PNEUMONIA 593 



Later this is replaced by a harsh, grating sound, and after the lung 

 has become sohd by the throwing out of an exudate into the air 

 spaces a very loud tubular breathing can be heard. This loud 

 tubular sound is very much different from any other sound heard 

 over the lung in disease, and is highly diagnostic to the trained ob- 

 server. Later in the disease, after the crisis has occurred, gurgUng 

 rales can be heard, indicating that the exudate is softening up and 

 being removed. These sounds over the chest are of great import- 

 ance in watching the course of the disease. 



Postmortem Diagnosis. — In hogs that die of pneumonia the 

 postmortem findings are quite characteristic. If we open the body 

 of the dead animal the important changes will be found in the organs 

 of the chest cavity. The affected lung will be found to have lost 

 its normal elastic, sponge-like consistency, and instead will be found 

 to be solid, very much resembling liver. On account of this re- 

 semblance to liver tissue the lungs are said to be hepatized. The 

 color of the affected lung will vary somewhat with the stage of the 

 disease process. If the animal dies soon after the chill the lung 

 will be found to be bright-red in color and enormously congested 

 with blood. Later on in the disease this bright-red color changes 

 to a chocolate brown, and about the time of the crisis it is 

 changed to a yellowish-gray color, due to the invasion of the 

 diseased areas by white blood-cells. The lung is much heavier 

 than normal, and a portion of it is cut off and placed in water will 

 sink to the bottom of the glass. Healthy lung tissue will float in 

 water. 



It is sometimes a question as to whether the disease present is 

 pneumonia or hog-cholera. This is sometimes very hard to decide. 

 As has already been stated, pneumonia is a very frequent complica- 

 tion of hog-cholera, and in many cases the postmortem signs are 

 almost entirely those of pneumonia. The history will be of some 

 importance. If cholera is in the vicinity, suspicion should always • 

 be aroused. In cholera there will usually be some other signs of 

 the disease, either turkey-egg spotting of the kidney, ulcers in the 

 bowel, spots on the skin, hemorrhages into the lymph-glands, or 

 mottling of the surface of the lungs with bright red spots. How- 

 ever, there will be some cases in which the diagnosis will be im- 

 possible without observing the further course of the disease. In 



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