MORBID ANATOMY I 75 



examination and even then the diagnosis must often be delayed 

 until the results of a bacteriological examination have been 

 obtained. It not infrequently happens that swine suffering 

 from hog cholera are attacked with swine plague, the two 

 diseases co-existing in the same animal. 



§ 137. Morbid anatomy, {a) The acute type. This 

 might with equal propriety be called the hemorrhagic or sep- 

 ticaemia type, inasmuch as the chief and perhaps the only 

 obvious changes are hemorrhagic in nature. They are more 

 conspicuous when an animal is examined immediately after 

 death. The spleen is variably enlarged, soft, and gorged with 

 blood. Sometimes it is twice as long as the normal spleen 

 and the other dimensions being proportionately increased it 

 may extend across the median line to the right side. Next to 

 the spleen, the lymphatic glands and serous membranes are 

 most severeh' involved. The cortex of the glands appears on 

 section as a hemorrhagic line or band, according to the amount 

 of extravasated blood, or the entire gland may be infiltrated 

 with it. Among the glands most connuonly hemorrhagic are 

 those of the meso-colon, those at the root of the lungs, and on 

 the posterior thoracic aorta. Besides these, the retro-perito- 

 neal and the gastric glands may be involved. More rarely the 

 mesenteric glands show slight blood extravasations. Hemor- 

 rhages are also quite frequent beneath the serous surfaces of 

 the abdomen and thorax. They are most abundant as pete- 

 chiae and larger patches under the mucous memljrane of the 

 large and small intestines. Thej' are occasionally found under 

 the peritoneum near the kidneys, the diaphragm and the costal 

 pleura as extravasations nearl}' an inch in diameter. 



The lungs, in a small percentage of cases, show subpleural 

 ecchymoses in large numbers and on section small hemor- 

 rhagic foci are observed throughout the lung tissue. In a few 

 cases severe hemorrhages involving one or more lobes have 

 been observed. The kidneys are occasionly the seat of extensive 

 hemorrhagic changes. The glomeruli appear as blood red 

 points ; larger extravasations occur in the medullary substance 

 and blood ma^' collect around the apices of the papillae. The sub- 

 cutaneous tissue over the ventral surface of the body may be 



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