SYMPTOMS OF VAEIOUS DISEASKS AFFECTING THE FEET. 333 



In cases of long standing, the inside quarter of the foot will become 

 straighter, and there will be small circular ridges on that part of the hoof. 

 The horn of the sole will also be found to be increased in quantity, the 

 sole will be more concave than natural, and the feet generally will be 

 more upright, blocky and contracted. From saving of the back part of 

 the foot and consequent absence of pressure on the frog, thrushes will 

 probably make their appearance. Navicular disease may and very often 

 does appear in good open feet, but gradually the above changes will take 

 place. Tenderness will be evinced on the application of concussion to the 

 heels, or at the point of the frog. A further test may be applied by 

 bending up the foot and applying pressure by the thumb to the hollow 

 of the heel. The seat of the disease will be nearly under the thumb. 



The lameness is most apparent when the horse first comes out of the 

 stable. It decreases with exercise. Nevertheless, on the day after severe 

 work the horse will be more lame than usual, especially when going down 

 hill. In doubtful cases, therefore, the animal should be subjected to 

 strong work, and examined again after a night's rest. 



665. Symptoms of Ossified Cartilages. 



Ossified Cartilages, commonly called Side bones, are not uncommon in 

 the fore feet, especially in underbred horses. They may occur, though 

 but rarely, in the hind feet. They generally produce a want of elasticity 

 in the tread rather than positive lameness. Their existence is easily de- 

 tected by feeling the cartilages at each side of the heels. In health they 

 are flexible, but in disease they become more or less ossified and inelastic. 

 See also par. 634. 



666. Symptoms of Thrush. 



This disease is generally perceptible both to the eyes and the nose. 

 In cases of doubt it is advisable to pare off the outer coat of the frog, as 

 extensive disease may exist under an apparently almost sound exterior. 



Thrushes in an otherwise good foot will not cause a horse to go lame 

 unless he happens to tread on a stone, or otherwise bruise the diseased 

 structure. 



667. Symptoms of Canker. 



Canker is a fungoid disease of the sole, commencing generally at the 

 point of the frog, but is not, as a rule, in any way connected with thrush. 

 This fungoid growth exudes a thin, unhealthy discharge, and bursts upon 

 the slightest exciting cause. In the latter stages this diseased condition 

 is apparent enough. 



668. Symptoms of Corn. 



The seat of Corn is at the inner angle of the sole in the space bounded 

 by the crust and its reduplication (the bars). The existence or otherwise 

 of a Corn can always be at once detected by paring off the surface of the 

 sole at the part indicated. See par. 1009. 



