30 ON THE NAVICULAK DISEASE. 



that the navicular bone, in its descent, must incHne 

 backward, in unison with the motion of the cofTm 

 bone, it follows, that a soft pillow was as much re- 

 quired at the back as at its base : and, indeed, a 

 more extensive one, as the back part of this surface 

 presents a larger space than the inferior. 



Notwithstanding all this difference between the 

 soft bed and the hard one, still it cannot be denied 

 that there are many thousand horses in this country 

 so circumstanced, which travel perfectly free from 

 lameness ; though I much doubt if any one of them 

 retains the full degree of elasticity in action which 

 he originally possessed. 



But the absence of lameness is by no means a 

 proof of the harmlessness of this antecedent dis- 

 ease ; for the navicular joint of such a foot, although 

 sound as adamant, and its surfaces polished like 

 ivory, and duly lubricated with synovia, is in jeo- 

 pardy, and only requires two or three more concur- 

 ring circumstances to effect a lesion w^ithin its de- 

 licate organization ; and this frequently happens 

 instantaneously. 

 Rigidity of foot^ I couccivc that the rigidity of the posterior parts 

 of the foot (the navicular joint not having suffered 

 any injury) conveys to the animal the sensation, not 

 of pain, but merely slight restraint or compression, 

 which is attended with a corresponding want of 

 confidence, that induces him to give an undue bias 

 to the weight towards the toe or front of his foot ; 



