OF DISEASE GENERALLY. 



Disease is a morbid affection of a part or of the whole of 

 the body, whereby the exercise of some of its functions is 

 altered or suspended. The causes of disease are various ; 

 some of them are evident, others are obscure. We call the 

 cause remote when it can only be guessed at or surmised. 

 It is termed predisposing when inherited, or the conse- 

 quence of a particular formation ; thus small carcassed horses 

 are prone to constitutional diarrhcea, and those with oddly 

 formed hind legs are said to be predisposed to curb. There 

 are also proximate or exciting causes constantly acting in 

 the production of disease ; thus a horse, violently heated 

 during hunting, plunges into a river, and inflammation of 

 the lungs follows. Here the violent action of the lungs 

 had predisposed them to become diseased ; but the cold 

 bath was the exciting cause of the disorder. A nipping 

 wind, with sleet, blows on cattle purposely fed high for 

 sale ; they take a cold, for they had been hitherto not ex- 

 posed to so frigid a temperature. Here the excessive feed- 

 ing predisposes, and the cold excites the malady. 



Diseases for many centuries were principally attributed to 

 an affection of the fluids or humours of the body, and this 

 theory was termed the humoral pathology. The blood then 

 was the favourite agent which diseased the entire body ; but 

 by advanced knowledge we now comprehend that the blood, 

 though apparently a fluid, contains no inconsiderable portion 

 of solid particles, and also that gas, fluid, and solid are but 

 names for diflerent states which any form of matter may 

 under favourable circumstances assume. There are now 

 living physiologists who reject entirely the fluids, and attri- 

 bute every thing to the solids, and these, for the reasons 

 stated above, are as far wrong as their predecessors. The 

 bone, which is the most solid substance in the body, is 

 deposited and absorbed in a fluid state ; which instance may 

 serve to show how both systems are united by nature, since 



