44 HOG CHOLERA 



but necrotic patches due to secondary infection 

 with Bact. necrophorus may appear. Serosa usu- 

 ally normal. Exceptionally studded with puncti- 

 form hemorrhages, due to filterable virus. 



Small intestine. Mucosa sometimes normal. 

 Congestion rather common, also hemorrhages sim- 

 ilar to those observed in stomach, and due to filter- 

 able virus. Lymphoid nodules often congested, 

 less frequently hemorrhagic, due to filterable vir- 

 us. Those in ilium most frequently involved. 

 Ulceration rather uncommon, except in extreme 

 posterior portion of ileum. Serosa usually nor- 

 mal. Petechial hemorrhages appear infrequently, 

 mesentery often congested. Changes due to filter- 

 able virus. 



Caecum and upper colon. Mucosa most con- 

 stant seat of digestive canal lesions, especially 

 region of iliocecal valve. Congestion, petechise, 

 ecchymoses 1 and larger suffusions common. 

 Strong tendency toward ulceration. Pitlike 

 patches denuded of epithelium. Necrotic ulcers 

 or patches, dark brown in color, sometimes false 

 membrane ; ulcers tending to broaden and deepen, 

 little tendency toward regeneration. " Button 

 ulcers ' ' 1 occur in chronic hog cholera. Serosa 



1 The ulcers may be isolated and appear as circular, slightly 

 projecting masses stained yellowish or blackish or both in alter- 

 nate rings, or they may be slightly depressed and somewhat ragged 

 in outline. When the superficial slough is scraped away many 

 ulcers show a grayish or white base. A vertical section reveals a 

 rather firm neoplastic growth, extending usually to the inner mus- 



