164 



CHAPTER X. 



Diseases and Injuries of the Feet. 



xhhush contracted heels canker sandcback false- 

 quarter split-hoof acute laminitis— chronic laminitis 



sebdt toe ^pumiced feet ^brittle feet inflammation of the 



coronet, ob villitis navicular disease ^horn tumour 



wounds and bruises op the coronet ^pricks in shoeing 



wounds of the sole and fboo corns quittor forging or 



clicking. 



Thrush. 



This is an inflamed condition of the membrajie which secretes 

 the horn of the frog. During the presence of inflammation, this 

 membrane forms weak and degraded horn of cheese-like con- 

 sistence, which readily liquefies under the action of moisture, and 

 produces the characteristic offensive discharge. The longitudinal 

 fissure in the centre of the thick portion of the frog of a foot 

 suffering from thrush (Fig. 48) is caused by the failure of the 

 secreting membrane to produce sound horn. In a healthy foot, 

 the " cleft of the frog " is merely a depression (Fig. 49) in the frog 

 substance, and does not penetrate to the sensitive parts. The iwo 

 great causes of thrush are want of pressure on the frog, and the 

 decomposing effect moisture, laden with fermenting organic matter, 

 has on the frog. The first is greatly aided by the pernicious prac- 

 tices of paring the frog, and using high-heeled shoes ; and the 

 second by the retention of dung and urine in the stall or box, and 

 neglect of frequently picking out the feet of the horses, while in 

 the stable. In India, where the ground is hard, many horses with 

 naturally high heels are very prone to thrush from want of pressure 

 on the frog. Their heels, if not kept sufficiently low, are apt to 

 " wire in," in which case the frog becomes dry and shrivelled up. 

 As the disease advances, fissures, from which a stinking odour 

 issues, occur on the sides of the frog, close to the heel, and the 

 foot acquires a contracted appearance (Fig. 48). In the event of 

 a horse under these abnormal conditions falling lame, an ignorant 



