180 VETERINARY MEDICINE AND SURGERY. 



Mercurial ointment 3 i j. 



Oil of cantharides 3 iv. 



Or, if preferred, a seton may be inserted under the skin, entering a cou- 

 ple of inches above the prominence and coming out an inch or so below 

 it. It should be smeared with some blistering ointment, as: 



Powdered cantharides 3 i. 



Lard ! i. 



Firing is considered by some the most efficacious remedy; and, if properly 

 performed, will not leave bad scars — care being taken not to extend the 

 lines to the front of the joint. 



As soon as the process of deposition is completed, whether on the one 

 hand by hastening its full formation, or on the other by checking and 

 limiting the action — the inflammation and pain which accompanied the 

 formation of the exostosis will disappear. The horse will then be lame 

 or sound, according to the position and amount of the new deposit. 

 Commonly the lameness exists only during the formation of the spavin. 

 From two to four months may be required in the treatment. 



Unnerving has been recommended for lameness arising from sjoavin 

 with a view to destroy sensation. The ojDeration, however, is useless, be- 

 cause the nerve which supplies the anterior portion of the hock is so 

 situated that it cannot be reached and divided. It may perhajos be said 

 that the nerve might be cut higher up; but at that point it is too near 

 the muscle which works the tendon. 



In the fore-leg, where the operation of unnerving is sometimes applied 

 in navicular disease, the position of the nerve and muscle is different. 



BOG SPAVIN. 



Synonym. — Varix. 



Definition. — Bog spavin is a distention of the capsular ligament of 

 the true hock joint. The only bones which enter into the formation of 

 this joint are the tibia and astragalus. The swelling, which is tense, and 

 fluctuating, shows itself primarily in front, because in that part the cap- 

 sule is large and loose (Fig, 86). It is accompanied by heat and pain. 



