4ii 



Journal of Agriculture. 



[8 July, 190; 



while the lammse are specially involved, the inflammation in most cases 

 affects all the sensiti^■e blood-vascular structures of the foot and the term 

 " peditis " (foot inflammation) would more aptly describe the condition. 

 The disease affects all classes of horses and although all shapes of hoof 

 are liable, the predisposition to attack is strongest in the case of horses 

 having wide flat feet with weak heels and flat soles. The two fore feet 

 onlv are mostly affected. Sometimes all four feet are involved, but of the 

 hind feet it is seldom that more than one is affected at a time. 



Laminitis is one of the most painful affections that can be imagined 

 because the inflamed structures are confined within a hard unyielding 

 case of horn and there is consequently no room for the expansion of the 

 swelling which accompanies the inflammation. The pressure upon the 

 sensory nerves of the foot is therefore such as to give rise to excruciating 

 pain, by which the grave constitutional svmptoms which often accompany 

 an attack are caused. Even in the early stages, or in mild cases when 

 there is no actual inflammation but when the blood vessels are merely 

 over-full or congested, the pain is very great and accounts for the peculiar 



Fig. 57. Section through foot of horse — normal. (After Ha\es.) 



method of progression on the heels which will be described, and also for 

 the great disinclination of the animal to move. 



Causes. — The most common cause is concussion, especiallv when the 

 circulation is weakened by over driving. Horses most frequentlv become 

 foundered by being driven long journeys on hard roads when out of 

 condition. When in this state the heart's action is weak and the circula- 

 tion sluggish so that congestion of the blood vessels of the foot is easily 

 brought about and inflammation supervenes. 



Laminitis is also frequently associated with or occurs as a sequel to 

 inflammation of the bowels, lungs and womb ; and verv often superpurga- 

 tion, caused by an overdose of physic or the giving of purgatives when the 

 bowels are in an irritable and colicky condition, is followed bv an attack. 

 In these cases the inflammation is said to " fly to the feet." The phe- 

 nomenon of this change of situation is called " metastasis." What defi- 

 nitely determines the change is only vaguely understood but in this con- 

 nexion it requires to be borne in mind that the mucous lining of the 

 bowels, lungs and womb is continuous, through the skin, with the sensitive 

 laminae of the foot. A congestion in one part of a continuous membrane 

 is apt to be transmitted to another part some distance away, as is well 

 seen in irritation of the skin following indigestion in man. This crude 

 statement of a generally accepted view regarding metastasis is supported 

 by the fact that in laminitis so brought about it is onlv the sensitive 

 laminae that are involved and not the whole of the vascular structures of 



