428 DISEASES OF THE HORSE'S FOOT 



the bursa itself, the perforans tendon, or the navicular 

 bone, and characterized by changes in the form of the hoof 

 and persisting lameness, The disease is commonly noticed 

 in thoroughbreds or in horses of the lighter breeds, and is 

 but seldom observed in heavy cart animals. Usually it is 

 met with in one or both fore-feet. Although of extremely 

 rare occurrence, it has been noticed in the hind. 



History. — To English veterinarians appears to belong the 

 credit of discovering navicular disease. As early as 1752 

 we find one, Jeremiah Bridges, in { No Foot, No Horse,' 

 drawing attention to ' coffin-joint lameness,' and advocating 

 for its treatment setoning of the frog. It appears, too, 

 that Moorcroft, prior to his departure for India in 1808, 

 was acquainted with what was then known as cofnn-joint* 

 lameness, having drawn attention to it in 1804 in a letter 

 to Sir Edward Codrington.+ In 1819 Moorcroft made 

 it even plainer still that he was fully acquainted with what 

 we now know as navicular disease. This we learn from 

 a letter written by him to Sewell, in which he laid claim 

 to being the originator of neurectomy. In this letter he 

 says : 



' On dissecting feet affected wtih these lamenesses, the 

 flexor tendon was now and then observed to have been 

 broken, partially or entirely, but more commonly to have 

 been bruised and inflamed in its course under the navicular 

 or shuttle bone, or at its insertion into the bone of the foot. 

 Sometimes, although seldom, the navicular bone itself has 

 been found to have been fractured ; at others its surface 

 has been deprived of its usual coating, and studded with 

 projecting joints or ridges of new growth, or exhibiting 

 superficial excavations more or less extensive. 't 



Pathology and Point of Commencement of the Disease. — 



The exact position in which the diseased process starts has 



for a long time been a subject of discussion, and even now 



it is doubtful whether the joint has been definitely settled. 



To mention but a few among many : We find Mr. Broad, 



of Bath, strenuously insisting on the fact that the disease 



* The coffin- joint at this time included the navicular bursa. 

 t Percival's ' Hippopathology,' vol. iv., p. 132. X Ibid. 



