636 Journal of Agriculture. [8 Oct., 1907. 



structure, and to perforin its function as an elastic wedge to lessen con- 

 cussion and maintain the heels apart. If, however, the frog is raised 

 off the ground it ceases to perform its wedge function, and commences to 

 atrophy and contract, the contraction being largely brought about by the 

 side pressure of the heels. As it contracts the heels become approxi- 



mated and curled in, so much that the frog may be lost to view. If, 

 on account of the existence of pain, as in navicular disease, or for any 

 other reason, the horse goes on his toe, there will be loss of frog 

 pressure and liability to contracted heels. Sometimes actual lameness 

 results, in which case the condition is an unsoundness {vide Greenway v. 

 Marshall, Baron Pollock, Eng., 1845); and in most cases there is loss 

 of freedom of movement proportionate to the extent of the contraction. 



Treatment. — The remedy lies in proper and skilful shoeing, whereby 

 the frog pressure is continuously maintained. In the early stages benefit 

 may result l)\ running the horse at grass unshod for a few months, or 

 if work has to lie continued an artificial rubber frog pad fixed to a 

 leather sole mav be used. There are many such frog pads patented. 

 If the condition is at all advanced, and the frog much shrivelled, there 

 is little likelihood of a cure, but the constant aim ought to be to have 

 the foot so shod that the frog will come to the ground. 



Thrush. 



Thrush is the term given to a condition in which there oozes from the 

 horn and fissures of the frog a foul -smelling irritant discharge. The 

 condition is really one of inflammation of the horn secreting (keratogenous) 

 membrane of the frog, whereby a softened and degenerated horn is 

 formed, instead of the tough elastic horn which is natural as a covering 

 of the frog. The altered horn has a cheese-lilie consistency, lacks 

 coherence, and can be easily scraped off with the thumb nail or any 

 blunt instrument; in severe cases it rots off completely, leaving the 

 vascular tissues exposed and raw, so that rough contact causes them to 

 bleed and ulcerate. 



Thrush is an unsoundness, vide Barrett v. Preece, Shrewsbury County 

 Court (Eng.), 1858. 



Causes. — The most potent cause of thrush is exposure of the frogs 

 to filth and damp. Neglect to remove the " balling " of horse dung 

 or soiled bedding, tan, or sawdust from the shod foot is a fruitful source. 

 Such substances quickly undergo a moist fermentation, whereby solvent 

 fluids are formed, which at first moisten the horn and destroy its texture, 

 and afterwards penetrate and inflame the sul^iacent tissues. Hence 

 horses kept in filthy stables are most liable to thrush, and the hind feet 

 are more often affected than the fore, because of their more continuous 

 liability to contact with urine and dung. Paring of the frogs by 

 farriers doubtless acts as a predisposing cause, both because of the ex- 

 posure of immature horn and the abolition of frog pressure. The per- 

 nicious practice of " stopping " the feet with cow-dung or such like 

 decomposable material is also responsible for many cases of thrush. 



Treatment. — Diseased or loose portions of horn should be removed, 

 and the degenerated horn scraped off. Then some drying and disin- 

 fectant dressing should be applied to the surface, and pressed into the 

 fissures two or three times a day until the discharge ceases, and a healthy, 

 natural-smelling horn growth is brought about. Calomel and powdered 

 inirnt alum are useful agents for this puri)ose, or an antiseptic wound 



