48 ULCERATIVE DISEASE OF JOINTS. 



Supposing the lame horse to be laid up on the discovery of 

 his lameness, it very often happens that after two or three da3^s 

 repose he comes out of his stable going much less lame, all but 

 sound perhaps : the inflammation that supervened on the injury 

 to the synovial membrane, generally of the sub-acute character, 

 has in this instance proved a mild attack, and in reality has 

 tended rather to the animal's benefit than otherwise ; has probably 

 nearly or quite healed up the breach made in the membrane, and 

 so enabled the horse to go comparatively painlessly. A very little, 

 however, must be expected to open the breach again, filled up as it 

 is only by l}- mphy effusion ; and so in practice we find it, for let the 

 horse be taken out again only but to exercise, and his lameness 

 will surely return. 



When the lameness comes on gradually, and insidiously rather, 

 as sometimes it does, appearing at first so slight as to incline us 

 (from an unwillingness, perhaps, to see any failing in a favourite) 

 to doubt of its existence, we apprehend that the injury to the joint 

 has been such as to excite inflam. nation of a mild character in it, 

 without at once being productive of ulceration in the membrane. 

 Of course, a repetition of injury will excite more inflammation, 

 and that will produce more lameness, and there will speedily be 

 ulceration following : the case, in fact, although its origin has been 

 different, will be reduced to a parallel, in point of pathological 

 nature, with that whose beginning was sudden. 



The effects of this (sub-acute) inflammation on the synovial 

 membrane are these ; — either aggravation of the breach originally 

 made in the form of ulceration, or the production of ulceration 

 where no breach has existed. But this ulceration does not appear 

 to be productive of any (or of but extremely little) purulent secre- 

 tion; else we should at times see abscess of the joint during life, or 

 collections of purulent matter after death, which we know never to 

 be the case. There appears a decrease in the supply of synovia, 

 while in the ulcerations there is an evident tendency to throw out 

 lymph, as if to granulate. After the inflammation a softening 

 takes place of the articular cartilages, deep into which the ulcer- 

 ation has sunk, and which, in point of fact, has been its bed or 

 bottom from the commencement. Ulceration and softening of the 



