KNBE, FETLOCK, ANKLE, AND FOOT. 205 



Founder or I/aminitis. This in its simple form is infiammatiou 

 of the sensitive laminae which cover the outer and upper surface of the 

 coffin bone. The laminae consist of five or six hundred very fine folds, 

 which are profusely supplied with blood-vessels and nerves. 



This inflammation is of a character similar to that which attends in- 

 flammation of the skin and mucous membranes, producing no constitu- 

 tional disturbances except those dependent upon the local disease. In 

 severe cases it has a strong tendency to destroy destructive disorganization 

 of the tissues affected. 



Causes. These are wide and variable and may be divided into pre- 

 disposing and EXCITING. 



PREDISPOSING CAUSES. A predisposing cause exists to an ex- 

 tent in those animals unaccustomed to work, particularly if they are in- 

 active, and in all those that have had previous attacks of the disease, for 

 the same rule holds good here that we find in so many diseases: i. e., 

 that one attack impairs the activity of the affected tissues and thus 

 renders them more subject to a subsequent inflammation. 



Unusual excitement by causing an excessive blood supply, bad shoe- 

 ing, careless paring of the feet by removing the sole support, as well as 

 high-heel calkings without corresponding toe pieces, must be included 

 under this head. 



EXCITING CAUSES. These are many and varied, the most com- 

 mon are rapid changes of temperature, over exertion, exhaustion, in- 

 gestion of various foods, purgatives, and metastasis. 



I . Rapid change op temperature. This acts as an excitng cause of 

 laminitis in precisely the same way as they act to produce disease in other 

 tissues, the result of these variations of temperature showing itself upon 

 those parts which are particularly liable to the changes from some loss 

 of their natural disease-resisting powers. 



This change of temperature may be induced by drinking large quan- 

 tities of cold water while in an overheated condition. Here the internal 

 heat is rapidly reduced, the neighboring tissues and blood-vessels con- 

 strained, and the blood supply to these organs greatly diminished, while 

 the quantity sent to the surface is correspondingly increased. In many 

 of the cases which result from this cause there has not been sufficient labor 

 performed to impair the powers of the laminae, yet it seems that laminitis is 

 more readily induced than congestion or inflammation of the skin or other 

 surface organs because of the impossibility upon the part of the laminae 

 to relieve themselves of the threatened congestion by the general safety- 



