CAUSES OF UNSOUNDNESS. 107 



at the point of the toe, situated on the inner side 

 of the wall of the hoof. As the tumour increases 

 in size, it causes the hoof wall to bulge at this point. 

 Its growth is slow, so that evidence as to the existence 

 of this disease would necessarily go to show that it 

 had existed for several months at least. 



Contraction. 



A contracted hoof is one that has diminished in 

 its volume at the quarters and heels, and it arises 

 through diminished functional activity, such as 

 that occurring during lameness. It is not a disease, 

 but symptomatic of it. Hence the reason why 

 contraction of the foot — or it may be feet — occurs 

 in such diseases as navicular lameness, side-bone, 

 etc. It is not a difficult matter to tell when 

 one foot is contracted, by comparing it with its 

 fellow ; but if both feet are in a similar condition, 

 the amateur will probably overlook its existence. 

 Not only is contraction symptomatic of disease, 

 but it also predisposes to it, owing to the pres- 

 sure which the contracted wall exerts upon the 

 soft structures contained within the back part of 

 the hoof. 



Navicular Disease. 



This disease is confined to the structures within 

 the hoof ; and the parts participating in the disease 



