DISEASES OF THE FETLOCK. ANKLE. AND FOOT. 141 



Since linglxnie is loiisideii'tl to U' t)iu' »»f the luTt'tliiaiv disease.^, no 

 animal ^sutfe^ing from this troiilile slioiiM ever l»e used for breeding 

 purposes. 



LAMIMTIS, OK 1 Ol NDER. 



Laminitis is a simple intlammation of tlio sensitive laminie of the 

 feet, characterized hy the general i)lienomena attending inflauima- 

 lion of the skin and mucous njembianes, prochicing no constitutional 

 disturbances except those dependent upon the local disease, and hav- 

 ing a strong tendency, in severe cases, to destructive disorganization 

 of the tissues affected. 



('im.s(s. — The causes of laminitis are as Avide and variable as in any 

 of the local intlannuations, and may ]>e divided into two classes — the 

 j)redisposing and the exciting. 



Pn (h',s/)Of<i/i(/ c(iii,se>i. — From personal observation I do not know 

 that any particular construction of foot or any special breed of horses 

 is predispo>ed to this disease, neither can I find anything to warrant 

 the assumption that it is in any way hereditary; so that while we 

 may easily cultivate a predisposition to the disea.se, it does not origi- 

 nate without an exciting cause. Like most other tissues, a predispo- 

 sition to inflannnation may be induced in the sensitive laminie by any 

 cause which lessens their power of withstanding the work imposed 

 on theuL It exists to an extent in those animals unaccustomed to 

 work, particularly if they are plethoric, and in all that have been 

 previous subjects of the disease, for the same rule holds good here 

 that we find in so many disea.ses — i. e., that one attack impairs the 

 functional activity of the affected tissues and renders them more easy 

 of a subse(iuent inflannnation. Unusual excitement by determining 

 an excessive blood supply, bad shoeing, careless paring of the feet by 

 removing the sole suj^port. and high calkings without coi'responding 

 toe pieces must be included under this head. 



Ercitimj <aiiH€H. — The exciting cau.ses of laminitis are many and 

 varied. The most comm<^)n are concussion, overexertion, exhaustion, 

 rapid changes (»f temj)erature. ingestion of certain feeds, purgatives, 

 an<l the oft-mentioned metastasis. 



(1) Concu.ssion i>roduces this disea.se by local ovei-stimulation. 

 The excessive excitement is followed by an almost complete exhaus- 

 tion of the functional activity «)f the laminated tissues, the exhaustion 

 by congestion, and eventually by infhunmation. But congestion here, 

 as in all other tissues, is not necessarily followed by inllanunation ; 

 for, althoiigh the principal symptoms belonging t<> true laminitis are 

 present, the congestion may bo i-e1ieve<l In'fore the jirocesses of inflam- 

 mation are fully establishe<l. This is the condition in the many so- 

 called cases of laminitis which recover in from 24 to 4S hours. They 

 should be called congestion of the laminir. 



