52 MORBID ANATOMY 
reddened. The skin over the ventral surface of the body, nose and 
ears is frequently flushed. The cough, however, is the most reliable 
indication we have of swine plague; but in some cases of hog cholera 
the coexistence of broncho-pneumonia also causes the animal te 
cough when forced to move rapidly. 
Morbid anatomy. There are many known variations in the 
appearance of the internal organs of hogs which have died of swine 
plague. The most characteristic lesions are to be found in the lungs. 
Frequently the abdominal viscera appear to be normal, although a 
careful examination will usually reveal slight changes. In the lungs, 
however, the disease is ordinarily obvious. 
The variety of lesions produced by the inoculation of swine plague 
bacteria is not so great as that observed in the naturally contracted 
disease. While there are outbreaks in which considerable uniformity 
is observed, there are others in which each animal is a surprise to the 
pathologist. In general it may be stated that the lungs and the diges- 
tive tract are the chief seats of the disease, though other organs, 
notably the lymphatic glands, are secondarily involved. The lesions 
are localized in the lungs and in the digestive tract probably because 
the bacteria gain entrance through the respiratory and digestive 
passages. 
The lungs have been found diseased in nearly every outbreak 
which has been investigated. In some outbreaks the lung lesions 
predominated and pneumonia was the direct cause of death. In 
individual cases, pneumonia is absent but pleuritis and interlobular 
edema are generally present. In a few instances interlobular emphy- 
sema of the lungs has been observed. With pneumonia the seat of 
the lesion varies: usually the ventral lobes are first attacked, then 
the cephalic and azygos, and lastly the principal lobes. This move- 
ment of the disease seems to depend on gravity, inasmuch as the dis- 
eased parts are marked off from the healthy portion by a nearly 
horizontal line. In other words, the most dependent portions of the 
lungs are the ones affected first, and as the disease progresses upwards 
only a small port’on of the principal lobe directly under the back of 
the animal remains pervious, provided the life of the animal is main- 
tained up to this point. In cases where disease is caused by lung 
worms or by embolism, the pneumonia involves portions of the 
principal lobes not contiguous to the ventral lobes. 
