542 THRUSH. 



well when shod with leather, and with a shoe shortened at 

 the quarter, which is the seat of corn. By regularly attend- 

 ing to this, horses, before useless, have been able to per- 

 form work with comfort to themselves and satisfaction to 

 their owner. In slight cases of corn, the shoe proper to 

 be used is one of rather more substance than common, 

 with the web a little wider than usual, and its width equal 

 throughout, that is, as wide at the heels as the toe ; it should 

 also extend rather farther back than it generally does, and 

 present a perfectly level surface to the sole. This affords 

 ease and protection : future pressure must be avoided by 

 keeping the seat of corns clear from offending horn. 



THRUSH. 



This complaint consists in a diseased action of the seba- 

 ceous follicles of the sensitive frog, whereby they produce 

 a thin foetid discharge, which escapes out between the cleft 

 of the horny frog. It is very improperly considered by 

 many as a matter of trifling import ; but a little experience 

 only in the diseases of the feet will show that it is by no 

 means so harmless as supposed. Still more erroneous is 

 it to assert that in all cases thrushes do good by cooling 

 the feet. On the contrary, there probably never was 

 a perfectly harmless thrush, or one that could exist long 

 without doing some injury. Various causes produce 

 thrush ; the immediate one is always inflammation of the 

 sensitive frog. In very many instances their origin is to 

 be traced to the application of moisture, particularly of 

 acrid moisture, as that of dung, urine, &c. ; which, soaking 

 the horny frog, at last penetrates it, and then becomes a 

 source of irritation to the sensitive frog underneath. This 

 effect of moisture accounts for the increased tendency of 

 thrushes to af!ect the hinder feet, while the fore feet remain 

 perfectly free from them. Navicularthritis is notoriously 

 a common cause of thrushes ; when the disease has termi- 

 nated the thrush ends, but the narrow small hardened frog 

 remains. While navicularthritis exists, however, thrush 

 is constantly present, though in the latter stages it may 

 send forth so slight a discharge as almost to escape 

 detection. 



As navicularthritis is a very common cause of thrush, so 



