NAVICULAR DISEASE. 311 



out them, and his feet are frequently pared out, and the quarters 

 lightly rasped. In five or six months the horn will generally have 

 grown down, when he may be talfen up, and shod with shoes un- 

 attached by naUs on the inner side of the foot, and put to gentle 

 work. The foot wiU be found very considerably enlarged, and 

 the owner will, perhaps, think that the cure is accomplished. 

 The horse may, possibly, for a time stand very gentle work, and 

 the inner side of the foot being left at liberty, its natural expan- 

 sive process may be resum.ed : the internal part of the foot, how- 

 ever, has not been healthily filled up with the expansion of the 

 crust. If that expansion has been effected forward on the quar- 

 ters, the crust will no longer be in contact with the lengthened 

 and narrowed heels of the coffin-bone. Thore will not be the 

 natural adhesion and strength, and a very slight cause, or even 

 the very habit of contraction, will, in spite of all care and the 

 fireedom of the inner quarter, in very many instances, cause the 

 foot to wire in again as badly as before.* 



THE IfAVIOULAR-JOINT DISEASE. 



Many horses with weU-formed and open feet become sadly and 

 permanently lame, and veterinary surgeons have been puzzled to 

 discover the cause. The farrier has had his convenient explana- 

 tion " the shoulder ;" but the scientific practitioner may not have 

 been able to discover an ostensible cause of lameness in the whole 

 limb. There is no one accustomed to horses who does not recol- 

 lect an instance of this. 



By reference to e, Fig. 37, it will be seen that, behind and 

 beneath the lower pastern-bone, and behind and above the heel 

 of the coffin-bone, is a small bone called the navicular or shuttle- 

 bone. It is so placed as to strengthen the union between the 

 lower pastern and the coffin-bone, and to enable the flexor tendon, 

 which passes over it in order to be inserted into the bottom of 

 the coffin-bone, to act with more advantage. It forms a kind 

 of joint with that tendon. There is a great deal of weight 

 thrown on the navicular-bone, and from the navicular-bone on 



* I^ote by Mr. Spooner. — A vast amount of error has beetf writtec in 

 vai ious books with regard to the subject of contraction. For our own 

 parts, we believe that it is in the greater number of instances the conse- 

 quence rather than the cause of lameness ; and the dissection of a great 

 number of diseased feet, 1^ assured us that when lameness is present 

 there is disease of the navicular-joint, of the pressure of which there cannot 

 be better proof than the symptom of pointing alluded to in the text. It 

 ia quite true that some horses will point from gait or habit, without any Jis- 

 ease being present ; but when lameness exists, and the horse also points, 

 we may take the latter symptom as presumptive evidence tliat the case ia 

 une of navicular-joint disease. 



