INTRODUCTION. 



bruised heel, he will be as sure to go lame as he would with 

 an ordinary sprain. The difference is, that he not only 

 stretches out the sore foot, but he elevates the heel from 

 the ground, and will not set his foot flat to please, or it 

 may be said to deceive any one. The uneasy eye, the 

 anxious expression, and the sharp, peculiar look, tell its 

 tale of suffering, and bear testimony to a description so 

 faithful and true, that every man should understand how 

 to interpret them. 



The Principles of Disease. 



Congestion. — By this term is meant an undue flow of 

 blood into a part, and remaining in it. The blood-vessels 

 lose the power of contracting and emptying themselves, 

 as when in health. Congestion is not accompanied with 

 inflammation, as some suppose, and may exist without 

 irritation. Irritation is only present when the blood 

 passes more rapidly into a part than its vessels can carry 

 it out, and inflammation only is present when more fluid 

 is thrown into the vessels than they can get rid of. 



Irritation. — This peculiar condition is the result of in- 

 creased sensitiveness, or an exalted action, accompanied 

 with quickened beating of the heart and pulse. When 

 we apply the term to special cases, it will be better un- 

 derstood, as irritation of the howels producing diarrhoea, of 

 the bladder frequent passing of urine, of the eye causing 

 an increased flow of tears, and of the throat giving rise 

 to cough. 



Inflammation differs from irritation, inasmuch as it is 

 more painful. There are three varieties — acute, sub-acute, 

 and chronic. Inflammation has also three terminations : — 



