SECTION IV 



DISEASES OF THE PLEURAE 



Pleurisy 



(Inflammation of the Pleura; Pleuritis) 



The disease is found in two forms, primary and 

 secondary pleuritis. The primary form is usually 

 caused by exposure to cold, especially when the 

 coat is wet, as in sporting dogs after swimming, or 

 running through wet underbrush. Secondary 

 pleurisy appears as a complication of other dis- 

 eases, such as pneumonia, pericarditis, peritonitis 

 (extending from the abdominal cavity through the 

 diaphragm), fractured ribs, punctured wounds of 

 the thorax, perforation of the esophagus by for- 

 eign bodies, tuberculosis, or pyemia. 



Morbid Anatomy. — The pleura is dull and tume- 

 fied and very hyperemic. Its surface is roughened 

 by accumulations of fibrin and in appearance may 

 be likened to the surfaces of two pieces of bread 

 and butter- that have been placed together and 

 then separated. When there is no accumulation of 

 fluid it is termed dry pleurisy, or pleuritis fibrinosa. 



Usually, however, exudation takes place and an 

 accumulation of a serous fluid in which fibrinous 

 coagula float, is found between the pleural folds. 

 This pleuritic fluid, closely resembling blood serum, 

 contains cells, and, according to the number of red 

 blood corpuscles it contains, is of a straw color or 

 of a sanguineous color. 



In secondary pleuritis, infection with pyogenic 

 organisms may take place and then the fluid be- 



31 



