NAVICULAK-JOINT LAMENESS. 



787 



in the stable is also a fertile source of disease, because the frog be- 

 comes hardened, and does not furnish a soft cushion for the bursa 

 to rest upon." 



I may, in this connection, add that there may be cases of this 

 disease, though somewhat rare, in feet that are weak and thin, 

 which are entirely free 

 from contraction. In such 

 cases it is supposed the 

 cause is owing to the ob- 

 liquity of the joint being 

 so great, that there is ex- 

 cessive play upon the ten- 

 don, the strain upon which 

 produces irritation of the 

 tendon at its connection 

 with the navicular bone; 

 or owing as well to the in- 

 creased action of the joint, 

 irritation of some of the 

 soft structures is produced. 

 It properly comes under the 

 head of Cause of Irritation. 

 But as there may be dan- 

 ger of parties, especially of 

 trotting men, causing di- 

 rect strain and inflamma- 

 tion of the part by lower- 

 ing the heels too much, or suddenly, especially in the feet of 

 horses that are exposed to much strain by being speeded, I will 

 include the following explanations to show the impropriety and 

 danger of doing so. It is stated in the chapter on shoeing, where 

 thin shoes or tips are recommended, that this change must be 

 brought about gradually. When traveling through Vermont, an 

 intelligent trainer, who was a member of my class, wished to 

 know the best method of keeping the feet of horses sound and free 

 from contraction: 



"Keep the adjustment and condition of the feet as nearly 

 natural as possible," I answered, " by using thin steel shoes that 

 will give the frog natural contact with the ground." 



FIG. 693. Tendons and ligaments of the foot. 



