THE RESPIRATORY SYSTEM 97 



causative organisms may gain entrance to the pleura 

 from the lungs through puncture wounds, through the 

 blood, and through the lymph. 



Lesions. The pleura becomes hyperemic, tumefied, 

 and dry. This stage is succeeded by an outpouring of a 

 serous, fibrinous, or hemorrhagic exudate upon the 

 pleural surface. Should the disease be due to the activity 

 of pyogenic organisms the exudate will soon become 

 purulent, and the future changes depend upon the nature 

 of the exudate. Serous exudate may accumulate in 

 quantities in the pleural cavity, and remain fluid 

 although it may contain flakes of coagula. The 

 fibrinous and hemorrhagic exudates coagulate early and 

 produce greater or less adhesion of the visceral and 

 parietal pleura. The hemorrhagic exudate is characterized 

 by the presence of quantities of hemoglobin, which 

 gives to it a red or blood color. 



Chronic Pleurisy 



Chronic pleurisy is characterized by the formation of 

 varying quantities of fibrous tissue which produce per- 

 manent adhesions of the two layers of the pleura. There 

 may also be considerable quantities of a fluid (serous) 

 exudate in the pleural cavity, and there may be abscess 

 formation, the pus being circumscribed by a definite 

 capsule. 



Symptoms Difficult breathing, each effort being 

 accompanied by a grunt, and sensitiveness of the thorax, 

 characterize pleurisy. In the acute cases there is inap- 

 petence, high temperature, and usually constipation. 

 Chronic cases frequently show little evidence of dis- 

 turbance. 



The acute type has a relatively short course, ter- 

 minating in recovery, or in death within a few days. 

 The chronic form may persist for weeks or even months. 



Treatment. Remove the cause of the trouble and 

 establish sanitary conditions. The treatment of symptoms 

 as they arise will be of some value. If an excessive 



