DIAGNOSIS, DIFFEBENTIAL DIAGNOSIS, PEOGNOSIS 65 



care being taken to make the examination in a 

 strong light. Infrequently other causes produce 

 peteehias in the kidneys of swine, but in this coun- 

 try, unless another cause is apparent, either by 

 virtue of the history or accessory lesions, we are 

 safe in attributing them to hog cholera. 



Petechiae in the mucosa of the bladder occur in 

 most cases of hog cholera, and they do not often 

 result from other causes. The serous surface is 

 practically always normal. 



Some of the lymph glands are usually involved, 

 and to the experienced observer the changes in 

 them aid greatly in making a diagnosis. On the 

 surface the gland is very dark red, almost black. 

 On section the periphery is similar in color, while 

 the deeper structures may remain unchanged. It 

 is important to bear in mind that any inflamma- 

 tory process may affect adjacent lymph nodes, and 

 to make allowance for this fact, but marked per- 

 ipheral congestion or hemorrhage, when observed 

 in several glands widely separated, in the absence 

 of apparent inflammation in adjacent structures, 

 strongly indicates hog cholera. 



The spleen reveals characteristic hog cholera le- 

 sions only in the dark, swollen circumscribed hem- 

 orrhages, usually less than 1 centimeter in diam- 

 eter, which appear along the border. In field 

 cases that have died of hog cholera these lesions 

 are not often observed, because secondary invad- 



