 of the shoulder. This is not sweeney, as it is called, but is the result 

 of navicular disease. There are generally well marked changes — 

 atrophy of the foot and contraction of the hoof — and is easily noticed 

 if but one foot is affected. There are other means of forming an 

 opinion : tap with a hammer over the region of the navicular bursa, 

 and pain is evinced, or press upon the tendon at the back part of and 

 close to the frog. This will assist you, but it is not conclusive evidence. 

 Then there are negative symptoms. In a well marked case of navicular 

 disease tliere is generally a nice clean limb. Look at the manner in 

 which the shoe is worn. If it is navicular disease, it will be worn at 

 the toe, but some horses do this in health more than others, so you 

 must make allowance for it. 



Treatment — If it is of a severe character, and of long standing, 

 perhaps years, then it is incurable. But if recent, in the inflamma- 

 tory stage, of only weeks' standing, or perhaps months', then, a 

 complete cure may be effected. So you must take into consideration 



