CAUSES OF DISEASE. 35 



with it. We say apparently advisedly, because, although 

 the acute inflammation subsides, it too often gives 

 place to a chronic inflammation that extends over 

 years. This chronic inflammatory state is no longer 

 dependent in most cases upon the infectious principle 

 which caused the initial lesion, but is a slow sclerosis, 

 or cicatrization, which consists in a gradual contraction 

 and substitution of the normal tissues of a part by scar 

 tissue. The change is especially prone to occur in 

 organs that have sustained an injury of one kind or 

 another, and is really a vicarious evolution that the 

 tissues are subject to. There is a danger in the new 

 condition that arises both from the contractions, and 

 the loss in organic cellular constituents, since in the 

 one case functions are interfered with, in the other, 

 metabolism* is disturbed. The seriousness of the 

 lesion depends upon the organ in which the original 

 injury was located, and its importance to the vital 

 processes of the body. One or two illustrations will 

 suffice to elucidate our point. A person has typhoid 

 fever and apparently makes a complete recovery. Ten, 

 fifteen or twenty years afterwards he seeks medical 

 advice for shortness of breath and cough. His case 

 is diagnosed as chronic heart disease. Whence came 

 the lesion of his heart valves ? When closely questioned, 

 he may remember that the physician who attended 



* Metabolism— chemical change within the body m nutrition and 

 secretion. 



