INFLAMMATION. 281 



DISEASES OF THE RESPIRATORY ORGANS 



INFLAMMATION. 



The diseases of the respiratory organs and air passages are 

 generally of an inflammatory type. In order to fully under- 

 stand the various diseases to which these important organs are 

 subject, a few remarks regarding the nature of inflammation, its 

 progress, &c., may not be out of place in a work like the 

 present. 



Inflammation, then, is a state of altered nutrition, an increased 

 vascularity and sensibility of the parts involved, together with 

 a tendency to change of structure. The symptoms are swelling, 

 pain, heat, and redness where the parts are not covered with 

 hair. The redness is in consequence of a redundancy of blood 

 in the inflamed part, which distends the small capillaries with 

 red particles of blood. When the inflammation is acute, the 

 parts present a bright red or crimson hue ; when it is chronic, 

 they are of a dark or purplish red color. As the various terras 

 employed by authors to indicate the various degrees are unin- 

 teresting to the general reader, no attempt at detail is here 

 made. 



The sensation of pain is mainly due to a stretching of the 

 nerves by the distended blood-vessels. It difi'ers in its char- 

 acter and intensity according to the parts involved, varying 

 from a burning, throbbing, sharp, and lacerating pain to a 

 mere sense of heat, soreness, and a dull sensation of pain. The 

 heat in inflammation is supposed to arise from an increased 

 quantity of blood in \he inflamed part. The swelling in the 

 early stage is dae lo the iJicreascd quantity of blood, and 



