60 SWINE DISEASES 



If the obstruction has existed for some time, icterus will 

 usually be more or less pronounced. 



Upon opening the gall bladder or bile ducts containing 

 the calculi, thick grumose bile escapes and the con- 

 crements or calculi are observed. Gall-stones may 

 occur singly, but they are usually multiple. They are 

 usually of a brownish-chocolate color and vary in size 

 from mere specks to masses an inch or more in diameter. 

 They may be round or any other shape, and when many 

 are present they are usually faceted where they come 

 into contact with each other. The gall-stones may be 

 composed of organic material entirely and be quite soft 

 or they may be incrusted with mineral matter and be 

 quite hard. Upon sectioning them they are usually 

 found to have been made up in layers, and it is not 

 difficult to distinguish the nucleus. There is an inflam- 

 mation of the mucous membrane of the gall bladder or 

 affected bile tubes. 



Symptoms. Very few if any cases of cholelithiasis 

 have been recognized clinically. If the gall-stones 

 obstruct the outflow of bile sufficiently there will be 

 general icterus. There are probably some digestive 

 disturbances also. 



Treatment. The nature of this condition does not 

 warrant treatment. 



Hyperemia 



Hyperemia of the liver may be physiologic or patho- 

 logic. Physiologic hepatic hyperemia occurs after eating 

 and is of no significance economically or pathologically. 

 Pathologic hepatic hyperemia may be either venous 

 (passive) or arterial (active). 



Passive hepatic hyperemia is caused by obstructed 

 outflow of blood. Cardiac defects of the valves of the 

 right side of the heart are a potent cause. Obstruction 

 of the posterior vena cava or the hepatic vein by new 

 growths, abscesses, and cicatricial tissue will also produce 

 venous engorgement of the liver. 



