PATHOLOGY OF SPAVIN. 73 



anchylosis. I have likewise seen instances — and in the different 

 veterinary museums exist preparations of the kind — in which 

 the entire articulatory mechanism of the hock has been encrusted 

 and rendered immovable by a complete coating of exostosis. In 

 general, however, the ossification is confined to the two cushion 

 bones, they commonly being the first to contract bony union ; next 

 to them, the articulation between the lower cushion bone and the 

 large metatarsal appears to suffer ; lastly, that between the upper 

 cushion bone and the astragalus. 



Ready-formed Spavin attended with Lameness beine: 

 the case usually presented to our notice, it becomes of importance 

 that we should, as well as we can from observation and experi- 

 ence, make ourselves acquainted with the rationale of a case so 

 common. Supposing it to be a first attack, and a recent one, the 

 owner of the horse representing that he has never been lame of the 

 limb previously, it is of some consequence to know whether there 

 had occurred any precedence in the appearance of the tumour and 

 the lameness, also the period of time which one or both had taken 

 to discover themselves. My own experience inclines me to the 

 belief that in most cases the tumour of spavin is preceded by lame- 

 ness: either the horse has been noticed to limp a little in first 

 stepping out of his stable, or to go stiffly with the limb in action, 

 or else to move in his stall stiffly upon it, or to rest it in preference 

 to the opposite limb. One of two things seems certain in these 

 cases; either that the tumour, if of slow growth, has occasioned 

 the animal little pain or inconvenience while forming, or that the 

 exostosis, keeping pace with the progress of the lameness, has been 

 of rapid growth : of which alternatives I am disposed to adopt the 

 latter, and for reasons that will best appear in the annexed case, 

 one selected from others whereon observations made had proved 

 similar : — 



In July 1841, Captain B requested me to look at his 



second charger, the animal having gone, as he said, " very lame 

 behind, the day before, while being ridden out." I examined the 

 horse, but could detect no lameness whatever, although the trial trot, 

 and sudden pull up, and turn-about, were several times repeated ; 

 neither did there appear any thing about the limbs to argue the 



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