602 THE DISEASES OF THE HORSE 



forms. Tliis can only bo done l^y probing ; and if tho original oponing is 

 in tlie coronet, the probe must be passed down as low as possible, and then 

 the sole should be pared away till the end can be reached. In tolerably 

 i-econt quitlors, this plan alone will allow the sinus to heal : but in old ones, 

 the internal surface has become callous, and no granulations are thrown out. 

 Here an injection should be thrown in every day with a syringe, a saturated 

 solution of sulphate of zinc being that generally recommonded ; but I have 

 found the chloride answer still better, using one drachm of the salt to a 

 pint of water at first, and going on up to two drachms. By injecting this 

 daily, and introducing a piece of lint, wetted with it, into the superior 

 opening, leaving the lower one free, I have cured many bad quittors, even 

 when there was evidence of caries of the cottin-joint. The disease requires 

 a careful adjustment of the remedies to its extent and nature, and a 

 theoretical description of it is of little use. 



THRUSH 



Any offensive discharge from the frog is called by this name, although 

 the cause and treatment may be as difTorent as possible. It varies greatly 

 in the fore and hind feet ; and, indeed, it must never be forgotten that, in 

 every case, the cause which has produced the discharge must be clearly made 

 out before any plan of treatment can be carried out with any prospect of 

 success. Sometimes thrush is merel}' the result of the decomposition of the 

 horny frog, from the foot being constantly kept wet with urine, which is 

 most common in the hind-foot. Here the surface becomes soft, and is 

 gradually dissolved : while the cleft, from its retaining tho moisture, is 

 increased in size. This state is often brought on by the too frequent use of 

 cowdung-stopping in horses with soft frogs ; and, instead of doing good by 

 his treatment of the foot, the groom is really destroying it by encouraging 

 the decomposition of the healthy defence which Nature has given to it. For 

 this kind of thrush, very little treatment is required if the cause which 

 produced it is withdrawn. Still, it is not always easy to keep the frog 

 dry, and stop the decomposition, without the application of some astringent; 

 and if the mere use of dry litter, and the application of tar ointment, do not 

 seem to harden the frog at once, it may be touched with a wash composed 

 of ten grains of bluestone to the ounce of water. This will soon dry it ; or, 

 if it fails by any chance, the chloride of zinc may be used in the same way, 

 by dissolving five grains in an ounce of water. 



The second kind of thrush is that in which from a gross habit of body 

 there is a simple inflammation of the sensible frog, and instead of sound 

 horn being secreted, a spongy substance is deposited, which breaks away in 

 places, and the frog looks ragged and uneven, with a greasy surface, smells 

 very foul, and fe^Is hot to tho touch. Here the trenlmont must be general 

 as well as local. A dose of physic should be given, tho food should be of a 

 less stimulating quality, and care should be taken that regular exercise is 

 allowed every day. The stable should be kept cool, and of course attention 

 .should be paid to the cleanliness both of the food and the litter. As to 

 local remedies, they must not be of the stimulating kind which will suit the 

 thrush from decomposilion, or that presently to be described. The foot 



