150 VETERINAEY STATE BOARD 



tone, yields more readily to the internal tension and as a result an 

 enormous distention and thickening of the wall occurs. 



Respieatoby Organs 



What pathologic changes occur in the air-cells during pulmonary 

 hepatization? 



Hyperaemia, smaller or larger hemorrhagic foci, extravasation 

 of blood-serum with white and red blood-corpuscles into the alveoli. 



Describe the post-mortem appearance of each stage of pneumonia. 



First stage (congestive) : Capillaries distended and the alveoli 

 fiUed with serous fluid containing endothelial and red blood-cells. 



Second stage (red hepatization) : Fibrinous exudate and red 

 blood-cells in the air sacs, coagulation of same ; lung is consolidated, 

 dark-red and friable, does not collapse when thorax is opened and 

 shows the imprint of the ribs; sinks in water; the cut surface 

 appears granular from the projection of fibrin plugs. 



Third stage (gray hepatization) : The red cells are gradually 

 destroyed and absorbed, and leucocytes predominate, giving the 

 cut surface a gray appearance. 



Fourth stage (resolution) : The exudate has undergone fatty 

 degeneration and liquefaction; the cut surface is smooth and 

 exudes a whitish fluid; the lung is approaching normal color and 

 condition. 



Give the post-mortem appearance of gangrene of the lungs. 



In the anterior and inferior portions of the lungs, gangrenous 

 foci are found, which appear dirty-brown, red or yellowish-brown, 

 and consist of a soft mass of a very disagreeable, sweetish, foul odor. 

 The bronchi contain liquefied or soft masses of a similar color and 

 smell. The mucosa of the bronchi is slate-gray in color. The 

 internal surface of the cavities formed is ragged and covered with 

 a friable, stinking, mushy mass. If the cavity is near the pleura 

 or breaks through the same, purulent pleurisy may be present. 

 Between the foci the pulmonary tissue shows a catarrhal or fibrinous 

 pneumonia. 



Describe the post-mortem lesions of pulmonary emphysema (heaves). 



The lungs are enlarged, soft, less elastic and paler in color. 

 Their surface often shows the imprint of the ribs. Air vesicles can 

 be seen with the naked eye. Between the vesicles are large air 

 spaces due to rupture of the walls. These air spaces often produce 

 bulging of the serous coat in various places when beneath the 

 pleura. 



