18 SOUNDNESS. 



about any part of him, that renders, or is likely 

 in future to render him, less useful than he would 

 be without it. And, of course, «'t horse must be 

 unsound, when he has any disease about him, 

 that renders, or is likely in future to render him, 

 less useful than he would be without it. 



Before I proceed further, perhaps I had better 

 explain what the word disease means ; lest it 

 prove as great a puzzler as unsoundness itself. 

 It may be shortly stated to mean deviation from 

 the healthy structure, or function, or both, of a 

 part or the whole of the frame. Every part of 

 an animal has a texture or structure peculiar to 

 itself in health, and every part has its duty or 

 function to perform ; and every part is subject 

 to alteration in structure, and interruption in 

 function : and thus we have two kinds of disease. 

 An example will illustrate this. It is the duty 

 of the liver to make bile, to answer a certain 

 purpose in the animal economy : but if the bile 

 is made so deficient in quantity or quality as not 

 to serve that purpose, then we say there is a 

 functional disease of the liver. Again, if the 

 liver be altered in bulk, or hardened or softened, 

 or in any other way deviates from its natural 

 and healthy texture, then we say there is organic 



